Merge pull request 'Keep what discovery heard when a round hears nothing, and fetch only changed announcements (issue 554)' (#32) from fix/554-empty-discovery-round into main

A round in which no PING reached the laptop's console within the 750 ms window
was taken as the mesh's answer that nothing is there, and replaced the index:
every seat and module call was refused for five seconds at a time. Discovery
now waits up to its patience for a first PING, a round that heard nothing is
not kept, a runtime not heard this round is resolved from what it announced
last (said with its age), and a round that misses runtimes is logged once.
A PING carries a digest of what the instance serves, so an unchanged
announcement is not pulled again every round (some 880 kB to the laptop).

.gitignore

@@ -1,2 +1,3 @@
 node_modules/
 dist/
+.mesh-build/

Dockerfile

@@ -1,5 +1,8 @@
 ARG NODE_BASE=node:22-bookworm-slim
-# Three stages, two published images: the one modules are COMPILED in, and the one they RUN in.
+# The mesh-tools module: the two images every TypeScript module is COMPILED in and may RUN in. The
+# runtime itself ships as the node-tools module's bundle (node-tools/, novox/hq ADR 0175, to-be 38
+# WP3); these images are the toolchain for TypeScript bundles and the base a module's own service
+# may still be built on. They are no longer how tools reach a node.
 #
 # **They were the same image, and that was a mistake.** A module's recipe starts from this and
 # invokes the compiler out of it, so the compiler had to be here — and because the same image was
@@ -19,36 +22,64 @@ RUN apt-get update \
       && apt-get install -y --no-install-recommends git ca-certificates \
       && rm -rf /var/lib/apt/lists/*
 WORKDIR /app
-COPY package.json ./
+COPY node-tools/package.json ./
 # The builder writes .npmrc into the build context; it authenticates to the mesh's package registry
 # for the @novox scope, which is where @novox/mesh-sdk resolves. This stage is not published, so the
 # credential travels no further than here. Development dependencies included: the compiler is one.
 COPY .npmrc ./.npmrc
 RUN npm install --no-audit --no-fund
+# **The SDK this image carries is the one the mesh last published** (novox/hq issue 212). The range in
+# package.json is resolved once and the layer above is cached, so a release reached no toolchain until
+# that file changed. The exact version arrives as a build argument from the SDK module's published
+# package (module.json `build.on`), so a new release is a new argument, this layer runs again — and
+# the planner orders this module after the SDK, so a release rebuilds the toolchain and, after it,
+# every bundle compiled in it (issue 211).
+ARG MESH_SDK=@novox/mesh-sdk@latest
+RUN npm install --no-audit --no-fund "${MESH_SDK}"
 
-# ---- toolchain: what a module is compiled in, WITHOUT the credential --------------------------
+# ---- compiling: the runtime's own code built, WITHOUT the credential -------------------------
-FROM ${NODE_BASE} AS toolchain
+FROM ${NODE_BASE} AS compiling
 WORKDIR /app
-COPY package.json ./
+COPY node-tools/package.json ./
 # The resolved libraries, but not the .npmrc that resolved them.
 COPY --from=deps /app/node_modules ./node_modules
-# The toolkit arrives compiled. It used to arrive as sources, and this compiled it by hand — the
+COPY node-tools/tsconfig.json ./
-# hook that builds it on install was running all along, and the result was then packed out of the
+COPY node-tools/src ./src
-# package, because with no explicit file list npm falls back to .gitignore and that ignores the
-# build output. Fixed where it belonged, in the toolkit.
-COPY tsconfig.json ./
-COPY src ./src
 RUN npm run build
 
-# ---- what the running image needs, and nothing else -------------------------------------------
+# ---- what a running bundle needs, and nothing else -------------------------------------------
 # Its own stage so the toolchain image keeps its build tools while the runtime image does not.
-FROM toolchain AS lean
+FROM compiling AS lean
 RUN npm prune --omit=dev
 
-# ---- runtime: what a module runs in -----------------------------------------------------------
+# ---- toolchain: what a TypeScript bundle is compiled in ---------------------------------------
+# The compiler, and esbuild (a development dependency) at /app/node_modules/esbuild: the builder
+# bundles every entrypoint and launcher into one file with it (novox/hq ADR 0193), so a bundle
+# carries what it imports and not this image's node_modules.
+# Beside the compiler, at /app/runtime, what every TypeScript bundle runs with: the production
+# dependencies the SDK and the runtime need, and a package.json saying the compiled files are ES
+# modules. The builder copies this directory whole into a compiled bundle (novox/hq ADR 0188 §5),
+# so a bundle unpacked on a machine starts — a `.js` without that package.json is read as
+# CommonJS, and an import of `nats` without node_modules beside it resolves to nothing.
+#
+# **The client libraries a catalogue module depends on are here too** (novox/hq issue 385): pg, mongodb and
+# mssql, development dependencies of node-tools, so the runtime stage prunes them. A catalogue's
+# merge-check-typescript.sh fetches nothing and copies this image's node_modules beside a module; a module
+# depending on a package that is not here cannot be type-checked or tested, and fails its check.
+FROM compiling AS toolchain
+COPY --from=lean /app/node_modules /app/runtime/node_modules
+RUN printf '{"type":"module","private":true}\n' > /app/runtime/package.json
+# **git, because a pull request's merge check runs in this image too** (novox/hq ADR 0237): a repository's
+# own merge-check.sh that declares this toolchain runs here, and a suite that reads a repository's history
+# (the lab's last-run record) ran into "spawnSync git ENOENT". Nothing compiled here calls it.
+RUN apt-get update \
+      && apt-get install -y --no-install-recommends git \
+      && rm -rf /var/lib/apt/lists/*
+
+# ---- runtime: what a module's own service may run in ------------------------------------------
 FROM ${NODE_BASE} AS runtime
 WORKDIR /app
-COPY package.json ./
+COPY node-tools/package.json ./
 COPY --from=lean /app/node_modules ./node_modules
-COPY --from=toolchain /app/dist ./dist
+COPY --from=compiling /app/dist ./dist
 ENTRYPOINT ["node", "dist/main.js"]

README.md

@@ -1,32 +1,95 @@
 # mesh-tools
 
-The Novox Mesh **tool runtime** — the per-node process that makes a module's tools actually serve.
+Two modules in one repository (novox/hq ADR 0069), one piece of software:
 
-A module ships its tools (built on [`@novox/mesh-sdk`](https://git.novox.be/novox/mesh-sdk)); this
+- **`node-tools`** (`node-tools/`) — the node's **tool runtime** as a module (ADR 0175, to-be 38
-runtime is what loads them and puts them on the mesh. It:
+  WP3): one process per machine the host runs from this bundle, serving every assigned module's tools
+  and every held seat's verbs on the bus, and answering MCP on the machine's loopback — the console
+  (design 34). The code, its tests and the `mesh` client all live there.
+- **`mesh-tools`** (this directory) — the two images TypeScript bundles are compiled in and a module's
+  own *service* may still run in. Built from the same code; no longer how tools reach a node.
 
-1. connects the mesh broker (novox/hq ADR 0001) — a concrete AMQP implementation of the sdk's
+The runtime:
-   `Broker` contract;
+
-2. imports the assigned modules' compiled tool entrypoints, each of which registers its tools as it
+1. connects the mesh bus on the node's credential — a concrete implementation of the sdk's `Broker`
-   loads;
+   contract;
-3. serves them through the sdk's `serveTools` harness, answering `tools.invoke` over the broker.
+2. reads one membership per module it serves — what the mesh issued that module on this machine
+   (ADR 0160): where its tools are answered, which seats it holds — and follows each live;
+3. imports each module's compiled tool entrypoints, each of which registers its tools as it loads,
+   guarded: a bundle that throws is named, in the log and in what `tools` answers for its module,
+   and the others serve;
+4. serves every module's tools on that module's subjects and every held seat's verbs on the seat's.
+
+A bundle that is not plain JavaScript — a Go or Rust binary, a Python script, or a JavaScript file
+marked executable — is **launched** rather than imported (novox/hq ADR 0188): the runtime starts it
+as a child with its own environment and speaks MCP over stdio to it, `tools/list` once and
+`tools/call` per call. A tool it lists as `<seat>.<verb>` is the seat's implementation. A child that
+exits is named in the log and started again on its next call. So a tools bundle may be written in
+any language; the mesh's SDK for each is the stdio loop and nothing more (`node-tools/src/launch.ts`
+is the runtime's side of it).
 
 Everything hard — dispatch, collection, duplicate-name safety — is the sdk's. This is the thin
-wrapper that binds the broker and loads the modules. Keeping the AMQP client here, out of the sdk,
+wrapper that binds the bus and loads the modules. Keeping the bus client here, out of the sdk, is
-is deliberate: a broker-client change never rebuilds a module (ADR 0039).
+deliberate: a bus-client change never rebuilds a module (ADR 0039). The runtime is module-agnostic:
+it knows bundles and subjects, nothing of what any module does. A tool that needs root escalates
+itself — root is the module's concern, not the runtime's.
 
 ## Running it
 
 ```
-MESH_BROKER_URL     amqp://…              the mesh broker
+MESH_BROKER_FILE        the node's sealed credential, as the mesh delivered it
-MESH_TOOL_MODULES   /a/tools/index.js,…   the assigned modules' compiled tool entrypoints
+MESH_TOOL_MODULES       alpha=/…/alpha/tools/index.js,beta=/…/beta/dist/index.js,…
+                        the modules to serve and their compiled entrypoints; several entries may
+                        name one module. A bare path is an entrypoint of the credential's own module
+                        — the one-module form a per-module container still sets.
+MESH_OPERATOR_ACCOUNT   whose machine this is, and MESH_OPERATOR_HOME where their home is; set by
+                        the mesh when the node has an account, read by tools from their environment
+MESH_BROKER_URL         a plain URL instead of the credential, for the bootstrap case
 ```
 
-`node dist/main.js`, or the container (`Dockerfile`). On a node the host resolves both variables
+`node dist/main.js`. On a node the controller composes the variables and the host supervises the
-and starts it like any other supervised workload.
+process like any other host-side workload (novox/hq to-be 38). As `node-tools` the same process is
+the console: MCP on `127.0.0.1:4270` (or `MESH_CONSOLE_LISTEN`). The container (`Dockerfile`) is how
+a module's own *service* may still be built; it is no longer how tools reach a node.
+
+## `mesh` — the tools for whoever is on a machine
+
+The same package carries the client (novox/hq design 25 §7, design 34): `mesh tools`, `mesh call
+<module>.<tool> [json]`, `mesh mcp` (an MCP server over stdio for a program a person starts) and
+`mesh serve` (the **console**: MCP over HTTP on a machine's loopback, started by the mesh as the
+`mesh-console` module on the credential in `MESH_BROKER_FILE` — novox/hq ADR 0152). `mesh serve`
+refuses to bind anything but loopback. With `--console <url>`, `tools` and `call` go through a console
+already on the machine and need no credential.
+
+The console announces six tools and reaches everything else by address (novox/hq ADR 0195):
+`mesh_overview` (the mesh's seats and machines), `mesh_machine` (one machine's seats and modules),
+`mesh_search` (a tool by words), `mesh_describe` (one tool's arguments), `mesh_call` (call one by
+address) and `mesh_runtimes` (which runtimes answered discovery: per runtime its machine, how long its
+answer took, its size in bytes, how many modules and tools it announced, whether it was shortened to
+fit the bus, when it was last heard — and who was expected and not heard).
+
+`mesh_search` also finds a tool by the shell command it replaces (novox/hq ADR 0245): each seat verb and
+module tool says what it replaces in the controller's records (`replaces`, read from the controller's
+`tools` and `modules` answers), so `journalctl -u x`, `systemctl status x` or `docker ps` puts the verb
+for it first, and says the command it matched as `instead_of`. A word also matches through a short table
+of the words agents use for the mesh's (`logs` finds the journal). Best first: a replaced command, then
+words in a name or a replaced command, then words in a description; seats before modules on a tie.
+
+Discovery asks the bus (ADR 0197): every runtime answers the NATS services protocol's `$SRV.PING` and
+`$SRV.INFO` with what it serves at that moment, and the console reads where the controller's records
+place each module. The console waits at least 750 ms, and up to 5 s for every runtime that answered
+PING to send what it serves — a large runtime's answer crossing the bus to a broker on another machine
+can arrive well after the rest. A runtime that said it is there and did not say what it serves, or
+that answered earlier and not now, is named: the console never calls a module missing, or on another
+machine, while a runtime that might serve it was not heard. A runtime whose answer outgrows the bus
+announces first-line descriptions, then none, and says so. A module may not name a tool of its own
+`tools`; the runtime refuses it at load.
 
 ## Verified
 
-`npm test` stands up LavinMQ (the mesh's broker) and proves the whole path over real AMQP: the
+`npm test` runs against a real NATS server with JetStream (`MESH_TEST_NATS`, see any test's header
-runtime serves a registered tool, a separate connection invokes it by name and gets the result, and
+for the one-line `docker run`) and proves the whole path over the wire: the runtime serves a
-an unknown tool is refused over the wire.
+registered tool, a separate connection invokes it by name and gets the result, an unknown tool is
+refused, a runtime serves exactly the subjects it is issued and re-serves on a new membership, and
+the node's runtime serves three modules' bundles on one credential — one of them broken, named and
+not fatal — with every seat verb answering where the membership put it.

dlxprobe.mjs

@@ -1,48 +0,0 @@
-import amqp from "amqplib";
-
-const PORT = process.argv[2];
-const MPORT = process.argv[3];
-const B = `http://127.0.0.1:${MPORT}`;
-const AUTH = "Basic " + Buffer.from("guest:guest").toString("base64");
-
-async function api(method, path, body) {
-  const r = await fetch(B + path, {
-    method,
-    headers: { "content-type": "application/json", authorization: AUTH },
-    body: body ? JSON.stringify(body) : undefined,
-  });
-  if (r.status >= 300 && r.status !== 404) throw new Error(`${method} ${path} -> ${r.status}`);
-}
-
-await api("PUT", "/api/exchanges/%2f/mesh.events.dead", { type: "topic", durable: true });
-await api("PUT", "/api/users/al", { password: "s", tags: "" });
-
-const Q = "anchor.al.events";
-const D = "mesh.events.dead";
-const q = Q.replace(/\./g, "\\.");
-const d = D.replace(/\./g, "\\.");
-
-// configure, write, read patterns per grant on the dead exchange
-const combos = {
-  "none":            { configure: `^${q}$`,          write: `^${q}$`,          read: `^${q}$` },
-  "read-dead":       { configure: `^${q}$`,          write: `^${q}$`,          read: `^(${q}|${d})$` },
-  "write-dead":      { configure: `^${q}$`,          write: `^(${q}|${d})$`,   read: `^${q}$` },
-  "configure-dead":  { configure: `^(${q}|${d})$`,   write: `^${q}$`,          read: `^${q}$` },
-  "read+write-dead": { configure: `^${q}$`,          write: `^(${q}|${d})$`,   read: `^(${q}|${d})$` },
-};
-
-let i = 0;
-for (const [label, perms] of Object.entries(combos)) {
-  await api("PUT", "/api/permissions/%2f/al", perms);
-  const queue = `${Q}.${i++}`; // fresh each time
-  try {
-    const c = await amqp.connect(`amqp://al:s@127.0.0.1:${PORT}/`);
-    const ch = await c.createChannel();
-    ch.on("error", () => {});
-    await ch.assertQueue(queue, { durable: true, deadLetterExchange: D });
-    console.log(`${label}: declare-with-DLX OK`);
-    await c.close();
-  } catch (e) {
-    console.log(`${label}: FAIL - ${String(e.message).slice(0, 70)}`);
-  }
-}

merge-check.sh

@@ -0,0 +1,55 @@
+#!/bin/sh
+# mesh-check-toolchain: go
+#
+# The tool runtime's own check (novox/hq ADR 0237 as amended): the second layer of a pull request's merge
+# check, `mesh/repo-check`, run by the build seat in the mesh's Go toolchain — and by hand.
+#
+# The gate — every machine of the facts snapshot composed with this change — is the build seat's first
+# layer (`mesh/merge-gate`), run because the mesh's module graph builds node-tools and mesh-tools from
+# here. This is the code's own: node-tools (Go) formatted, vetted and its suite, every test on a bus of its
+# own at the release the mesh runs (internal/meshtest), packages in parallel, under the race detector when
+# the toolchain has a C compiler.
+#
+# **Said, never passed silently**: the runtime's and the console's tests launch TypeScript and Python
+# bundles that import the mesh's own package (@novox/mesh-sdk), which comes from the package registry — and
+# a check of code nobody has approved is given no credential for it. Where node and that package are not
+# present those two packages are not tested here, and the TypeScript in node-tools/src neither.
+set -eu
+cd node-tools
+
+unformatted=$(gofmt -l cmd internal)
+if [ -n "$unformatted" ]; then
+	echo "not gofmt'd:"
+	echo "$unformatted"
+	exit 1
+fi
+CGO_ENABLED=0 go vet ./...
+
+packages=$(go list ./...)
+bundleless=""
+if ! command -v node >/dev/null 2>&1 || [ ! -d node_modules/@novox/mesh-sdk ]; then
+	echo "NOT TESTED HERE: internal/runtime and internal/console launch bundles that need node and @novox/mesh-sdk"
+	packages=$(printf '%s\n' "$packages" | grep -v -e '/internal/runtime$' -e '/internal/console$')
+	# What of the console launches no bundle runs anyway: how an address resolves (novox/hq issue 287),
+	# and how a search ranks (novox/hq ADR 0245), and what discovery heard and how a round that heard nothing is
+	# answered (novox/hq issue 554).
+	bundleless='^(TestASeatAndAModuleOfOneNameAreEachReached|TestSearch.*|TestASearchByCommandSaysWhatItReplaces|TestARuntimeThatAnswersLateIsFoundAndOneThatNeverDoesIsNamed|TestARuntimeHeardBeforeAndNotNowIsNamed|TestACallAfterARoundThatHeardNothingUsesWhatWasHeardBefore|TestAnAddressKnownOnlyFromAnEarlierAnswerSaysHowOld)$'
+	# And what of the runtime launches no bundle: how a bundle's seat traffic reaches the bus, what its
+	# environment holds, what a runtime on a module's own account serves (novox/hq ADR 0259), and that a write
+	# by compare-and-set loses no update under contention (novox/hq research 042), and a module's log verbs
+	# (novox/hq ADR 0297), and a key's history (novox/hq ADR 0307).
+	runtimeless='^(TestALogAnswersEachVerbOnTheBus|TestALogPageIsBoundedByItsBytes|TestAnAppendAtAStaleExpectIsRefusedAsALostUpdate|TestALogNotIssuedIsRefusedWithTheReason|TestWhatALogCannotHoldIsRefusedWithTheReason|TestALogRefusesAValueNamingACredential|TestAKeysHistoryIsEveryValueKeptOldestFirst|TestAKeysHistoryIsRefusedToAModuleNotIssuedTheState|TestARuntimeOnAModulesOwnAccountServesThatModuleAlone|TestNoBusWordReachesABundle|TestAToolCallNeverReachesASeatsEventAcceptOrProof|TestABundlesSeatTrafficGoesThroughItsModulesBus|TestALostCompareAndSetCarriesItsCode|TestTwoWritersIncrementingOneCounterOnTheBusLoseNoUpdate|TestAStaleWriteIsRefusedAndWritesNothing|TestACallOnTheCallerNamedSubjectReachesTheModuleWithItsCaller|TestTheSubjectThatNamesNoCallerStillWorksAndNamesNone)$'
+fi
+if command -v gcc >/dev/null 2>&1; then
+	CGO_ENABLED=1 go test -race -count=1 $packages
+else
+	echo "NOT RACE-CHECKED: the toolchain holds no C compiler; the suite runs without the race detector"
+	CGO_ENABLED=0 go test -count=1 $packages
+fi
+if [ -n "$bundleless" ]; then
+	CGO_ENABLED=0 go test -count=1 -run "$bundleless" ./internal/console
+fi
+if [ -n "${runtimeless:-}" ]; then
+	CGO_ENABLED=0 go test -count=1 -run "$runtimeless" ./internal/runtime
+fi
+echo "NOT TESTED HERE: node-tools/src (TypeScript) needs @novox/mesh-sdk from the package registry"

module.json

@@ -21,6 +21,11 @@
       {
         "arg": "NODE_BASE",
         "image": "node@sha256:48e4b67d85f87bd551df43704e24d252f56cc5f8e9718841aace50f19948f0f9"
+      },
+      {
+        "arg": "MESH_SDK",
+        "module": "mesh-sdk",
+        "artifact": "lib"
       }
     ]
   },

node-tools/README.md

@@ -0,0 +1,11 @@
+# node-tools
+
+The node's tool runtime as a module (novox/hq ADR 0175, to-be 38 WP3). Assigned to a machine, it is
+one process the host runs from this bundle, as the operator's account: it serves every assigned
+module's tools and every held seat's verbs on the bus, and answers MCP on the machine's loopback —
+the console (design 34). The controller composes the process (which bundles to load, where the
+credential is, whose machine it is); this manifest says only what the machine must have for it: the
+interpreter, a place for the credential, the loopback port, and leave to call every tool.
+
+The code is the `mesh-tools` package in this directory; the module at the repository root,
+`mesh-tools`, builds the images TypeScript bundles are compiled in. See the repository README.

node-tools/cmd/node-tools/main.go

@@ -0,0 +1,138 @@
+// node-tools — the node's tool runtime, in Go (novox/hq ADR 0175, ADR 0193; to-be 38 WP4d).
+//
+// One process per machine: it connects to the bus on the node's credential, launches every assigned
+// module's tools bundle and serves its tools and its seats' verbs; as the node-tools module — or
+// wherever MESH_CONSOLE_LISTEN says — it is also the console, MCP over HTTP on loopback.
+//
+//	MESH_BROKER_FILE       the credential the mesh sealed to this machine for the runtime
+//	MESH_TOOL_MODULES      <module>=<entrypoint>,… the bundles to launch
+//	MESH_TOOL_ENV          {"<module>": {"<word>": "<value>"}} what each is given (ADR 0192)
+//	MESH_OPERATOR_ACCOUNT  whose machine this is, and MESH_OPERATOR_HOME their home
+//	MESH_CONSOLE_LISTEN    where the console listens, overriding 127.0.0.1:4270
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"math/rand/v2"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/alive"
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/console"
+	"github.com/novox/mesh-tools/node-tools/internal/runtime"
+)
+
+// runtimeModule is the module that is the node's tool runtime; on its credential, serving is also
+// the console.
+const runtimeModule = "node-tools"
+
+// consoleListen is where the console listens when nothing says otherwise.
+const consoleListen = "127.0.0.1:4270"
+
+func main() {
+	log.SetFlags(0)
+	if len(os.Args) > 1 && os.Args[1] != "serve" {
+		fmt.Fprintf(os.Stderr, "node-tools: %q is not a mode; this runtime serves (novox/hq ADR 0193)\n", os.Args[1])
+		os.Exit(2)
+	}
+	cred := credential()
+	conn := connectPatiently(cred)
+
+	served, err := runtime.ServedModulesFrom(os.Getenv(runtime.ToolModules), cred.Module)
+	if err != nil {
+		log.Fatalf("node-tools: %v", err)
+	}
+	envs, err := runtime.TakeToolEnvs()
+	if err != nil {
+		log.Fatalf("node-tools: %v", err)
+	}
+	stop, err := runtime.Run(conn, served, envs, log.Printf)
+	if err != nil {
+		log.Fatalf("node-tools: %v", err)
+	}
+	// And says it is there (novox/hq to-be 45 S11): the machine's runtime, on its machine's name. A
+	// runtime on another credential — a module's own, in a test — is not the machine's.
+	stopSaying := func() {}
+	if cred.Module == runtimeModule && cred.Node != "" {
+		stopSaying = alive.Keep(conn, cred.Node, alive.Every, log.Printf)
+	}
+
+	listen := os.Getenv("MESH_CONSOLE_LISTEN")
+	if listen == "" && cred.Module == runtimeModule {
+		listen = consoleListen
+	}
+	var up *console.Listening
+	if listen != "" {
+		node := cred.Node
+		if node == "" {
+			node = "?"
+		}
+		who := node + "." + cred.Module
+		up, err = console.Serve(console.NewSurface(conn, who), listen)
+		if err != nil {
+			log.Fatalf("node-tools: %v", err)
+		}
+		log.Printf("mesh console listening on http://%s/mcp as %s", up.Address, who)
+	}
+
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
+	<-signals
+	stopSaying()
+	stop()
+	if up != nil {
+		_ = up.Close()
+	}
+	conn.Close()
+}
+
+// credential reads the credential the mesh delivered; a missing or unreadable one is a fault of
+// configuration, said and final.
+func credential() bus.Credential {
+	file := os.Getenv("MESH_BROKER_FILE")
+	if file == "" {
+		if url := os.Getenv("MESH_BROKER_URL"); url != "" {
+			return bus.Credential{URL: url, Module: runtimeModule}
+		}
+		fmt.Fprintln(os.Stderr, "node-tools: set MESH_BROKER_FILE (a sealed credential) or MESH_BROKER_URL — there is no broker to reach")
+		os.Exit(1)
+	}
+	raw, err := os.ReadFile(file)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "node-tools: cannot read the broker credential at %s: %v\n", file, err)
+		os.Exit(1)
+	}
+	var cred bus.Credential
+	if err := json.Unmarshal(raw, &cred); err != nil {
+		fmt.Fprintf(os.Stderr, "node-tools: cannot read the broker credential at %s: %v\n", file, err)
+		os.Exit(1)
+	}
+	if cred.URL == "" {
+		fmt.Fprintf(os.Stderr, "node-tools: %s carries no url — it is not a broker credential\n", file)
+		os.Exit(1)
+	}
+	return cred
+}
+
+// connectPatiently retries while the bus is merely not reachable yet — the normal case at startup —
+// and gives up at once on what waiting cannot fix (issue 058).
+func connectPatiently(cred bus.Credential) *bus.Conn {
+	for delay := 2 * time.Second; ; delay = min(delay*2, 30*time.Second) {
+		conn, err := bus.Connect(cred)
+		if err == nil {
+			return conn
+		}
+		if fatal := bus.Fatal(err); fatal != "" {
+			fmt.Fprintf(os.Stderr, "node-tools: %s — waiting will not fix this; giving up\n", fatal)
+			os.Exit(1)
+		}
+		wait := delay + time.Duration(rand.IntN(1000))*time.Millisecond
+		fmt.Fprintf(os.Stderr, "node-tools: the broker is not reachable yet (%v); retrying in %ds\n", err, int(wait.Round(time.Second)/time.Second))
+		time.Sleep(wait)
+	}
+}

node-tools/go.mod

@@ -0,0 +1,22 @@
+module github.com/novox/mesh-tools/node-tools
+
+go 1.26.0
+
+require (
+	github.com/nats-io/nats.go v1.54.0
+	golang.org/x/sys v0.48.0
+)
+
+require (
+	github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op // indirect
+	github.com/google/go-tpm v0.9.8 // indirect
+	github.com/klauspost/compress v1.20.0 // indirect
+	github.com/minio/highwayhash v1.0.4 // indirect
+	github.com/nats-io/jwt/v2 v2.8.1 // indirect
+	github.com/nats-io/nats-server/v2 v2.11.17 // indirect
+	github.com/nats-io/nkeys v0.4.16 // indirect
+	github.com/nats-io/nuid v1.0.1 // indirect
+	go.uber.org/automaxprocs v1.6.0 // indirect
+	golang.org/x/crypto v0.57.0 // indirect
+	golang.org/x/time v0.15.0 // indirect
+)

node-tools/go.sum

@@ -0,0 +1,27 @@
+github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
+github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
+github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=
+github.com/google/go-tpm v0.9.8/go.mod h1:h9jEsEECg7gtLis0upRBQU+GhYVH6jMjrFxI8u6bVUY=
+github.com/klauspost/compress v1.20.0 h1:a3C1ke2ohxFymNlb2HWAHjDeKCI90scRskErZkR0ezA=
+github.com/klauspost/compress v1.20.0/go.mod h1:LUdAzn7YLVvxLpc7y3V1m40wESHTgc1422pwwBSKYuI=
+github.com/minio/highwayhash v1.0.4 h1:asJizugGgchQod2ja9NJlGOWq4s7KsAWr5XUc9Clgl4=
+github.com/minio/highwayhash v1.0.4/go.mod h1:GGYsuwP/fPD6Y9hMiXuapVvlIUEhFhMTh0rxU3ik1LQ=
+github.com/nats-io/jwt/v2 v2.8.1 h1:V0xpGuD/N8Mi+fQNDynXohVvp7ZztevW5io8CUWlPmU=
+github.com/nats-io/jwt/v2 v2.8.1/go.mod h1:nWnOEEiVMiKHQpnAy4eXlizVEtSfzacZ1Q43LIRavZg=
+github.com/nats-io/nats-server/v2 v2.11.17 h1:GKEghcFK6A+aFx11Yf1LjgLC3txAwvyhnYzhBIQZA8I=
+github.com/nats-io/nats-server/v2 v2.11.17/go.mod h1:B1sFVz4StNosQ903ak4N1G01Fl/9f8e06mXpFIE2K24=
+github.com/nats-io/nats.go v1.54.0 h1:vsXoOxjHp/GmPUN+EcI7uOf/uB+iAP+kEsAFNQN0yzA=
+github.com/nats-io/nats.go v1.54.0/go.mod h1:y+DZoD1oBOYfZTU681eTUiUjI0vbqYGixNVFHcjHJ0k=
+github.com/nats-io/nkeys v0.4.16 h1:rd5oAuLOb8mnAycB0xleuEBNS1pVVnN0fv/FF34Eypg=
+github.com/nats-io/nkeys v0.4.16/go.mod h1:llLgWoI0o4z/Q57q2R1kHfmocyhGV6VG/U18Glg1Afs=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
+go.uber.org/automaxprocs v1.6.0 h1:O3y2/QNTOdbF+e/dpXNNW7Rx2hZ4sTIPyybbxyNqTUs=
+go.uber.org/automaxprocs v1.6.0/go.mod h1:ifeIMSnPZuznNm6jmdzmU3/bfk01Fe2fotchwEFJ8r8=
+golang.org/x/crypto v0.57.0 h1:3ZVCjf8Ggz7zneR/EHRVx68Ctf+2pmIMP2UFhh9cC6M=
+golang.org/x/crypto v0.57.0/go.mod h1:Fdz0i5U6CoizGwLda9DttjSk6qlZo25zYNtR+ycvuZA=
+golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
+golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
+golang.org/x/time v0.15.0 h1:bbrp8t3bGUeFOx08pvsMYRTCVSMk89u4tKbNOZbp88U=
+golang.org/x/time v0.15.0/go.mod h1:Y4YMaQmXwGQZoFaVFk4YpCt4FLQMYKZe9oeV/f4MSno=

node-tools/internal/alive/alive.go

@@ -0,0 +1,80 @@
+// Package alive is the node tools saying they are there (novox/hq to-be 45 §3, S11).
+//
+// **A machine heard and its runtime gone is a machine nobody can ask anything.** The node-engine says
+// every minute that the machine is there; nothing said whether the runtime serving every module's
+// tools and every held seat's verbs was. Now it says so too, on its own subject, every interval, with
+// the interval — the controller's watchdog raises `tools-silent` after three missed — and its build.
+// Core NATS, kept by nobody, as the host's heartbeat: a lost one is the next one.
+package alive
+
+import (
+	"encoding/json"
+	"runtime/debug"
+	"sync"
+	"time"
+)
+
+// Every is how often the runtime says it is there.
+const Every = 60 * time.Second
+
+// Subject is where one machine's node tools say it.
+func Subject(node string) string { return "mesh.control." + node + ".tools-alive" }
+
+// Beat is what is said: the machine, the interval, and the build.
+type Beat struct {
+	Node            string `json:"node"`
+	IntervalSeconds int    `json:"interval_seconds"`
+	Version         string `json:"version,omitempty"`
+}
+
+// Sayer publishes one message, kept by nobody.
+type Sayer interface {
+	Say(subject string, body []byte) error
+}
+
+// Version is this build's commit, as the toolchain stamped it; empty when it did not.
+func Version() string {
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return ""
+	}
+	for _, s := range info.Settings {
+		if s.Key == "vcs.revision" {
+			return s.Value
+		}
+	}
+	return ""
+}
+
+// Keep says the runtime is there now and every interval until the returned function is called. A
+// heartbeat that cannot be said is logged when that starts and when it stops — not every minute.
+func Keep(bus Sayer, node string, every time.Duration, logf func(string, ...any)) func() {
+	body, _ := json.Marshal(Beat{Node: node, IntervalSeconds: int(every / time.Second), Version: Version()})
+	done := make(chan struct{})
+	var once sync.Once
+	go func() {
+		failing := ""
+		tick := time.NewTicker(every)
+		defer tick.Stop()
+		for {
+			why := ""
+			if err := bus.Say(Subject(node), body); err != nil {
+				why = err.Error()
+			}
+			if why != failing {
+				if why != "" {
+					logf("node-tools: could not say this runtime is there — the mesh will call it silent: %s", why)
+				} else {
+					logf("node-tools: says again that this runtime is there")
+				}
+				failing = why
+			}
+			select {
+			case <-done:
+				return
+			case <-tick.C:
+			}
+		}
+	}()
+	return func() { once.Do(func() { close(done) }) }
+}

node-tools/internal/alive/alive_test.go

@@ -0,0 +1,74 @@
+package alive
+
+import (
+	"encoding/json"
+	"errors"
+	"sync"
+	"testing"
+	"time"
+)
+
+type said struct {
+	mu   sync.Mutex
+	subs []string
+	body [][]byte
+	fail error
+}
+
+func (s *said) Say(subject string, body []byte) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.fail != nil {
+		return s.fail
+	}
+	s.subs, s.body = append(s.subs, subject), append(s.body, body)
+	return nil
+}
+
+func (s *said) count() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return len(s.subs)
+}
+
+// **The runtime says it is there at once and every interval, as its machine, with the interval**: the
+// controller's bound is three of them (to-be 45 S11).
+func TestTheRuntimeSaysItIsThereEveryInterval(t *testing.T) {
+	s := &said{}
+	stop := Keep(s, "anchor", 20*time.Millisecond, t.Logf)
+	time.Sleep(70 * time.Millisecond)
+	stop()
+	stop()
+	if n := s.count(); n < 3 {
+		t.Fatalf("said %d times in three intervals", n)
+	}
+	var beat Beat
+	if err := json.Unmarshal(s.body[0], &beat); err != nil || beat.Node != "anchor" || beat.IntervalSeconds != 0 ||
+		s.subs[0] != "mesh.control.anchor.tools-alive" {
+		t.Fatalf("%s on %s: %v", s.body[0], s.subs[0], err)
+	}
+	n := s.count()
+	time.Sleep(50 * time.Millisecond)
+	if s.count() != n {
+		t.Fatal("said after it was stopped")
+	}
+}
+
+// **A heartbeat the bus will not take is said once, and again when it is taken**: not a line a minute.
+func TestAHeartbeatThatCannotBeSaidIsLoggedOnce(t *testing.T) {
+	s := &said{fail: errors.New("permissions violation")}
+	var mu sync.Mutex
+	var lines []string
+	stop := Keep(s, "anchor", 10*time.Millisecond, func(f string, a ...any) {
+		mu.Lock()
+		lines = append(lines, f)
+		mu.Unlock()
+	})
+	time.Sleep(60 * time.Millisecond)
+	stop()
+	mu.Lock()
+	defer mu.Unlock()
+	if len(lines) != 1 {
+		t.Fatalf("logged %d lines for one failure", len(lines))
+	}
+}

node-tools/internal/announce/announce.go

@@ -0,0 +1,472 @@
+// Package announce answers the NATS services protocol's discovery for what a runtime serves, and
+// gathers the answers (novox/hq ADR 0197).
+//
+// A runtime does not re-serve its tools through a services library: serving is unchanged. It answers
+// `$SRV.PING`, `$SRV.INFO` and `$SRV.STATS` — and the same followed by its service name, and by its
+// name and id — in the format NATS's own tools read, with what it is serving at the moment it is
+// asked. One service per runtime process: the bus admits one reply per request from each responder,
+// so a runtime serving many modules and seats answers once, one endpoint per tool per subject, and
+// says in each endpoint's metadata which module, seat, scope and machine it is.
+package announce
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"strings"
+	"time"
+
+	"github.com/nats-io/nats.go/micro"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// Version is the announced service version (semver, as the protocol requires).
+const Version = "0.1.0"
+
+// Window is how long the console gathers discovery answers at the least: every instance answers one
+// request, and how many will is what is being found out.
+var Window = 750 * time.Millisecond
+
+// Patience is how long the console waits, at the most, for the full answer of a service that has
+// said it is there. **A fixed window lost the largest runtime** (2026-10-05): the laptop's answer —
+// 48 modules, 341 endpoints, 164 kB — went up to the broker on another machine and back, arrived
+// last every time (a median of 365 ms, one in 25 after 813 ms on a quiet link, later still while the
+// runtime re-served), and when it missed the 750 ms window the console said its modules ran nowhere.
+// A PING answer is a hundred bytes and arrives at once, so who is there is known early; what each
+// serves is waited for until it arrives or this passes, and a service that never sends it is named.
+var Patience = 5 * time.Second
+
+// Digest is the PING answer's metadata key for a digest of what the instance serves now: a console
+// that holds the answer of that digest does not ask for it again (novox/hq issue 554). Every round
+// pulled every runtime's whole announcement — some 880 kB, every five seconds while a session works —
+// to the laptop, and the hundred-byte PING answers queued behind it.
+const Digest = "digest"
+
+// Shortened is the service metadata key a runtime sets when its announcement was cut to fit the bus.
+const Shortened = "shortened"
+
+// Kinds of endpoint.
+const (
+	KindTool = "tool" // a module's own tool
+	KindSeat = "seat" // a seat's verb, served by the module holding it
+)
+
+// Endpoint is one tool served on one subject, as it is announced.
+type Endpoint struct {
+	Kind            string
+	Module          string // the module whose code answers
+	Tool            string // the tool's or the verb's name
+	Seat            string // for a seat's verb
+	Scope           string // "mesh" or "node", for a seat's verb
+	Node            string
+	Description     string
+	Schema          json.RawMessage
+	Interchangeable bool
+	Subject         string
+	Queue           string
+}
+
+// Name is the endpoint's name as the protocol allows it — letters, digits, `-` and `_` — the
+// prefix and the tool joined by `__`; the metadata, not the name, is what identifies it.
+func (e Endpoint) Name() string {
+	prefix := e.Module
+	if e.Kind == KindSeat {
+		prefix = e.Seat
+	}
+	return clean(prefix) + "__" + clean(e.Tool)
+}
+
+func clean(s string) string {
+	var b strings.Builder
+	for _, r := range s {
+		if r == '-' || r == '_' || (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') {
+			b.WriteRune(r)
+		} else {
+			b.WriteRune('_')
+		}
+	}
+	return b.String()
+}
+
+func (e Endpoint) info() micro.EndpointInfo {
+	md := map[string]string{
+		"kind": e.Kind, "module": e.Module, "tool": e.Tool, "node": e.Node,
+		"description": e.Description, "interchangeable": boolWord(e.Interchangeable),
+	}
+	// **A seat's verb carries its schema; a module's tool does not.** Every tool's schema, once per
+	// subject it answers on, made a runtime's one answer outgrow the bus's largest message (1 MiB) once
+	// machines served a couple of hundred tools — and the answer that cannot be sent is silence: the
+	// machine vanished from discovery (2026-10-04). A module's tool's schema is asked of the runtime that
+	// serves it when a person describes it (its `tools` verb); a seat's verbs are few, and a seat has no
+	// `tools` verb of its own to ask.
+	if e.Kind == KindSeat {
+		schema := strings.TrimSpace(string(e.Schema))
+		if schema == "" || schema == "null" {
+			schema = "{}"
+		}
+		md["schema"] = schema
+	}
+	if e.Kind == KindSeat {
+		md["seat"] = e.Seat
+		md["scope"] = e.Scope
+	}
+	return micro.EndpointInfo{Name: e.Name(), Subject: e.Subject, QueueGroup: e.Queue, Metadata: md}
+}
+
+func boolWord(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}
+
+// Service is who answers: the runtime's name, its instance, and a word about it.
+type Service struct {
+	Name        string
+	ID          string
+	Description string
+	Metadata    map[string]string
+}
+
+func (s Service) identity() micro.ServiceIdentity {
+	md := s.Metadata
+	if md == nil {
+		md = map[string]string{}
+	}
+	return micro.ServiceIdentity{Name: s.Name, ID: s.ID, Version: Version, Metadata: md}
+}
+
+// Info is the info_response for these endpoints.
+func Info(s Service, endpoints []Endpoint) micro.Info {
+	out := micro.Info{ServiceIdentity: s.identity(), Type: micro.InfoResponseType,
+		Description: s.Description, Endpoints: []micro.EndpointInfo{}}
+	for _, e := range endpoints {
+		out.Endpoints = append(out.Endpoints, e.info())
+	}
+	return out
+}
+
+// Serve answers discovery for one service until stopped, asking `current` for its endpoints each
+// time — so what is announced is what is served now, re-served memberships included.
+func Serve(conn *bus.Conn, s Service, current func() []Endpoint) (func(), error) {
+	started := time.Now().UTC()
+	answer := func(subject string, _ []byte) []byte {
+		parts := strings.Split(subject, ".")
+		if len(parts) < 2 || parts[0] != "$SRV" {
+			return nil
+		}
+		if len(parts) >= 3 && parts[2] != s.Name {
+			return nil // another service's
+		}
+		if len(parts) >= 4 && parts[3] != s.ID {
+			return nil // another instance's
+		}
+		var v any
+		switch parts[1] {
+		case "PING":
+			id := s.identity()
+			md := map[string]string{}
+			for k, v := range id.Metadata {
+				md[k] = v
+			}
+			md[Digest] = DigestOf(Info(s, current()))
+			id.Metadata = md
+			v = micro.Ping{ServiceIdentity: id, Type: micro.PingResponseType}
+		case "INFO":
+			v = Info(s, current())
+		case "STATS":
+			st := micro.Stats{ServiceIdentity: s.identity(), Type: micro.StatsResponseType, Started: started,
+				Endpoints: []*micro.EndpointStats{}}
+			for _, e := range current() {
+				st.Endpoints = append(st.Endpoints, &micro.EndpointStats{Name: e.Name(), Subject: e.Subject, QueueGroup: e.Queue})
+			}
+			v = st
+		default:
+			return nil
+		}
+		body, err := json.Marshal(v)
+		if err != nil {
+			return nil
+		}
+		// Too large for the bus is no answer at all, and was silent: shorten every description to its
+		// first line and say so, rather than vanish; still too large, leave descriptions out.
+		if limit := conn.MaxPayload(); limit > 0 && int64(len(body)) > limit {
+			if info, ok := v.(micro.Info); ok {
+				body = shorten(conn.Logf, info, body, limit)
+			}
+		}
+		return body
+	}
+	var stops []func()
+	for _, verb := range []string{"PING", "INFO", "STATS"} {
+		// Exactly the questions asked of every service and of this one by name and instance — what the
+		// grants allow (novox/hq ADR 0197). A wildcard is refused by the bus.
+		for _, subject := range []string{"$SRV." + verb, "$SRV." + verb + "." + s.Name, "$SRV." + verb + "." + s.Name + "." + s.ID} {
+			stop, err := conn.Raw(subject, answer)
+			if err != nil {
+				for _, st := range stops {
+					st()
+				}
+				return func() {}, err
+			}
+			stops = append(stops, stop)
+		}
+	}
+	return func() {
+		for _, st := range stops {
+			st()
+		}
+	}, nil
+}
+
+// DigestOf is a digest of an info_response: equal for equal announcements, whatever the moment.
+func DigestOf(i micro.Info) string {
+	body, err := json.Marshal(i)
+	if err != nil {
+		return ""
+	}
+	sum := sha256.Sum256(body)
+	return hex.EncodeToString(sum[:12])
+}
+
+// shorten is an info_response cut to fit the bus: descriptions to their first line, then none, the
+// service's metadata saying which (so discovery can tell a person what it was given).
+func shorten(logf func(string, ...any), info micro.Info, body []byte, limit int64) []byte {
+	md := map[string]string{}
+	for k, v := range info.Metadata {
+		md[k] = v
+	}
+	info.Metadata = md
+	for _, step := range []string{"descriptions cut to their first line", "descriptions left out"} {
+		for i := range info.Endpoints {
+			e := info.Endpoints[i].Metadata
+			if step == "descriptions left out" {
+				delete(e, "description")
+			} else {
+				e["description"] = firstLine(e["description"])
+			}
+		}
+		md[Shortened] = step
+		shorter, err := json.Marshal(info)
+		if err != nil {
+			return body
+		}
+		logf("[mesh-tools] what this runtime serves is %d bytes, beyond the bus's %d; announced with %s (%d bytes)",
+			len(body), limit, step, len(shorter))
+		if int64(len(shorter)) <= limit {
+			return shorter
+		}
+		body = shorter
+	}
+	return body
+}
+
+// Heard is one service instance's answer to discovery: what it serves, how long it took to arrive,
+// and how large it was.
+type Heard struct {
+	Info      micro.Info
+	Took      time.Duration
+	Bytes     int
+	Shortened string // why its descriptions are not whole, or ""
+	// Digest is the digest its PING gave for this answer, or "" when it gave none.
+	Digest string
+	// Reused is true when the instance's PING said it serves what the console already held, so its
+	// announcement was not asked for again; Took is then how long its PING took.
+	Reused bool
+}
+
+// Machine is the machine an instance runs on: its metadata's, or the one its endpoints name.
+func (h Heard) Machine() string {
+	if n := h.Info.Metadata["node"]; n != "" {
+		return n
+	}
+	for _, e := range h.Info.Endpoints {
+		if n := e.Metadata["node"]; n != "" {
+			return n
+		}
+	}
+	return ""
+}
+
+// Instance names one service instance.
+type Instance struct {
+	Name    string
+	ID      string
+	Machine string
+}
+
+// Discovery is what one round of discovery heard, and who said it was there but did not say what it
+// serves in time.
+type Discovery struct {
+	At     time.Time
+	Waited time.Duration
+	Heard  []Heard
+	Silent []Instance
+	// Pinged is how many PING answers arrived.
+	Pinged int
+}
+
+// Empty is a round in which nothing arrived at all, not even a PING: no answer about the mesh, but a
+// round that failed (novox/hq issue 554).
+func (d Discovery) Empty() bool { return d.Pinged == 0 && len(d.Heard) == 0 }
+
+// Known is the announcement a console already holds for an instance at this digest, if any.
+type Known func(name, id, digest string) (Heard, bool)
+
+// Gather asks every service on the bus who it is (`$SRV.PING`), and each instance that answers what it
+// serves (`$SRV.INFO.<name>.<id>`) unless its PING's digest is one `known` holds; it waits at least the
+// window and at most the patience: until at least one instance answered PING and every instance that
+// did has said what it serves. A round in which no PING arrives within the window is not taken as the
+// mesh's answer that nothing is there (novox/hq issue 554): it waits on, up to the patience. An answer
+// that is not the protocol's is skipped.
+func Gather(conn *bus.Conn, known Known) (Discovery, error) {
+	start := time.Now()
+	d := Discovery{At: start.UTC()}
+	pings, stopPings, err := conn.Collect("$SRV.PING", nil)
+	if err != nil {
+		return d, err
+	}
+	defer stopPings()
+	infos, askInfo, stopInfos, err := conn.Collector("$SRV.INFO")
+	if err != nil {
+		return d, err
+	}
+	defer stopInfos()
+
+	type key struct{ name, id string }
+	pinged := map[key]int{}
+	answered := map[key]int{}
+	where := map[key]string{}
+	digest := map[key]string{}
+	asked := map[key]bool{}
+	reused := map[key]int{} // index in d.Heard of an answer held already
+	var order []key
+	complete := func() bool {
+		if len(pinged) == 0 {
+			return false // nobody said they are there: not an answer, a round that has not arrived
+		}
+		for k, n := range pinged {
+			if answered[k] < n {
+				return false
+			}
+		}
+		return true
+	}
+	ask := func(k key) {
+		if asked[k] {
+			return
+		}
+		asked[k] = true
+		if err := askInfo("$SRV.INFO."+k.name+"."+k.id, nil); err != nil {
+			conn.Logf("[mesh-tools] discovery could not ask %s/%s what it serves: %v", k.name, k.id, err)
+		}
+	}
+	least := time.NewTimer(Window)
+	defer least.Stop()
+	most := time.NewTimer(Patience)
+	defer most.Stop()
+	windowOver := false
+	for {
+		select {
+		case a := <-pings:
+			var p micro.Ping
+			if json.Unmarshal(a.Data, &p) != nil || p.Type != micro.PingResponseType {
+				continue
+			}
+			d.Pinged++
+			k := key{p.Name, p.ID}
+			_, seen := pinged[k]
+			if !seen {
+				order = append(order, k)
+			}
+			pinged[k]++
+			if where[k] == "" {
+				where[k] = p.Metadata["node"]
+			}
+			if seen {
+				// Two instances under one name and id: what each serves is asked of both, never assumed.
+				if i, ok := reused[k]; ok {
+					d.Heard = append(d.Heard[:i], d.Heard[i+1:]...)
+					for kk, j := range reused {
+						if j > i {
+							reused[kk] = j - 1
+						}
+					}
+					delete(reused, k)
+					answered[k]--
+				}
+				ask(k)
+				continue
+			}
+			digest[k] = p.Metadata[Digest]
+			if h, ok := heldAt(known, k.name, k.id, digest[k]); ok {
+				h.Took, h.Reused, h.Digest = a.At.Sub(start), true, digest[k]
+				reused[k] = len(d.Heard)
+				d.Heard = append(d.Heard, h)
+				answered[k]++
+				break
+			}
+			ask(k)
+		case a := <-infos:
+			var i micro.Info
+			if json.Unmarshal(a.Data, &i) != nil || i.Type != micro.InfoResponseType {
+				continue
+			}
+			k := key{i.Name, i.ID}
+			answered[k]++
+			d.Heard = append(d.Heard, Heard{Info: i, Took: a.At.Sub(start), Bytes: len(a.Data), Shortened: i.Metadata[Shortened],
+				Digest: digest[k]})
+		case <-least.C:
+			windowOver = true
+		case <-most.C:
+			d.Waited = time.Since(start)
+			for _, k := range order {
+				if answered[k] < pinged[k] {
+					d.Silent = append(d.Silent, Instance{Name: k.name, ID: k.id, Machine: where[k]})
+				}
+			}
+			return d, nil
+		}
+		if windowOver && complete() {
+			d.Waited = time.Since(start)
+			return d, nil
+		}
+	}
+}
+
+// heldAt is the answer `known` holds for an instance at this digest; never for a PING without one.
+func heldAt(known Known, name, id, digest string) (Heard, bool) {
+	if known == nil || digest == "" {
+		return Heard{}, false
+	}
+	return known(name, id, digest)
+}
+
+// Endpoints reads an info_response's endpoints back into what they announce.
+func Endpoints(i micro.Info) []Endpoint {
+	var out []Endpoint
+	for _, e := range i.Endpoints {
+		md := e.Metadata
+		out = append(out, Endpoint{
+			Kind: md["kind"], Module: md["module"], Tool: md["tool"], Seat: md["seat"], Scope: md["scope"],
+			Node: md["node"], Description: md["description"], Schema: json.RawMessage(md["schema"]),
+			Interchangeable: md["interchangeable"] == "true", Subject: e.Subject, Queue: e.QueueGroup,
+		})
+	}
+	return out
+}
+
+// firstLine is a description's first sentence or line, at most 160 characters.
+func firstLine(s string) string {
+	if i := strings.IndexAny(s, "\n"); i >= 0 {
+		s = s[:i]
+	}
+	if i := strings.Index(s, ". "); i >= 0 {
+		s = s[:i+1]
+	}
+	if len(s) > 160 {
+		s = s[:157] + "..."
+	}
+	return s
+}

node-tools/internal/announce/announce_test.go

@@ -0,0 +1,54 @@
+package announce
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+// What a machine serves fits the bus's largest message (1 MiB) with room to spare at several hundred
+// tools: a module's tool is announced without its schema, which made a machine with ~200 tools outgrow it
+// and vanish from discovery (2026-10-04). A seat's verb keeps its schema.
+func TestAMachinesAnnouncementFitsTheBusAtSeveralHundredTools(t *testing.T) {
+	schema := json.RawMessage(`{"type":"object","properties":{` + strings.Repeat(`"field_with_a_long_name":{"type":"string","description":"a description of what this argument means, long enough to matter"},`, 12) + `"last":{"type":"string"}}}`)
+	description := strings.Repeat("A tool that does something useful, described at the length the catalogue's tools are. ", 3)
+	var endpoints []Endpoint
+	for i := 0; i < 400; i++ {
+		for _, subject := range []string{fmt.Sprintf("mesh.mod.m%d.tool.t", i), fmt.Sprintf("mesh.mod.m%d.tool.t.laptop", i)} {
+			endpoints = append(endpoints, Endpoint{Kind: KindTool, Module: fmt.Sprintf("m%d", i), Tool: "t", Node: "laptop",
+				Description: description, Schema: schema, Subject: subject})
+		}
+	}
+	endpoints = append(endpoints, Endpoint{Kind: KindSeat, Module: "m0", Tool: "verb", Seat: "a-seat", Scope: "mesh",
+		Description: "a verb", Schema: schema, Subject: "mesh.seat.a-seat.tool.verb"})
+	body, err := json.Marshal(Info(Service{Name: "node-tools", ID: "laptop"}, endpoints))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(body) > 1<<20 {
+		t.Fatalf("400 tools announce %d bytes, beyond the bus's 1 MiB", len(body))
+	}
+	t.Logf("400 tools on two subjects each announce %d bytes", len(body))
+	back := Endpoints(Info(Service{Name: "node-tools", ID: "laptop"}, endpoints))
+	if len(back[0].Schema) != 0 {
+		t.Fatalf("a module's tool still carries its schema: %s", back[0].Schema)
+	}
+	if seat := back[len(back)-1]; !strings.Contains(string(seat.Schema), "field_with_a_long_name") {
+		t.Fatalf("a seat's verb lost its schema: %s", seat.Schema)
+	}
+	withSchemas := 0
+	for range endpoints {
+		withSchemas += len(schema) * 2 // escaped inside a string
+	}
+	t.Logf("with every schema it would have been over %d bytes", len(body)+withSchemas)
+}
+
+func TestFirstLineShortensADescription(t *testing.T) {
+	if got := firstLine("One thing. And more after it."); got != "One thing." {
+		t.Fatalf("%q", got)
+	}
+	if got := firstLine(strings.Repeat("x", 300)); len(got) != 160 {
+		t.Fatalf("%d", len(got))
+	}
+}

node-tools/internal/announce/empty_round_test.go

@@ -0,0 +1,126 @@
+package announce
+
+import (
+	"encoding/json"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go/micro"
+)
+
+// novox/hq issue 554: the laptop's console took a round in which not even a PING arrived within the
+// 750 ms window as the mesh's answer that nothing is there, and refused every seat and module call. A
+// PING that arrives after the window is waited for, up to the patience.
+func TestARoundWaitsForAPingThatArrivesAfterTheWindow(t *testing.T) {
+	was := Patience
+	Patience = 2500 * time.Millisecond
+	t.Cleanup(func() { Patience = was })
+
+	late := connect(t, "node-tools", "laptop")
+	s := Service{Name: "node-tools", ID: "laptop", Metadata: map[string]string{"node": "laptop"}}
+	ping, _ := json.Marshal(micro.Ping{ServiceIdentity: s.identity(), Type: micro.PingResponseType})
+	stop, err := late.Raw("$SRV.PING", func(string, []byte) []byte { time.Sleep(Window + 300*time.Millisecond); return ping })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	body, _ := json.Marshal(Info(s, []Endpoint{{Kind: KindTool, Module: "slack", Tool: "slack_check", Node: "laptop", Subject: "mesh.mod.slack.tool.slack_check.laptop"}}))
+	for _, subject := range []string{"$SRV.INFO", "$SRV.INFO.node-tools.laptop"} {
+		stop, err := late.Raw(subject, func(string, []byte) []byte { return body })
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+	late.Flush()
+
+	d, err := Gather(connect(t, "console", "laptop"), nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if d.Empty() || len(d.Heard) != 1 || d.Heard[0].Machine() != "laptop" {
+		t.Fatalf("a PING after the window was not waited for: waited %s, pinged %d, heard %+v", d.Waited, d.Pinged, d.Heard)
+	}
+	if d.Waited < Window || d.Waited >= Patience {
+		t.Errorf("waited %s; the PING came after %s and patience is %s", d.Waited, Window+300*time.Millisecond, Patience)
+	}
+}
+
+// A round in which nothing at all arrives is said to be empty, after the patience — not answered as an
+// empty mesh at the window.
+func TestARoundThatHearsNothingIsEmptyAfterThePatience(t *testing.T) {
+	was := Patience
+	Patience = 1500 * time.Millisecond
+	t.Cleanup(func() { Patience = was })
+	d, err := Gather(connect(t, "console", "laptop"), nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !d.Empty() || d.Waited < Patience {
+		t.Errorf("empty %v after %s (patience %s)", d.Empty(), d.Waited, Patience)
+	}
+}
+
+// What a runtime announces is fetched again only when its PING's digest changed: every round pulled
+// some 880 kB of announcements to the laptop, and the PING answers queued behind them (issue 554).
+func TestAnUnchangedAnnouncementIsNotFetchedAgain(t *testing.T) {
+	runtime := connect(t, "node-tools", "desk")
+	var endpoints atomic.Value
+	endpoints.Store([]Endpoint{{Kind: KindTool, Module: "alpha", Tool: "one", Node: "desk", Subject: "mesh.mod.alpha.tool.one.desk"}})
+	stop, err := Serve(runtime, Service{Name: "node-tools", ID: "desk", Metadata: map[string]string{"node": "desk"}},
+		func() []Endpoint { return endpoints.Load().([]Endpoint) })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	runtime.Flush()
+	// Every request for what desk serves, counted where it is answered.
+	var asked atomic.Int32
+	spy := connect(t, "node-tools", "spy")
+	for _, subject := range []string{"$SRV.INFO", "$SRV.INFO.node-tools", "$SRV.INFO.node-tools.desk"} {
+		stop, err := spy.Raw(subject, func(string, []byte) []byte { asked.Add(1); return nil })
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+	spy.Flush()
+
+	console := connect(t, "console", "laptop")
+	first, err := Gather(console, nil)
+	if err != nil || len(first.Heard) != 1 || first.Heard[0].Digest == "" || first.Heard[0].Reused {
+		t.Fatalf("first round: %v %+v", err, first.Heard)
+	}
+	if asked.Load() != 1 {
+		t.Errorf("the first round asked what desk serves %d time(s)", asked.Load())
+	}
+	held := first.Heard[0]
+	known := func(name, id, digest string) (Heard, bool) {
+		if name == held.Info.Name && id == held.Info.ID && digest == held.Digest {
+			return held, true
+		}
+		return Heard{}, false
+	}
+	asked.Store(0)
+	second, err := Gather(console, known)
+	if err != nil || len(second.Heard) != 1 || !second.Heard[0].Reused || len(Endpoints(second.Heard[0].Info)) != 1 {
+		t.Fatalf("an unchanged announcement: %v %+v", err, second.Heard)
+	}
+	if asked.Load() != 0 {
+		t.Errorf("an unchanged announcement was asked for %d time(s)", asked.Load())
+	}
+
+	endpoints.Store([]Endpoint{
+		{Kind: KindTool, Module: "alpha", Tool: "one", Node: "desk", Subject: "mesh.mod.alpha.tool.one.desk"},
+		{Kind: KindTool, Module: "alpha", Tool: "two", Node: "desk", Subject: "mesh.mod.alpha.tool.two.desk"},
+	})
+	third, err := Gather(console, known)
+	if err != nil || len(third.Heard) != 1 || third.Heard[0].Reused || len(Endpoints(third.Heard[0].Info)) != 2 ||
+		third.Heard[0].Digest == held.Digest {
+		t.Fatalf("a changed announcement was not fetched: %v %+v", err, third.Heard)
+	}
+	if asked.Load() != 1 {
+		t.Errorf("a changed announcement was asked for %d time(s)", asked.Load())
+	}
+}

node-tools/internal/announce/gather_test.go

@@ -0,0 +1,160 @@
+package announce
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go/micro"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+func connect(t *testing.T, module, node string) *bus.Conn {
+	t.Helper()
+	c, err := bus.Connect(bus.Credential{URL: mt.URL(t), Module: module, Node: node})
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.Logf = func(string, ...any) {}
+	t.Cleanup(c.Close)
+	return c
+}
+
+// lagging answers PING at once and INFO after `lag` — or never, with a negative lag: a runtime whose
+// one large answer is slow to cross the bus, as the laptop's was (2026-10-05).
+func lagging(t *testing.T, conn *bus.Conn, s Service, lag time.Duration, endpoints []Endpoint) {
+	t.Helper()
+	ping, _ := json.Marshal(micro.Ping{ServiceIdentity: s.identity(), Type: micro.PingResponseType})
+	stop, err := conn.Raw("$SRV.PING", func(string, []byte) []byte { return ping })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	// Asked of every service, and of this instance by name and id — as discovery asks it (issue 554).
+	info := func(string, []byte) []byte {
+		if lag < 0 {
+			return nil
+		}
+		time.Sleep(lag)
+		body, _ := json.Marshal(Info(s, endpoints))
+		return body
+	}
+	for _, subject := range []string{"$SRV.INFO", "$SRV.INFO." + s.Name + "." + s.ID} {
+		stop, err := conn.Raw(subject, info)
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+	conn.Flush()
+}
+
+// A runtime whose answer arrives after the window is waited for, because it said it was there; one
+// that never says what it serves is named, not dropped. With the fixed 750 ms window the laptop's
+// modules were said to run nowhere whenever its answer was late (2026-10-05).
+func TestDiscoveryWaitsForEveryRuntimeThatSaidItIsThere(t *testing.T) {
+	was := Patience
+	Patience = 2500 * time.Millisecond
+	t.Cleanup(func() { Patience = was })
+
+	fast := connect(t, "node-tools", "desk")
+	stopFast, err := Serve(fast, Service{Name: "node-tools", ID: "desk", Metadata: map[string]string{"node": "desk"}}, func() []Endpoint {
+		return []Endpoint{{Kind: KindTool, Module: "alpha", Tool: "one", Node: "desk", Subject: "mesh.mod.alpha.tool.one.desk"}}
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopFast)
+	fast.Flush()
+	slow := connect(t, "node-tools", "laptop")
+	lagging(t, slow, Service{Name: "node-tools", ID: "laptop", Metadata: map[string]string{"node": "laptop"}}, Window+400*time.Millisecond,
+		[]Endpoint{{Kind: KindTool, Module: "slack", Tool: "slack_check", Node: "laptop", Subject: "mesh.mod.slack.tool.slack_check.laptop"}})
+	mute := connect(t, "node-tools", "sleeper")
+	lagging(t, mute, Service{Name: "node-tools", ID: "sleeper", Metadata: map[string]string{"node": "sleeper"}}, -1, nil)
+
+	asker := connect(t, "console", "desk")
+	start := time.Now()
+	d, err := Gather(asker, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	took := time.Since(start)
+
+	heard := map[string]Heard{}
+	for _, h := range d.Heard {
+		heard[h.Info.ID] = h
+	}
+	if h, ok := heard["laptop"]; !ok {
+		t.Fatalf("the slow runtime was not heard: %+v", d.Heard)
+	} else if h.Took <= Window || h.Machine() != "laptop" || h.Bytes == 0 {
+		t.Errorf("the slow runtime's answer: took %s (window %s), machine %q, %d bytes", h.Took, Window, h.Machine(), h.Bytes)
+	}
+	if _, ok := heard["desk"]; !ok {
+		t.Errorf("the fast runtime was not heard: %+v", d.Heard)
+	}
+	if len(d.Silent) != 1 || d.Silent[0].ID != "sleeper" || d.Silent[0].Machine != "sleeper" {
+		t.Errorf("the runtime that never said what it serves is not named: %+v", d.Silent)
+	}
+	if took < Patience || took > Patience+time.Second {
+		t.Errorf("waited %s with a silent runtime; patience is %s", took, Patience)
+	}
+}
+
+// With nobody slow, discovery takes the window and no longer.
+func TestDiscoveryDoesNotWaitWhenEveryoneAnswered(t *testing.T) {
+	fast := connect(t, "node-tools", "desk")
+	stop, err := Serve(fast, Service{Name: "node-tools", ID: "desk"}, func() []Endpoint { return nil })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	fast.Flush()
+	start := time.Now()
+	d, err := Gather(connect(t, "console", "desk"), nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if took := time.Since(start); took > Window+500*time.Millisecond || len(d.Silent) != 0 || len(d.Heard) == 0 {
+		t.Errorf("took %s, heard %d, silent %+v", took, len(d.Heard), d.Silent)
+	}
+}
+
+// Too large even with first lines, descriptions are left out — and the answer says which, without
+// touching the service's own metadata.
+func TestAnAnswerTooLargeIsShortenedUntilItFits(t *testing.T) {
+	long := strings.Repeat("A sentence that is long. ", 20)
+	var endpoints []Endpoint
+	for i := 0; i < 50; i++ {
+		endpoints = append(endpoints, Endpoint{Kind: KindTool, Module: "m", Tool: "t" + strings.Repeat("x", i), Node: "laptop",
+			Description: long, Subject: "mesh.mod.m.tool.t"})
+	}
+	own := map[string]string{"node": "laptop"}
+	info := Info(Service{Name: "node-tools", ID: "laptop", Metadata: own}, endpoints)
+	full, _ := json.Marshal(info)
+	firstLines := 0
+	for range endpoints {
+		firstLines += len(firstLine(long))
+	}
+	limit := int64(len(full) - len(long)*len(endpoints) + firstLines/2) // first lines alone do not fit
+	var said []string
+	got := shorten(func(f string, a ...any) { said = append(said, f) }, info, full, limit)
+	if int64(len(got)) > limit {
+		t.Fatalf("still %d bytes, beyond %d", len(got), limit)
+	}
+	var back micro.Info
+	if err := json.Unmarshal(got, &back); err != nil {
+		t.Fatal(err)
+	}
+	if back.Metadata[Shortened] != "descriptions left out" || back.Metadata["node"] != "laptop" {
+		t.Errorf("metadata: %v", back.Metadata)
+	}
+	if _, has := own[Shortened]; has {
+		t.Error("the service's own metadata was changed")
+	}
+	if len(said) != 2 {
+		t.Errorf("each step is said: %v", said)
+	}
+}

node-tools/internal/bus/bus_test.go

@@ -0,0 +1,62 @@
+package bus
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+)
+
+func TestSubjectsAreTheOnesTheTypeScriptRuntimeUses(t *testing.T) {
+	for key, want := range map[string]string{
+		"status":                      "mesh.mod.self.tool.status",
+		"alpha.one":                   "mesh.mod.alpha.tool.one",
+		"alpha.one@anchor":            "mesh.mod.alpha.tool.one.anchor",
+		"seat:node-shelf.list":        "mesh.seat.node-shelf.tool.list",
+		"seat:node-shelf.list@anchor": "mesh.seat.node-shelf.tool.list.anchor",
+	} {
+		if got, err := ToolSubject(key, "self"); err != nil || got != want {
+			t.Errorf("%s: %s %v, want %s", key, got, err, want)
+		}
+	}
+	if _, err := ToolSubject("seat:nothing", "self"); err == nil {
+		t.Error("a seat with no verb was accepted")
+	}
+	if SeatToolSubject("s", "v", "node", "n") != "mesh.seat.s.tool.v.n" || SeatToolSubject("s", "v", "mesh", "n") != "mesh.seat.s.tool.v" {
+		t.Error("seat subjects")
+	}
+}
+
+func TestAFingerprintIsReadHoweverItIsWritten(t *testing.T) {
+	for _, f := range []string{"sha256:AB:CD:ef", "abcdef", "ABCDEF", "SHA256:abcdef"} {
+		if got := normalizeFingerprint(f); got != "abcdef" {
+			t.Errorf("%s → %s", f, got)
+		}
+	}
+}
+
+func TestWhatWaitingCannotFixIsFinal(t *testing.T) {
+	for err, want := range map[error]string{
+		fmt.Errorf("x509: %w: it presented aa", ErrPin):                   "the bus's certificate does not match the pin",
+		errors.New("nats: Authorization Violation"):                       "the bus refused this account",
+		errors.New("nats: invalid url"):                                   "the bus address is not a usable URL",
+		errors.New("dial tcp 10.0.0.1:4222: connect: connection refused"): "",
+	} {
+		if got := Fatal(err); got != want {
+			t.Errorf("%v → %q, want %q", err, got, want)
+		}
+	}
+}
+
+// An event given up on and delivered again by the controller arrives under `mesh.again.<consumer>.` and
+// the event's own subject without its `mesh.` (novox/hq issue 330): the handler sees the key it saw the
+// first time, for a module's event and a seat's.
+func TestAnEventDeliveredAgainHasItsOwnKey(t *testing.T) {
+	for original, again := range map[string]string{
+		"mesh.mod.gitea.event.pull.merged":       "mesh.again.ace_sonarr.mod.gitea.event.pull.merged",
+		"mesh.seat.node-build-agent.event.built": "mesh.again.ace_sonarr.seat.node-build-agent.event.built",
+	} {
+		if keyOf(again) != keyOf(original) {
+			t.Errorf("%s reads as %q, the event as %q", again, keyOf(again), keyOf(original))
+		}
+	}
+}

node-tools/internal/bus/caller.go

@@ -0,0 +1,212 @@
+package bus
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"regexp"
+	"strings"
+	"sync"
+
+	"github.com/nats-io/nats.go"
+)
+
+// A tool call names its caller (novox/hq issue 365, by ADR 0259 §3's precedent for asks).
+//
+//	mesh.mod.<module>.call.<tool>.<caller>            to whichever instance answers
+//	mesh.mod.<module>.call.<tool>.<node>.<caller>     to the instance on one machine
+//	mesh.seat.<seat>.call.<verb>.<caller>             a mesh seat's verb
+//	mesh.seat.<seat>.call.<verb>.<node>.<caller>      a node seat's verb on one machine
+//
+// The last token is the bus user that published the call, and the controller grants each user the publish of
+// these subjects with its own name there and no other — so the caller is a fact the bus server enforces, and
+// the runtime hands it to the module from the subject a call arrived on, never from the payload.
+//
+// **A kind of its own, `call`, not the `tool` subject with a token appended.** Every grant to call a tool is a
+// wildcard over the `tool` kind — `mesh.mod.<m>.tool.<t>.*` for the instance on any machine, `mesh.mod.*.tool.>`
+// for every tool — and either matches a `tool` subject with any caller appended, so a caller could name
+// another. Under `call` no grant but the caller-named ones reaches the caller token.
+//
+// The `tool` subjects are served beside these for one release, and say Unproven, so callers move without a
+// gap; their retirement is hq issue 464.
+const CallKind = "call"
+
+// A bus user's name carries dots (`<node>.<module>`, `person.<name>`); a subject token cannot. In the token
+// each dot is written `~`, which no part of a bus user's name may hold (the controller refuses any part that
+// is not letters, digits, `_` or `-`), so the token is the user's name and nothing else.
+const userDot = "~"
+
+var userName = regexp.MustCompile(`^[A-Za-z0-9_-]+(\.[A-Za-z0-9_-]+)*$`)
+
+// CallerToken is a bus user's name as the last token of a call it publishes, or "" for a name that is not a
+// bus user's.
+func CallerToken(user string) string {
+	if !userName.MatchString(user) {
+		return ""
+	}
+	return strings.ReplaceAll(user, ".", userDot)
+}
+
+// UserOfToken is the bus user a caller token names, or "" when it names none.
+func UserOfToken(token string) string {
+	user := strings.ReplaceAll(token, userDot, ".")
+	if !userName.MatchString(user) {
+		return ""
+	}
+	return user
+}
+
+// toolShape splits a tool subject — `mesh.mod.<m>.tool.<rest>` or `mesh.seat.<s>.tool.<rest>` — into what
+// comes before the kind and what after; ok is false for any other subject.
+func toolShape(subject string) (head, rest string, ok bool) {
+	parts := strings.SplitN(subject, ".", 5)
+	if len(parts) != 5 || parts[0] != "mesh" || (parts[1] != "mod" && parts[1] != "seat") || parts[3] != "tool" ||
+		parts[2] == "" || parts[4] == "" {
+		return "", "", false
+	}
+	return parts[0] + "." + parts[1] + "." + parts[2], parts[4], true
+}
+
+// CalledSubject is where a call to a tool subject goes naming its caller: the same address under the `call`
+// kind, the caller's token last. "" for a subject that is not a tool's, or a caller that is not a bus user.
+func CalledSubject(subject, user string) string {
+	head, rest, ok := toolShape(subject)
+	token := CallerToken(user)
+	if !ok || token == "" || strings.ContainsAny(rest, "*>") {
+		return ""
+	}
+	return head + "." + CallKind + "." + rest + "." + token
+}
+
+// calledPattern is what a runtime answering a tool subject also subscribes, to hear the calls that name their
+// caller: the same address under the `call` kind, with any caller. "" for a subject that is not a tool's.
+func calledPattern(subject string) string {
+	head, rest, ok := toolShape(subject)
+	if !ok || strings.ContainsAny(rest, "*>") {
+		return ""
+	}
+	return head + "." + CallKind + "." + rest + ".*"
+}
+
+// callerOn is the bus user a call names, from the subject it arrived on: its last token, under a pattern
+// calledPattern made. "" — said by the module as Unproven — for a call on the subject that names no caller.
+func callerOn(pattern, subject string) string {
+	// Only the `call` kind names a caller: a `tool` pattern ending in a wildcard (a node seat's verb on any
+	// machine) is never read as one.
+	parts := strings.SplitN(pattern, ".", 5)
+	if len(parts) != 5 || parts[0] != "mesh" || (parts[1] != "mod" && parts[1] != "seat") || parts[3] != CallKind ||
+		!strings.HasSuffix(pattern, ".*") {
+		return ""
+	}
+	dot := strings.LastIndex(subject, ".")
+	if dot < 0 || subject[:dot] != strings.TrimSuffix(pattern, ".*") {
+		return ""
+	}
+	return UserOfToken(subject[dot+1:])
+}
+
+// CalledHandler answers one call, told who called: the bus user the subject named, or "" when it named none.
+type CalledHandler func(caller string, body json.RawMessage) (any, error)
+
+// callers is what a connection keeps of its caller-named calls: those in flight, by subject, so a refused
+// publish ends its call at once instead of after RequestTimeout.
+type callers struct {
+	mu sync.Mutex
+	// fellBack are the caller-named subjects already said to have reached nobody, so each is said once.
+	fellBack map[string]bool
+	next     uint64
+	pending  map[string]map[uint64]context.CancelCauseFunc
+}
+
+// errCallRefused is the bus refusing a caller-named publish: this user is not granted it yet (the controller's
+// grant not delivered to the bus), so the call is asked again on the subject that names no caller.
+var errCallRefused = errors.New("the bus refused the caller-named subject")
+
+var refusedPublish = regexp.MustCompile(`(?i)Publish to "(\S+)"`)
+
+// publishRefused ends every call in flight on a subject the bus refused this connection the publish of.
+func (c *Conn) publishRefused(err error) bool {
+	if !errors.Is(err, nats.ErrPermissionViolation) {
+		return false
+	}
+	m := refusedPublish.FindStringSubmatch(err.Error())
+	if len(m) < 2 {
+		return false
+	}
+	c.calls.mu.Lock()
+	cancels := c.calls.pending[m[1]]
+	delete(c.calls.pending, m[1])
+	c.calls.mu.Unlock()
+	if len(cancels) > 0 {
+		c.Logf("[mesh-tools] the bus refused this account the caller-named %s; asked again on the subject that "+
+			"names no caller, until the mesh grants it (novox/hq issue 365)", m[1])
+	}
+	for _, cancel := range cancels {
+		cancel(errCallRefused)
+	}
+	return len(cancels) > 0
+}
+
+// askCalled asks once on a caller-named subject. fallBack says the call reached nobody — nothing serves that
+// subject yet, or the bus refused this user its publish — so it may be asked on the subject that names no
+// caller without being done twice.
+func (c *Conn) askCalled(subject string, data []byte) (answered Answered, handingOver, fallBack bool, err error) {
+	ctx, cancel := context.WithCancelCause(context.Background())
+	ctx, stop := context.WithTimeout(ctx, RequestTimeout)
+	defer stop()
+	c.calls.mu.Lock()
+	if c.calls.pending == nil {
+		c.calls.pending = map[string]map[uint64]context.CancelCauseFunc{}
+	}
+	if c.calls.pending[subject] == nil {
+		c.calls.pending[subject] = map[uint64]context.CancelCauseFunc{}
+	}
+	c.calls.next++
+	id := c.calls.next
+	c.calls.pending[subject][id] = cancel
+	c.calls.mu.Unlock()
+	defer func() {
+		c.calls.mu.Lock()
+		if list := c.calls.pending[subject]; list != nil {
+			delete(list, id)
+			if len(list) == 0 {
+				delete(c.calls.pending, subject)
+			}
+		}
+		c.calls.mu.Unlock()
+		cancel(nil)
+	}()
+	msg, err := c.nc.RequestWithContext(ctx, subject, data)
+	if err != nil {
+		switch {
+		case errors.Is(context.Cause(ctx), errCallRefused):
+			return Answered{}, false, true, nil
+		case errors.Is(err, nats.ErrNoResponders):
+			c.saidFallBack(subject)
+			return Answered{}, false, true, nil
+		case errors.Is(err, context.DeadlineExceeded) || errors.Is(err, nats.ErrTimeout):
+			return Answered{}, false, false, errors.New("timeout")
+		}
+		return Answered{}, false, false, err
+	}
+	answered, handingOver, err = c.answerOf(subject, msg.Data)
+	return answered, handingOver, false, err
+}
+
+// saidFallBack says, once per subject, that a caller-named call reached nobody and is asked on the subject that
+// names no caller: a runtime or holder not yet serving it, or a grant that drifted, is seen in the log rather
+// than read later as a quiet "unproven" (novox/hq issue 365; expected for the controller's seat until hq issue
+// 464).
+func (c *Conn) saidFallBack(subject string) {
+	c.calls.mu.Lock()
+	if c.calls.fellBack == nil {
+		c.calls.fellBack = map[string]bool{}
+	}
+	first := !c.calls.fellBack[subject]
+	c.calls.fellBack[subject] = true
+	c.calls.mu.Unlock()
+	if first {
+		c.Logf("[mesh-tools] nothing answers the caller-named %s; asked on the subject that names no caller, where "+
+			"the module is told no caller (said once per subject; novox/hq issue 365)", subject)
+	}
+}

node-tools/internal/bus/caller_bus_test.go

@@ -0,0 +1,218 @@
+package bus_test
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats-server/v2/server"
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// A bus whose users are granted as the controller grants them (mesh-controller internal/broker): each named
+// user publishes the subjects listed for it.
+func grantedBus(t *testing.T, publish map[string][]string) string {
+	t.Helper()
+	var users []*server.User
+	for user, allow := range publish {
+		// And the membership's direct get every connection asks once, answered "no responders" here.
+		allow = append(allow, "$JS.API.DIRECT.GET.>")
+		users = append(users, &server.User{Username: user, Password: "pw", Permissions: &server.Permissions{
+			Publish:   &server.SubjectPermission{Allow: allow},
+			Subscribe: &server.SubjectPermission{Allow: []string{">"}},
+		}})
+	}
+	s, err := server.NewServer(&server.Options{Host: "127.0.0.1", Port: server.RANDOM_PORT, NoLog: true, NoSigs: true,
+		Users: users})
+	if err != nil {
+		t.Fatal(err)
+	}
+	go s.Start()
+	if !s.ReadyForConnections(10 * time.Second) {
+		t.Fatal("the bus did not come up")
+	}
+	t.Cleanup(s.Shutdown)
+	return s.ClientURL()
+}
+
+func dial(t *testing.T, url, module, node, user string) *bus.Conn {
+	t.Helper()
+	c, err := bus.Connect(bus.Credential{URL: url, Module: module, Node: node, User: user, Password: "pw"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.Logf = func(string, ...any) {}
+	t.Cleanup(c.Close)
+	return c
+}
+
+type heard struct {
+	mu      sync.Mutex
+	callers []string
+}
+
+func (h *heard) handler(caller string, _ json.RawMessage) (any, error) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	h.callers = append(h.callers, caller)
+	return map[string]any{"caller": caller}, nil
+}
+
+func (h *heard) all() []string {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return append([]string(nil), h.callers...)
+}
+
+// A caller asks on the caller-named subject first; where nothing serves it yet — a runtime from before issue
+// 365 — the same call is asked once on the subject that names no caller, at once, and done once.
+func TestACallerFallsBackAtOnceWhereNothingServesTheCallerNamedSubject(t *testing.T) {
+	url := mt.URL(t)
+	server := dial(t, url, "ledger", "anchor", "")
+	h := &heard{}
+	// An older runtime: the subject that names no caller, alone.
+	stop, err := server.HandleSubject("mesh.mod.ledger.tool.who", func(body json.RawMessage) (any, error) {
+		return h.handler("", body)
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	server.Flush()
+	asker := dial(t, url, "node-tools", "shanks", "shanks.node-tools")
+	began := time.Now()
+	answered, err := asker.Ask("ledger.who", map[string]any{}, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if took := time.Since(began); took > 2*time.Second {
+		t.Errorf("the fall-back took %s", took)
+	}
+	if got := h.all(); len(got) != 1 || got[0] != "" || !strings.Contains(string(answered.Result), `"caller":""`) {
+		t.Errorf("the call was answered %v, heard %v; want once, on the old subject", string(answered.Result), got)
+	}
+}
+
+// Where the bus does not grant the caller-named subject yet — the controller's grants not yet delivered — the
+// refusal ends the call at once and it is asked on the subject that names no caller: no caller waits out
+// RequestTimeout for a grant that is on its way.
+func TestACallerTheBusRefusesTheCallerNamedSubjectFallsBackAtOnce(t *testing.T) {
+	url := grantedBus(t, map[string][]string{
+		"anchor.node-tools": {"_INBOX.>"},
+		"shanks.node-tools": {"mesh.mod.*.tool.>"},
+	})
+	server := dial(t, url, "node-tools", "anchor", "anchor.node-tools")
+	h := &heard{}
+	stop, err := server.HandleSubjectCalled("mesh.mod.ledger.tool.who", h.handler)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	server.Flush()
+	asker := dial(t, url, "node-tools", "shanks", "shanks.node-tools")
+	var said []string
+	var mu sync.Mutex
+	asker.Logf = func(f string, a ...any) { mu.Lock(); said = append(said, fmt.Sprintf(f, a...)); mu.Unlock() }
+	began := time.Now()
+	if _, err := asker.Ask("ledger.who", map[string]any{}, ""); err != nil {
+		t.Fatal(err)
+	}
+	mu.Lock()
+	if !strings.Contains(strings.Join(said, "\n"), "the bus refused this account the caller-named mesh.mod.ledger.call.who.shanks~node-tools") {
+		t.Errorf("the refusal was not said: %v", said)
+	}
+	mu.Unlock()
+	if took := time.Since(began); took > 3*time.Second {
+		t.Errorf("the refused caller-named call held the caller %s", took)
+	}
+	if got := h.all(); len(got) != 1 || got[0] != "" {
+		t.Errorf("heard %v; want one call, on the subject that names no caller", got)
+	}
+}
+
+// With the controller's grant — the caller-named subjects with its own name last — a caller is heard as itself;
+// and a caller cannot publish on a subject naming another, however it asks.
+func TestAGrantedCallerIsHeardAsItselfAndCannotNameAnother(t *testing.T) {
+	url := grantedBus(t, map[string][]string{
+		"anchor.node-tools": {"_INBOX.>"},
+		"shanks.node-tools": {"mesh.mod.*.call.*.shanks~node-tools", "mesh.mod.*.call.*.*.shanks~node-tools"},
+	})
+	server := dial(t, url, "node-tools", "anchor", "anchor.node-tools")
+	h := &heard{}
+	stop, err := server.HandleSubjectCalled("mesh.mod.ledger.tool.who", h.handler)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	server.Flush()
+	asker := dial(t, url, "node-tools", "shanks", "shanks.node-tools")
+	if _, err := asker.Ask("ledger.who", map[string]any{}, ""); err != nil {
+		t.Fatal(err)
+	}
+	// Naming another on the subject itself: refused by the bus, so nothing is heard.
+	refusals := make(chan error, 4)
+	forger, err := nats.Connect(url, nats.UserInfo("shanks.node-tools", "pw"),
+		nats.ErrorHandler(func(_ *nats.Conn, _ *nats.Subscription, err error) { refusals <- err }))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer forger.Close()
+	if err := forger.Publish("mesh.mod.ledger.call.who.novox~node-tools", []byte(`{}`)); err != nil {
+		t.Fatal(err)
+	}
+	_ = forger.Flush()
+	select {
+	case err := <-refusals:
+		if !errors.Is(err, nats.ErrPermissionViolation) {
+			t.Errorf("the bus said %v, want a permissions violation", err)
+		}
+	case <-time.After(3 * time.Second):
+		t.Error("the bus did not refuse a call naming another caller")
+	}
+	if got := h.all(); len(got) != 1 || got[0] != "shanks.node-tools" {
+		t.Errorf("heard %v; want the asker alone, as itself", got)
+	}
+}
+
+// A fall-back for want of a responder on the caller-named subject is said, once per subject, so a runtime or
+// grant that drifted behind is seen rather than read as a quiet "unproven".
+func TestAFallBackForWantOfAResponderIsSaidOncePerSubject(t *testing.T) {
+	url := mt.URL(t)
+	// A runtime from before issue 365: the subject that names no caller, alone.
+	older, err := nats.Connect(url)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer older.Close()
+	if _, err := older.Subscribe("mesh.mod.ledger.tool.who", func(m *nats.Msg) { _ = m.Respond([]byte(`{"result":{}}`)) }); err != nil {
+		t.Fatal(err)
+	}
+	_ = older.Flush()
+	asker := dial(t, url, "node-tools", "shanks", "shanks.node-tools")
+	var mu sync.Mutex
+	var said []string
+	asker.Logf = func(f string, a ...any) { mu.Lock(); said = append(said, fmt.Sprintf(f, a...)); mu.Unlock() }
+	for i := 0; i < 3; i++ {
+		if _, err := asker.Ask("ledger.who", map[string]any{}, ""); err != nil {
+			t.Fatal(err)
+		}
+	}
+	mu.Lock()
+	defer mu.Unlock()
+	n := 0
+	for _, s := range said {
+		if strings.Contains(s, "nothing answers the caller-named mesh.mod.ledger.call.who.shanks~node-tools") {
+			n++
+		}
+	}
+	if n != 1 {
+		t.Errorf("the fall-back was said %d times, want once: %v", n, said)
+	}
+}

node-tools/internal/bus/caller_test.go

@@ -0,0 +1,72 @@
+package bus
+
+import "testing"
+
+// A call names its caller under the `call` kind, the caller's bus user its last token (novox/hq issue 365).
+func TestACallerNamedSubjectIsTheToolsAddressUnderCallWithTheCallerLast(t *testing.T) {
+	for subject, want := range map[string]string{
+		"mesh.mod.ledger.tool.who":             "mesh.mod.ledger.call.who.shanks~node-tools",
+		"mesh.mod.ledger.tool.who.anchor":      "mesh.mod.ledger.call.who.anchor.shanks~node-tools",
+		"mesh.seat.issue-tracker.tool.open":    "mesh.seat.issue-tracker.call.open.shanks~node-tools",
+		"mesh.seat.node-desk.tool.who.anchor":  "mesh.seat.node-desk.call.who.anchor.shanks~node-tools",
+		"mesh.mod.ledger.event.opened":         "",
+		"mesh.seat.intake.accept.ask.x":        "",
+		"mesh.mod.ledger.tool.>":               "",
+		"mesh.mod.*.tool.who":                  "mesh.mod.*.call.who.shanks~node-tools",
+		"mesh.node.anchor.ask.report":          "",
+		"mesh.seat.operator-channel.proof.x.y": "",
+	} {
+		if subject == "mesh.mod.*.tool.who" {
+			continue // a wildcard is never asked on
+		}
+		if got := CalledSubject(subject, "shanks.node-tools"); got != want {
+			t.Errorf("%s → %q, want %q", subject, got, want)
+		}
+	}
+	for _, user := range []string{"", "a b", "x.*", "x.>", "a~b", "a..b"} {
+		if got := CalledSubject("mesh.mod.ledger.tool.who", user); got != "" {
+			t.Errorf("a caller %q that is not a bus user was named: %s", user, got)
+		}
+	}
+}
+
+// The caller is read back from the subject a call arrived on, and only under the pattern that names one.
+func TestTheCallerIsTheLastTokenOfTheSubjectTheCallArrivedOn(t *testing.T) {
+	pattern := calledPattern("mesh.mod.ledger.tool.who.anchor")
+	if pattern != "mesh.mod.ledger.call.who.anchor.*" {
+		t.Fatalf("pattern %q", pattern)
+	}
+	for subject, want := range map[string]string{
+		"mesh.mod.ledger.call.who.anchor.shanks~node-tools": "shanks.node-tools",
+		"mesh.mod.ledger.call.who.anchor.controller":        "controller",
+		"mesh.mod.ledger.call.who.anchor.person~jochen":     "person.jochen",
+		"mesh.mod.ledger.call.who.anchor.a~~b":              "",
+		"mesh.mod.ledger.call.what.anchor.controller":       "",
+	} {
+		if got := callerOn(pattern, subject); got != want {
+			t.Errorf("%s → %q, want %q", subject, got, want)
+		}
+	}
+	if got := callerOn("mesh.mod.ledger.tool.who.anchor", "mesh.mod.ledger.tool.who.anchor"); got != "" {
+		t.Errorf("a call on the subject that names no caller was handed %q", got)
+	}
+	for _, user := range []string{"controller", "shanks.node-tools", "person.jochen", "node.ace"} {
+		if back := UserOfToken(CallerToken(user)); back != user {
+			t.Errorf("%s → %s → %s", user, CallerToken(user), back)
+		}
+	}
+}
+
+// Only a pattern of the `call` kind names a caller: a `tool` subscription with a wildcard last — a node seat's
+// verb on any machine, say — never yields one, whatever token a call arrived with.
+func TestAToolPatternNeverYieldsACaller(t *testing.T) {
+	for pattern, subject := range map[string]string{
+		"mesh.mod.ledger.tool.who.*":     "mesh.mod.ledger.tool.who.controller",
+		"mesh.seat.node-desk.tool.who.*": "mesh.seat.node-desk.tool.who.shanks~node-tools",
+		"mesh.mod.ledger.event.*":        "mesh.mod.ledger.event.controller",
+	} {
+		if got := callerOn(pattern, subject); got != "" {
+			t.Errorf("%s on %s yielded caller %q", pattern, subject, got)
+		}
+	}
+}

node-tools/internal/bus/consume_test.go

@@ -0,0 +1,62 @@
+package bus_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// novox/hq issue 387: an event a bundle handles for longer than the consumer's ack wait is kept alive while
+// it is handled, and the events behind it wait on the bus rather than in the client, so a slow handler and a
+// burst are each handed over once — never offered again with nothing failed, never toward max-deliver.
+func TestASlowHandlerAndABurstAreEachHandedOverOnce(t *testing.T) {
+	mesh := mt.New(t)
+	restore := bus.EventHeartbeat
+	bus.EventHeartbeat = 300 * time.Millisecond
+	t.Cleanup(func() { bus.EventHeartbeat = restore })
+	mesh.Consumer(t, "anchor", "slow", []string{"mesh.mod.alpha.event.>"}, time.Second)
+	c, err := bus.Connect(bus.Credential{URL: mt.URL(t), Module: "node-tools", Node: "anchor"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.Logf = func(string, ...any) {}
+	t.Cleanup(c.Close)
+
+	var mu sync.Mutex
+	handled := map[int]int{}
+	stop, err := c.ConsumeAs("slow", func(env bus.Envelope) error {
+		var body struct{ N int }
+		_ = json.Unmarshal(env.Body, &body)
+		time.Sleep(1500 * time.Millisecond) // longer than the ack wait
+		mu.Lock()
+		handled[body.N]++
+		mu.Unlock()
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	for n := 1; n <= 3; n++ {
+		mesh.Emit(t, "mesh.mod.alpha.event.happened", map[string]any{"n": n})
+	}
+	mt.Until(t, func() error {
+		ack, notYet := mesh.Pending(t, "anchor", "slow")
+		if ack != 0 || notYet != 0 {
+			return fmt.Errorf("still pending: %d unacknowledged, %d undelivered", ack, notYet)
+		}
+		return nil
+	})
+	mu.Lock()
+	defer mu.Unlock()
+	for n := 1; n <= 3; n++ {
+		if handled[n] != 1 {
+			t.Errorf("event %d was handed over %d times: %v", n, handled[n], handled)
+		}
+	}
+}

node-tools/internal/bus/handover_test.go

@@ -0,0 +1,73 @@
+package bus_test
+
+import (
+	"encoding/json"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// **A call the controller refused because it is handing over is asked once more** (novox/hq issue 289):
+// the controller being replaced did nothing and marked its refusal, and the one after it answers. A
+// refusal not so marked is final, and a second handover refusal is said, not asked a third time.
+func TestAHandoverRefusalIsAskedOnceMore(t *testing.T) {
+	was := bus.HandoverPause
+	bus.HandoverPause = 10 * time.Millisecond
+	t.Cleanup(func() { bus.HandoverPause = was })
+
+	url := meshtest.URL(t)
+	seat, err := nats.Connect(url)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer seat.Close()
+	c, err := bus.Connect(bus.Credential{URL: url, Module: "console", Node: "anchor"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	serve := func(t *testing.T, verb string, answers ...map[string]any) *atomic.Int32 {
+		t.Helper()
+		var asked atomic.Int32
+		sub, err := seat.Subscribe(bus.SeatToolSubject("mesh-controller", verb, "", ""), func(m *nats.Msg) {
+			n := int(asked.Add(1)) - 1
+			if n >= len(answers) {
+				n = len(answers) - 1
+			}
+			body, _ := json.Marshal(answers[n])
+			_ = m.Respond(body)
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { _ = sub.Unsubscribe() })
+		_ = seat.Flush()
+		return &asked
+	}
+	handingOver := map[string]any{"error": "the controller is handing over to the next one; nothing was done, ask again",
+		"retry": bus.RetryHandingOver}
+
+	asked := serve(t, "rotate", handingOver, map[string]any{"result": "rotated"})
+	got, err := c.Ask("seat:mesh-controller.rotate", map[string]any{}, "")
+	if err != nil || string(got.Result) != `"rotated"` || asked.Load() != 2 {
+		t.Fatalf("after a handover refusal: %s %v, asked %d times", got.Result, err, asked.Load())
+	}
+
+	asked = serve(t, "push", map[string]any{"error": "refused for its own reason"})
+	if _, err := c.Ask("seat:mesh-controller.push", map[string]any{}, ""); err == nil || asked.Load() != 1 {
+		t.Fatalf("an unmarked refusal was asked again: %v, asked %d times", err, asked.Load())
+	}
+
+	asked = serve(t, "status", handingOver)
+	_, err = c.Ask("seat:mesh-controller.status", map[string]any{}, "")
+	if err == nil || asked.Load() != 2 || !strings.Contains(err.Error(), "both times refused as a handover") {
+		t.Fatalf("two handover refusals: %v, asked %d times", err, asked.Load())
+	}
+}

node-tools/internal/bus/log.go

@@ -0,0 +1,367 @@
+package bus
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// A module's log on the bus (novox/hq ADR 0297): a stream of operations, one subject per key, that the
+// controller creates from what the module declared under `logs` and issues to the module's own instances
+// in its membership. It mirrors a bucket (ADR 0201) in how it is reached: what a module may reach is
+// decided here, from its membership, and refused with the reason before anything is sent.
+//
+// **The runtime uses no consumer of a log.** The bus grants it, per issued log, only the publish of an
+// entry, the stream's info and the direct get: an append is a publish, a read is a batch direct get
+// (NATS 2.11), the last entry of a key is a direct get by its subject.
+
+// LogIssued is one log an assignment may reach (ADR 0297): its owner's alone, so there are no reads.
+type LogIssued struct {
+	Name    string `json:"name"`
+	Stream  string `json:"stream"`
+	Subject string `json:"subject"`
+	Writes  bool   `json:"writes,omitempty"`
+}
+
+// LogEntry is one operation in a log: its sequence is its identity.
+type LogEntry struct {
+	Sequence uint64          `json:"sequence"`
+	Key      string          `json:"key"`
+	Value    json.RawMessage `json:"value"`
+	At       time.Time       `json:"at"`
+}
+
+// LogPage is one page of a read: Next is the sequence to continue from, 0 when nothing follows; Last
+// is the stream's last sequence.
+type LogPage struct {
+	Entries []LogEntry `json:"entries"`
+	Next    uint64     `json:"next"`
+	Last    uint64     `json:"last"`
+}
+
+// LogInfo is how full a log is.
+type LogInfo struct {
+	Entries  uint64 `json:"entries"`
+	Bytes    uint64 `json:"bytes"`
+	MaxBytes uint64 `json:"max_bytes"`
+	First    uint64 `json:"first"`
+	Last     uint64 `json:"last"`
+}
+
+const (
+	// LogValueMax is the most one entry's value may hold (ADR 0297 §3); the stream's MaxMsgSize is 4 KiB
+	// more, for the headers an append carries.
+	LogValueMax = 256 * 1024
+	// LogKeyMax is the longest key.
+	LogKeyMax = 255
+	// LogReadDefault and LogReadMax are a page's entries when none is asked, and at most.
+	LogReadDefault = 100
+	LogReadMax     = 1000
+	// LogPageBytes bounds the bytes of one page.
+	LogPageBytes = 4 * 1024 * 1024
+)
+
+// logToken is one name of a key: letters, digits, `_` and `-`.
+var logToken = regexp.MustCompile(`^[A-Za-z0-9_-]+$`)
+
+func checkLogKey(key string) error {
+	if key == "" || len(key) > LogKeyMax {
+		return fmt.Errorf("%q is not a log key: one or more names of letters, digits, _ and -, joined by "+
+			"dots, at most %d bytes (novox/hq ADR 0297)", key, LogKeyMax)
+	}
+	for _, t := range strings.Split(key, ".") {
+		if !logToken.MatchString(t) {
+			return fmt.Errorf("%q is not a log key: one or more names of letters, digits, _ and -, joined by "+
+				"dots, at most %d bytes (novox/hq ADR 0297)", key, LogKeyMax)
+		}
+	}
+	return nil
+}
+
+// logFilter is a read's key pattern as a subject filter under the log's subject: `*` for one name, `>`
+// for the rest; empty is every key.
+func logFilter(l LogIssued, pattern string) (string, error) {
+	if pattern == "" {
+		return l.Subject + ".>", nil
+	}
+	parts := strings.Split(pattern, ".")
+	for i, p := range parts {
+		switch {
+		case p == ">" && i == len(parts)-1, p == "*", logToken.MatchString(p):
+		default:
+			return "", fmt.Errorf("%q is not a key pattern: names, `*` for one and `>` for the rest, last "+
+				"(novox/hq ADR 0297)", pattern)
+		}
+	}
+	if len(pattern) > LogKeyMax {
+		return "", fmt.Errorf("%q is longer than a key can be (%d bytes)", pattern, LogKeyMax)
+	}
+	return l.Subject + "." + pattern, nil
+}
+
+// issuedLog is the log a module may reach by a name, or the reason it may not.
+func (c *Conn) issuedLog(module, name string) (LogIssued, error) {
+	m := c.Membership(module)
+	if m == nil {
+		return LogIssued{}, fmt.Errorf("%s has no membership issued on %s yet, so no log of it is reachable "+
+			"until the mesh issues one (novox/hq ADR 0297)", module, c.node)
+	}
+	var names []string
+	for _, l := range m.Logs {
+		if l.Name == name {
+			return l, nil
+		}
+		names = append(names, l.Name)
+	}
+	sort.Strings(names)
+	issued := "none"
+	if len(names) > 0 {
+		issued = strings.Join(names, ", ")
+	}
+	return LogIssued{}, fmt.Errorf("%s keeps no log called %q: a module declares the logs it keeps under `logs`, "+
+		"and a log is its owner's alone; it was issued: %s (novox/hq ADR 0297)", module, name, issued)
+}
+
+// notOnTheBus says a log is issued and its stream is not there yet.
+func notOnTheBus(l LogIssued) error {
+	return fmt.Errorf("the log %q is issued and its stream %s is not on the bus yet: the controller creates "+
+		"it from the catalogue on its next raise (novox/hq ADR 0297)", l.Name, l.Stream)
+}
+
+// LogAppend writes one entry for a key, as the module, and answers its sequence. With expect, it is
+// written only when the key's last entry is still at that sequence (0: the key has none); otherwise it
+// is refused as a lost compare-and-set, the same error a lost state update answers (ADR 0259).
+func (c *Conn) LogAppend(module, name, key string, value json.RawMessage, expect *uint64) (uint64, error) {
+	l, err := c.issuedLog(module, name)
+	if err != nil {
+		return 0, err
+	}
+	if !l.Writes {
+		return 0, fmt.Errorf("%s was issued the log %s without writing it (novox/hq ADR 0297)", module, name)
+	}
+	if err := checkLogKey(key); err != nil {
+		return 0, err
+	}
+	if len(value) == 0 || !json.Valid(value) {
+		return 0, fmt.Errorf("a log entry's value is JSON (novox/hq ADR 0297)")
+	}
+	if len(value) > LogValueMax {
+		return 0, fmt.Errorf("a log entry's value is at most %d bytes (256 KiB), and this one is %d (novox/hq ADR 0297)",
+			LogValueMax, len(value))
+	}
+	if field := credentialField(value); field != "" {
+		return 0, fmt.Errorf("%s's %s.%s carries a field %q, which names a credential: no secret is kept in a log, "+
+			"which keeps it for good. Name the secret and fetch it on request/reply (novox/hq ADR 0201 §13, ADR 0297)",
+			module, name, key, field)
+	}
+	msg := nats.NewMsg(l.Subject + "." + key)
+	msg.Data = value
+	if expect != nil {
+		msg.Header.Set(jetstream.ExpectedLastSubjSeqHeader, strconv.FormatUint(*expect, 10))
+	}
+	reply, err := c.nc.RequestMsg(msg, StateTimeout)
+	if errors.Is(err, nats.ErrNoResponders) {
+		return 0, notOnTheBus(l)
+	}
+	if err != nil {
+		return 0, err
+	}
+	var ack struct {
+		Seq   uint64 `json:"seq"`
+		Error *struct {
+			Code        int    `json:"code"`
+			ErrCode     uint16 `json:"err_code"`
+			Description string `json:"description"`
+		} `json:"error"`
+	}
+	if err := json.Unmarshal(reply.Data, &ack); err != nil {
+		return 0, fmt.Errorf("the bus answered the append to %s with what is not an acknowledgement: %q", name, reply.Data)
+	}
+	if ack.Error != nil {
+		// The key's last entry is no longer the one expected: a lost compare-and-set, answered as a lost
+		// state update is (10164 is the same refusal from a replicated stream).
+		if code := jetstream.ErrorCode(ack.Error.ErrCode); code == jetstream.JSErrCodeStreamWrongLastSequence ||
+			code == jetstream.JSErrCodeStreamWrongLastSequenceConstant {
+			return 0, changed{name + "." + key}
+		}
+		return 0, fmt.Errorf("the bus refused the append to %s.%s: %s (%d)", name, key, ack.Error.Description, ack.Error.ErrCode)
+	}
+	if ack.Seq == 0 {
+		return 0, fmt.Errorf("the bus answered the append to %s.%s with no sequence", name, key)
+	}
+	return ack.Seq, nil
+}
+
+// LogRead is the entries from a sequence on, of the keys matching a pattern, at most limit of them and
+// about 4 MiB, by one batch direct get.
+func (c *Conn) LogRead(module, name string, from uint64, keys string, limit int) (*LogPage, error) {
+	l, err := c.issuedLog(module, name)
+	if err != nil {
+		return nil, err
+	}
+	switch {
+	case limit == 0:
+		limit = LogReadDefault
+	case limit < 0 || limit > LogReadMax:
+		return nil, fmt.Errorf("a read's limit is 1 to %d entries, %d when none is given, not %d (novox/hq ADR 0297)",
+			LogReadMax, LogReadDefault, limit)
+	}
+	filter, err := logFilter(l, keys)
+	if err != nil {
+		return nil, err
+	}
+	if from == 0 {
+		from = 1
+	}
+	req, _ := json.Marshal(map[string]any{"seq": from, "next_by_subj": filter, "batch": limit, "max_bytes": LogPageBytes})
+	inbox := c.nc.NewInbox()
+	sub, err := c.nc.SubscribeSync(inbox)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = sub.Unsubscribe() }()
+	if err := c.nc.PublishRequest("$JS.API.DIRECT.GET."+l.Stream, inbox, req); err != nil {
+		return nil, err
+	}
+	page := &LogPage{Entries: []LogEntry{}}
+	deadline := time.Now().Add(StateTimeout)
+	for done := false; !done; {
+		msg, err := sub.NextMsg(time.Until(deadline))
+		if err != nil {
+			if errors.Is(err, nats.ErrNoResponders) {
+				return nil, notOnTheBus(l)
+			}
+			if errors.Is(err, nats.ErrTimeout) {
+				return nil, fmt.Errorf("the read of %s did not end in %s", name, StateTimeout)
+			}
+			return nil, err
+		}
+		switch status := msg.Header.Get("Status"); status {
+		case "":
+			e, err := logEntryOf(l, msg)
+			if err != nil {
+				return nil, err
+			}
+			page.Entries = append(page.Entries, *e)
+		case "204": // the end of the batch: what is still pending after the last entry sent
+			pending, _ := strconv.ParseUint(msg.Header.Get("Nats-Num-Pending"), 10, 64)
+			if pending > 0 && len(page.Entries) > 0 {
+				page.Next = page.Entries[len(page.Entries)-1].Sequence + 1
+			}
+			done = true
+		case "404": // nothing from that sequence on
+			done = true
+		case "503":
+			return nil, notOnTheBus(l)
+		default:
+			return nil, fmt.Errorf("the read of %s was refused by the bus: %s %s", name, status, msg.Header.Get("Description"))
+		}
+	}
+	info, err := c.logInfo(l)
+	if err != nil {
+		return nil, err
+	}
+	page.Last = info.Last
+	return page, nil
+}
+
+// LogLast is a key's last entry, or nil when it has none.
+func (c *Conn) LogLast(module, name, key string) (*LogEntry, error) {
+	l, err := c.issuedLog(module, name)
+	if err != nil {
+		return nil, err
+	}
+	if err := checkLogKey(key); err != nil {
+		return nil, err
+	}
+	reply, err := c.nc.Request("$JS.API.DIRECT.GET."+l.Stream+"."+l.Subject+"."+key, nil, StateTimeout)
+	if errors.Is(err, nats.ErrNoResponders) {
+		return nil, notOnTheBus(l)
+	}
+	if err != nil {
+		return nil, err
+	}
+	switch status := reply.Header.Get("Status"); status {
+	case "":
+		return logEntryOf(l, reply)
+	case "404":
+		return nil, nil
+	default:
+		return nil, fmt.Errorf("the last entry of %s.%s could not be read: %s %s", name, key, status, reply.Header.Get("Description"))
+	}
+}
+
+// LogInfo is a log's entries, bytes, cap and first and last sequences.
+func (c *Conn) LogInfo(module, name string) (*LogInfo, error) {
+	l, err := c.issuedLog(module, name)
+	if err != nil {
+		return nil, err
+	}
+	return c.logInfo(l)
+}
+
+func (c *Conn) logInfo(l LogIssued) (*LogInfo, error) {
+	reply, err := c.nc.Request("$JS.API.STREAM.INFO."+l.Stream, nil, StateTimeout)
+	if errors.Is(err, nats.ErrNoResponders) {
+		return nil, notOnTheBus(l)
+	}
+	if err != nil {
+		return nil, err
+	}
+	var info struct {
+		Config struct {
+			MaxBytes int64 `json:"max_bytes"`
+		} `json:"config"`
+		State struct {
+			Msgs     uint64 `json:"messages"`
+			Bytes    uint64 `json:"bytes"`
+			FirstSeq uint64 `json:"first_seq"`
+			LastSeq  uint64 `json:"last_seq"`
+		} `json:"state"`
+		Error *struct {
+			ErrCode     uint16 `json:"err_code"`
+			Description string `json:"description"`
+		} `json:"error"`
+	}
+	if err := json.Unmarshal(reply.Data, &info); err != nil {
+		return nil, fmt.Errorf("the bus answered the info of %s with what is not one: %q", l.Name, reply.Data)
+	}
+	if info.Error != nil {
+		if info.Error.ErrCode == uint16(jetstream.JSErrCodeStreamNotFound) {
+			return nil, notOnTheBus(l)
+		}
+		return nil, fmt.Errorf("the info of the log %s was refused: %s (%d)", l.Name, info.Error.Description, info.Error.ErrCode)
+	}
+	var maxBytes uint64
+	if info.Config.MaxBytes > 0 {
+		maxBytes = uint64(info.Config.MaxBytes)
+	}
+	return &LogInfo{Entries: info.State.Msgs, Bytes: info.State.Bytes, MaxBytes: maxBytes,
+		First: info.State.FirstSeq, Last: info.State.LastSeq}, nil
+}
+
+// logEntryOf is an entry a direct get answered: its key is its subject under the log's.
+func logEntryOf(l LogIssued, msg *nats.Msg) (*LogEntry, error) {
+	subject := msg.Header.Get("Nats-Subject")
+	key, ok := strings.CutPrefix(subject, l.Subject+".")
+	if !ok {
+		return nil, fmt.Errorf("the bus answered an entry of %s on %q, which is not under %s", l.Name, subject, l.Subject)
+	}
+	seq, err := strconv.ParseUint(msg.Header.Get("Nats-Sequence"), 10, 64)
+	if err != nil {
+		return nil, fmt.Errorf("the bus answered an entry of %s with no sequence", l.Name)
+	}
+	at, err := time.Parse(time.RFC3339Nano, msg.Header.Get("Nats-Time-Stamp"))
+	if err != nil {
+		return nil, fmt.Errorf("the bus answered entry %d of %s with no time: %v", seq, l.Name, err)
+	}
+	return &LogEntry{Sequence: seq, Key: key, Value: valueOf(msg.Data), At: at.UTC()}, nil
+}

node-tools/internal/bus/pages.go

@@ -0,0 +1,123 @@
+package bus
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/wire"
+)
+
+// An answer larger than the bus carries in one message (novox/hq issue 314).
+//
+// The bus carries one message of at most its max_payload, and the client library refuses a larger one
+// before it leaves the process that sent it. Until this, a holder whose answer was too large wrote one
+// line to its own log and its caller waited out RequestTimeout and read "did not answer" — the
+// controller's `conditions` and `status` for hours on 2026-10-08, and the operator's channel with them.
+//
+// The controller pages such an answer (mesh-controller internal/link, pages.go): it answers an error
+// carrying `paged` — the call it holds the answer under, its size and its parts — and a caller asks the
+// same subject again once per part with PageHeader, each part answered raw with PartHeader. Asking the
+// same subject means no grant beyond the one the caller already had. A module's answer too large is
+// refused here, loudly, in a message that fits: its instances may be several, and a part asked again
+// could reach another.
+
+const (
+	// PageHeader asks for one part of a paged answer: `<call> <part>`, from zero.
+	PageHeader = "Mesh-Page"
+	// PartHeader is on a part: `<part>/<parts>`.
+	PartHeader = "Mesh-Part"
+	// partTries is how often one part is asked: during a handover a part can reach the controller that
+	// did not hold it.
+	partTries = 3
+)
+
+// PartTimeout bounds the asking of one part.
+var PartTimeout = 10 * time.Second
+
+// paged is what a too-large answer says instead of itself.
+type paged struct {
+	Call  string `json:"call"`
+	Bytes int    `json:"bytes"`
+	Parts int    `json:"parts"`
+}
+
+func pagedIn(data []byte) (paged, bool) {
+	if !bytes.Contains(data, []byte(`"paged"`)) {
+		return paged{}, false
+	}
+	var r struct {
+		Paged *paged `json:"paged"`
+	}
+	if json.Unmarshal(data, &r) != nil || r.Paged == nil || r.Paged.Call == "" || r.Paged.Parts < 1 {
+		return paged{}, false
+	}
+	return *r.Paged, true
+}
+
+// whole is a reply's whole answer: the reply itself, or every part of a paged one, joined. A part that
+// cannot be had is an error naming it, never a shorter answer.
+func (c *Conn) whole(subject string, data []byte) ([]byte, error) {
+	p, ok := pagedIn(data)
+	if !ok {
+		return data, nil
+	}
+	out := make([]byte, 0, p.Bytes)
+	for n := 0; n < p.Parts; n++ {
+		var part []byte
+		var err error
+		for try := 0; try < partTries; try++ {
+			if part, err = c.askPart(subject, p, n); err == nil {
+				break
+			}
+		}
+		if err != nil {
+			return nil, fmt.Errorf("the answer was %d bytes, more than the bus carries in one message, paged as %s "+
+				"in %d parts, and part %d could not be had: %w", p.Bytes, p.Call, p.Parts, n, err)
+		}
+		out = append(out, part...)
+	}
+	if len(out) != p.Bytes {
+		return nil, fmt.Errorf("the answer paged as %s was %d bytes, and its parts joined are %d", p.Call, p.Bytes, len(out))
+	}
+	return out, nil
+}
+
+func (c *Conn) askPart(subject string, p paged, n int) ([]byte, error) {
+	ask := nats.NewMsg(subject)
+	ask.Header.Set(PageHeader, fmt.Sprintf("%s %d", p.Call, n))
+	ask.Data = []byte(`{}`)
+	reply, err := c.nc.RequestMsg(ask, PartTimeout)
+	if err != nil {
+		return nil, err
+	}
+	if got := reply.Header.Get(PartHeader); got != fmt.Sprintf("%d/%d", n, p.Parts) {
+		var r struct {
+			Error string `json:"error"`
+		}
+		if json.Unmarshal(reply.Data, &r) == nil && r.Error != "" {
+			return nil, errors.New(r.Error)
+		}
+		return nil, fmt.Errorf("asked part %d/%d, answered %q", n, p.Parts, got)
+	}
+	return reply.Data, nil
+}
+
+// fits is an answer the bus can carry: the answer itself, or — when it is larger than one message —
+// an error that says so, which is.
+func (c *Conn) fits(subject string, body []byte) []byte {
+	limit := c.nc.MaxPayload()
+	if limit <= 0 || int64(len(body)) <= limit {
+		return body
+	}
+	c.Logf("[mesh-tools] the answer on %s is %d bytes, more than the bus carries in one message (%d): its caller "+
+		"is told so instead", subject, len(body), limit)
+	said, _ := wire.Marshal(reply{Node: c.node, Error: fmt.Sprintf("the answer is %d bytes, more than the bus "+
+		"carries in one message (%d), so it was not sent: ask for less — a narrower question, a shorter window, "+
+		"fewer lines", len(body), limit)})
+	return said
+}

node-tools/internal/bus/pages_test.go

@@ -0,0 +1,80 @@
+package bus_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// novox/hq issue 314: an answer larger than the bus carries in one message arrives whole when the
+// controller pages it, and a module's is said to be too large — neither is a 30-second silence.
+func TestAnAnswerLargerThanOneMessage(t *testing.T) {
+	url := meshtest.URL(t)
+	seat, err := nats.Connect(url)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer seat.Close()
+	c, err := bus.Connect(bus.Credential{URL: url, Module: "console", Node: "anchor"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	limit := int(seat.MaxPayload())
+
+	// The controller as it pages (mesh-controller internal/link, pages.go): the first answer an error
+	// with `paged`, each part asked again on the same subject with the page header.
+	large := strings.Repeat("a condition held past its bound; ", 3*limit/32)
+	whole, _ := json.Marshal(map[string]any{"result": large})
+	partSize := limit - 1024
+	parts := (len(whole) + partSize - 1) / partSize
+	sub, err := seat.Subscribe(bus.SeatToolSubject("mesh-controller", "conditions", "", ""), func(m *nats.Msg) {
+		if page := m.Header.Get(bus.PageHeader); page != "" {
+			var id string
+			var n int
+			fmt.Sscanf(page, "%s %d", &id, &n)
+			end := min((n+1)*partSize, len(whole))
+			part := nats.NewMsg(m.Reply)
+			part.Header.Set(bus.PartHeader, fmt.Sprintf("%d/%d", n, parts))
+			part.Data = whole[n*partSize : end]
+			_ = m.RespondMsg(part)
+			return
+		}
+		body, _ := json.Marshal(map[string]any{"error": "too large for one message",
+			"paged": map[string]any{"call": "call-1-1", "bytes": len(whole), "parts": parts}})
+		_ = m.Respond(body)
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer sub.Unsubscribe()
+	_ = seat.Flush()
+
+	got, err := c.Ask("seat:mesh-controller.conditions", map[string]any{}, "")
+	var said string
+	if err != nil || json.Unmarshal(got.Result, &said) != nil || said != large {
+		t.Fatalf("an answer of %d bytes in %d parts arrived as %d bytes: %v", len(whole), parts, len(got.Result), err)
+	}
+
+	// A module's answer too large is refused here in words, at once.
+	stop, err := c.HandleSubject("mesh.mod.journal.tool.lines", func(json.RawMessage) (any, error) { return large, nil })
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	asked := time.Now()
+	_, err = c.Ask("journal.lines", map[string]any{}, "mesh.mod.journal.tool.lines")
+	if err == nil || !strings.Contains(err.Error(), "more than the bus carries") {
+		t.Fatalf("a module's answer too large for one message read as %v", err)
+	}
+	if took := time.Since(asked); took > 5*time.Second {
+		t.Fatalf("it took %s to say", took)
+	}
+}

node-tools/internal/bus/refused_test.go

@@ -0,0 +1,86 @@
+package bus
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+)
+
+// novox/hq issue 222: a subscription the bus refused is asked for again. A push sends the machine
+// that needs a grant and the bus's machine together; the runtime may subscribe the moment before the
+// bus reloads, and a refusal must not leave the module unreachable until some later membership.
+func TestARefusedSubscriptionIsAskedForAgain(t *testing.T) {
+	url := os.Getenv("MESH_TEST_NATS")
+	if url == "" {
+		t.Skip("MESH_TEST_NATS unset")
+	}
+	c, err := Connect(Credential{URL: url, Module: "alpha", Node: "anchor"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	var mu sync.Mutex
+	var said []string
+	c.Logf = func(f string, a ...any) { mu.Lock(); said = append(said, fmt.Sprintf(f, a...)); mu.Unlock() }
+	c.RetryAfter = []time.Duration{50 * time.Millisecond, 50 * time.Millisecond}
+
+	subject := "mesh.mod.alpha.tool.ping.anchor"
+	stop, err := c.answerOn(subject, "", func(json.RawMessage) (any, error) { return "pong", nil })
+	if err != nil {
+		t.Fatal(err)
+	}
+	first := c.answering[answeringKey(subject, "")].sub
+
+	// What the bus says when the grant is not there yet.
+	c.refused(fmt.Errorf("%w: Permissions Violation for Subscription to %q", nats.ErrPermissionViolation, subject))
+	deadline := time.Now().Add(2 * time.Second)
+	for {
+		c.mu.Lock()
+		again := c.answering[answeringKey(subject, "")].sub
+		c.mu.Unlock()
+		if again != first {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("the refused subscription was not asked for again")
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	asker, err := nats.Connect(url)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer asker.Close()
+	reply, err := asker.Request(subject, []byte("{}"), 2*time.Second)
+	if err != nil {
+		t.Fatalf("the subject asked for again does not answer: %v", err)
+	}
+	if !strings.Contains(string(reply.Data), "pong") {
+		t.Fatalf("the subject asked for again answered %s", reply.Data)
+	}
+
+	// Past its attempts it is given up, and said.
+	for i := 0; i < 3; i++ {
+		c.refused(fmt.Errorf("%w: Permissions Violation for Subscription to %q", nats.ErrPermissionViolation, subject))
+		time.Sleep(80 * time.Millisecond)
+	}
+	mu.Lock()
+	gaveUp := strings.Contains(strings.Join(said, "\n"), "still refuses "+subject)
+	mu.Unlock()
+	if !gaveUp {
+		t.Errorf("never gave up on a subject that stays refused:\n%s", strings.Join(said, "\n"))
+	}
+
+	// A subject the runtime stopped answering is not asked for again.
+	stop()
+	c.refused(fmt.Errorf("%w: Permissions Violation for Subscription to %q", nats.ErrPermissionViolation, subject))
+	if _, still := c.answering[answeringKey(subject, "")]; still {
+		t.Error("a stopped subject is still tracked")
+	}
+}

node-tools/internal/bus/seat.go

@@ -0,0 +1,439 @@
+package bus
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// A bundle's traffic on seats that name their caller or their kind (novox/hq ADR 0259 §3): submitting an
+// accept and saying an event under its own name or kind, taking a held seat's work from its worker, asking a
+// proof and answering one, and reading a record kept for it.
+//
+// **The runtime keeps each module to its own name and kind.** One account per machine carries every module
+// on it, so the bus enforces only the union; what one module may reach is its membership's `seat-traffic`,
+// and anything else is refused here, with the reason, before it is sent. A bundle reaches this only through
+// its own standard input and output: no tool call does.
+
+// SeatTraffic is what a membership lists of a module's seat traffic (the controller's broker.SeatTraffic).
+type SeatTraffic struct {
+	Publish   []string     `json:"publish,omitempty"`
+	Subscribe []string     `json:"subscribe,omitempty"`
+	Answers   []string     `json:"answers,omitempty"`
+	Workers   []SeatWorker `json:"workers,omitempty"`
+	Records   []string     `json:"records,omitempty"`
+	// Kinds are the holders of every kinded bench the module uses or watches, with what each promises: the
+	// controller's record of their claims (novox/hq ADR 0259 §5).
+	Kinds []KindHeld `json:"kinds,omitempty"`
+}
+
+// KindHeld is one kind of a kinded bench and who holds it.
+type KindHeld struct {
+	Seat         string   `json:"seat"`
+	Kind         string   `json:"kind"`
+	Module       string   `json:"module"`
+	Node         string   `json:"node"`
+	Capabilities []string `json:"capabilities,omitempty"`
+}
+
+// SeatKinds is the kinds the module's membership names, as the controller issued them.
+func (c *Conn) SeatKinds(module string) ([]KindHeld, error) {
+	t, err := c.trafficOf(module)
+	if err != nil {
+		return nil, err
+	}
+	return append([]KindHeld{}, t.Kinds...), nil
+}
+
+// SeatWorker is one work queue a holder takes from.
+type SeatWorker struct {
+	Stream   string `json:"Stream"`
+	Consumer string `json:"Consumer"`
+	Filter   string `json:"Filter"`
+}
+
+// ProofTimeout bounds how long a proof waits for its answer.
+var ProofTimeout = 15 * time.Second
+
+// WorkHeartbeat is how often work a bundle is still doing is said to be in progress, well inside the
+// worker's ack wait.
+var WorkHeartbeat = 15 * time.Second
+
+// WorkBackoff is how long a piece of work the bundle did not take waits before it is offered again: from
+// five seconds, doubling, to ten minutes.
+func WorkBackoff(delivered uint64) time.Duration {
+	wait := 5 * time.Second
+	for i := uint64(1); i < delivered && wait < 10*time.Minute; i++ {
+		wait *= 2
+	}
+	return min(wait, 10*time.Minute)
+}
+
+// SubjectMatches is a subject against a permission pattern, in the server's wildcards.
+func SubjectMatches(pattern, subject string) bool {
+	p, s := strings.Split(pattern, "."), strings.Split(subject, ".")
+	for i, part := range p {
+		if part == ">" {
+			return len(s) > i
+		}
+		if i >= len(s) || (part != "*" && part != s[i]) {
+			return false
+		}
+	}
+	return len(p) == len(s)
+}
+
+func (c *Conn) trafficOf(module string) (*SeatTraffic, error) {
+	m := c.Membership(module)
+	if m == nil {
+		return nil, fmt.Errorf("%s has no membership issued on %s yet, so it reaches no seat (novox/hq ADR 0259)",
+			module, c.node)
+	}
+	if m.SeatTraffic == nil {
+		return nil, fmt.Errorf("%s holds, uses and watches no seat that names its caller or its kind (novox/hq "+
+			"ADR 0259): its manifest says so under `uses`, `claims` and `consumes`", module)
+	}
+	return m.SeatTraffic, nil
+}
+
+func listed(patterns []string, subject string) bool {
+	for _, p := range patterns {
+		if SubjectMatches(p, subject) {
+			return true
+		}
+	}
+	return false
+}
+
+// mayPublish refuses a subject the module's seat traffic does not list. A wildcard is never published.
+func (c *Conn) mayPublish(module, subject string) error {
+	t, err := c.trafficOf(module)
+	if err != nil {
+		return err
+	}
+	if strings.ContainsAny(subject, "*>") || !listed(t.Publish, subject) {
+		return fmt.Errorf("%s may not publish %s: a module submits and says only under its own name or kind, "+
+			"and its membership lists %s (novox/hq ADR 0259)", module, subject, strings.Join(t.Publish, ", "))
+	}
+	return nil
+}
+
+func newID() string {
+	var b [16]byte
+	_, _ = rand.Read(b[:])
+	return hex.EncodeToString(b[:])
+}
+
+// SeatPublish submits an accept or says an event on a seat, as the module, into the stream that keeps it,
+// awaited and de-duplicated by its id: the same id twice is one message. A proof is never published here.
+func (c *Conn) SeatPublish(module, subject string, body json.RawMessage, id string) (uint64, error) {
+	seq, _, err := c.SeatPublishSaid(module, subject, body, id)
+	return seq, err
+}
+
+// SeatPublishSaid is SeatPublish, also saying whether the bus took it as a duplicate of one published before
+// under the same id: the same message, kept once.
+func (c *Conn) SeatPublishSaid(module, subject string, body json.RawMessage, id string) (uint64, bool, error) {
+	if strings.Contains(subject, ".proof.") {
+		return 0, false, fmt.Errorf("%s is a proof, asked and answered, never kept: ask it as one", subject)
+	}
+	if err := c.mayPublish(module, subject); err != nil {
+		return 0, false, err
+	}
+	if len(body) == 0 || !json.Valid(body) {
+		return 0, false, fmt.Errorf("what is said on %s is JSON", subject)
+	}
+	if id == "" {
+		id = newID()
+	}
+	// **The publisher's name is part of the id the bus de-duplicates by** (security review 2026-10-08): ids
+	// are the publisher's own, and one module could otherwise suppress another's warrant by publishing first
+	// under the same id.
+	id = module + "." + id
+	msg := nats.NewMsg(subject)
+	msg.Header.Set("x-event-id", id)
+	msg.Header.Set("x-source", module)
+	msg.Header.Set("x-node", c.node)
+	msg.Header.Set("x-time", time.Now().UTC().Format(time.RFC3339Nano))
+	msg.Header.Set("content-type", "application/json")
+	msg.Data = body
+	ack, err := c.js.PublishMsg(msg, nats.MsgId(id))
+	if err != nil {
+		return 0, false, err
+	}
+	return ack.Sequence, ack.Duplicate, nil
+}
+
+// SeatProve asks a proof and answers its reply: core request and reply, on no stream.
+func (c *Conn) SeatProve(module, subject string, body json.RawMessage) (json.RawMessage, error) {
+	if !strings.Contains(subject, ".proof.") {
+		return nil, fmt.Errorf("%s is not a proof", subject)
+	}
+	if err := c.mayPublish(module, subject); err != nil {
+		return nil, err
+	}
+	reply, err := c.nc.Request(subject, body, ProofTimeout)
+	if errors.Is(err, nats.ErrNoResponders) {
+		return nil, fmt.Errorf("nothing answers %s: the module watching the seat is not running", subject)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if !json.Valid(reply.Data) {
+		return nil, fmt.Errorf("the answer to %s is not JSON", subject)
+	}
+	return json.RawMessage(reply.Data), nil
+}
+
+// SeatAnswer answers every proof on a subject the module's seat traffic lists among its answers, with what
+// answer returns. A returned error is answered as `{"error": "<words>"}`, never as silence.
+func (c *Conn) SeatAnswer(module, subject string, answer func(subject string, body json.RawMessage) (json.RawMessage, error)) (func(), error) {
+	t, err := c.trafficOf(module)
+	if err != nil {
+		return nil, err
+	}
+	allowed := false
+	for _, a := range t.Answers {
+		allowed = allowed || a == subject
+	}
+	if !allowed {
+		return nil, fmt.Errorf("%s does not answer %s: its membership lists %s (novox/hq ADR 0259)", module,
+			subject, strings.Join(t.Answers, ", "))
+	}
+	sub, err := c.nc.Subscribe(subject, func(msg *nats.Msg) {
+		if msg.Reply == "" {
+			return
+		}
+		body := json.RawMessage(msg.Data)
+		if !json.Valid(body) {
+			_ = msg.Respond([]byte(`{"error":"a proof is JSON"}`))
+			return
+		}
+		out, err := answer(msg.Subject, body)
+		if err != nil {
+			b, _ := json.Marshal(map[string]string{"error": err.Error()})
+			_ = msg.Respond(b)
+			return
+		}
+		if len(out) == 0 {
+			out = json.RawMessage(`{}`)
+		}
+		if err := msg.Respond(out); err != nil {
+			c.Logf("[mesh-tools] %s could not answer the proof on %s: %v", module, msg.Subject, err)
+		}
+	})
+	if err != nil {
+		return nil, err
+	}
+	c.track(sub)
+	var once sync.Once
+	return func() { once.Do(func() { _ = sub.Unsubscribe() }) }, nil
+}
+
+// Work is one message a holder took from a seat's work queue.
+type Work struct {
+	Worker  string            `json:"worker"`
+	Subject string            `json:"subject"`
+	Body    json.RawMessage   `json:"body"`
+	Headers map[string]string `json:"headers,omitempty"`
+}
+
+// SeatTake reads a worker the module's seat traffic lists and hands each message to deliver: acknowledged
+// when deliver returns nil, offered again after NakDelay when it returns an error, ended when it is not
+// JSON. The worker is the controller's to create; this binds to it by name and never makes one.
+func (c *Conn) SeatTake(module, consumer string, deliver func(Work) error) (func(), error) {
+	t, err := c.trafficOf(module)
+	if err != nil {
+		return nil, err
+	}
+	var w *SeatWorker
+	for i := range t.Workers {
+		if t.Workers[i].Consumer == consumer {
+			w = &t.Workers[i]
+		}
+	}
+	if w == nil {
+		var names []string
+		for _, x := range t.Workers {
+			names = append(names, x.Consumer)
+		}
+		return nil, fmt.Errorf("%s takes no work from %s: its membership lists %s (novox/hq ADR 0259)", module,
+			consumer, strings.Join(names, ", "))
+	}
+	js, err := jetstream.New(c.nc)
+	if err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	bound, err := js.Consumer(ctx, w.Stream, w.Consumer)
+	if err != nil {
+		return nil, fmt.Errorf("binding %s's worker %s on %s: %w", module, w.Consumer, w.Stream, err)
+	}
+	reading, err := bound.Consume(func(msg jetstream.Msg) {
+		if !json.Valid(msg.Data()) {
+			_ = msg.Term()
+			return
+		}
+		headers := map[string]string{}
+		for k := range msg.Headers() {
+			headers[k] = msg.Headers().Get(k)
+		}
+		// Kept alive while the bundle works on it, however long that takes: the ack wait is for a holder
+		// that died, not one that is slow.
+		done := make(chan struct{})
+		go func() {
+			tick := time.NewTicker(WorkHeartbeat)
+			defer tick.Stop()
+			for {
+				select {
+				case <-done:
+					return
+				case <-tick.C:
+					_ = msg.InProgress()
+				}
+			}
+		}()
+		err := deliver(Work{Worker: w.Consumer, Subject: msg.Subject(), Body: json.RawMessage(msg.Data()), Headers: headers})
+		close(done)
+		if err != nil {
+			// Offered again later and later, never given up on: a channel that is away keeps its work
+			// (security and correctness reviews of 2026-10-08).
+			delivered := uint64(1)
+			if meta, merr := msg.Metadata(); merr == nil {
+				delivered = meta.NumDelivered
+			}
+			_ = msg.NakWithDelay(WorkBackoff(delivered))
+			return
+		}
+		_ = msg.Ack()
+	}, jetstream.ConsumeErrHandler(func(_ jetstream.ConsumeContext, err error) {
+		// A worker deleted, or the bus refusing it, is said — never a holder that silently takes nothing.
+		c.Logf("[mesh-tools] %s's worker %s: %v", module, w.Consumer, err)
+	}))
+	if err != nil {
+		return nil, fmt.Errorf("reading %s's worker %s: %w", module, w.Consumer, err)
+	}
+	var once sync.Once
+	return func() { once.Do(reading.Stop) }, nil
+}
+
+// SeatRecord reads one key of a record a seat keeps for the module, under its own name: the bucket's
+// current value of `<module>.<key>`, or nil when there is none.
+func (c *Conn) SeatRecord(module, bucket, key string) (*StateEntry, error) {
+	t, err := c.trafficOf(module)
+	if err != nil {
+		return nil, err
+	}
+	if err := checkKey(key); err != nil {
+		return nil, err
+	}
+	if bucket == "" {
+		// The one record its membership lists, when it lists one: an asker reads the router's asks without
+		// knowing the router's name.
+		var named []string
+		for _, r := range t.Records {
+			if b, _, ok := strings.Cut(strings.TrimPrefix(r, "$JS.API.DIRECT.GET.KV_"), "."); ok {
+				named = append(named, b)
+			}
+		}
+		if len(named) != 1 {
+			return nil, fmt.Errorf("%s reads %d records under its name; name the one meant", module, len(named))
+		}
+		bucket = named[0]
+	}
+	subject := "$JS.API.DIRECT.GET.KV_" + bucket + ".$KV." + bucket + "." + module + "." + key
+	if !listed(t.Records, subject) {
+		return nil, fmt.Errorf("%s reads no record of %s under its name: its membership lists %s (novox/hq ADR 0259)",
+			module, bucket, strings.Join(t.Records, ", "))
+	}
+	reply, err := c.nc.Request(subject, nil, StateTimeout)
+	if err != nil {
+		return nil, err
+	}
+	if status := reply.Header.Get("Status"); status == "404" {
+		return nil, nil
+	} else if status != "" {
+		return nil, fmt.Errorf("the record %s.%s could not be read: %s %s", module, key, status, reply.Header.Get("Description"))
+	}
+	if op := reply.Header.Get("KV-Operation"); op == "DEL" || op == "PURGE" {
+		return nil, nil
+	}
+	var revision uint64
+	fmt.Sscan(reply.Header.Get("Nats-Sequence"), &revision)
+	return &StateEntry{Key: module + "." + key, Value: valueOf(reply.Data), Revision: revision}, nil
+}
+
+// StateCreate writes one key only when it has no value, and answers its revision; a key that has one is
+// refused, naming it, so two writers racing to make it are one winner and one refusal.
+func (c *Conn) StateCreate(module, name, key string, value json.RawMessage) (uint64, error) {
+	return c.stateWrite(module, name, key, value, func(ctx context.Context, kv jetstream.KeyValue) (uint64, error) {
+		return kv.Create(ctx, key, value)
+	})
+}
+
+// StateUpdate writes one key only when its revision is still the one given, and answers the new revision;
+// a key changed meanwhile is refused, so of two writers that read one value only the first writes.
+func (c *Conn) StateUpdate(module, name, key string, value json.RawMessage, revision uint64) (uint64, error) {
+	if revision == 0 {
+		// Revision zero would be read by the server as "the key is new": an update names the value it read.
+		return 0, fmt.Errorf("an update names the revision it read; zero is none — create the key instead")
+	}
+	return c.stateWrite(module, name, key, value, func(ctx context.Context, kv jetstream.KeyValue) (uint64, error) {
+		return kv.Update(ctx, key, value, revision)
+	})
+}
+
+// ErrStateChanged is a compare-and-set that lost: the key was made or changed by another writer first.
+var ErrStateChanged = errors.New("the key was written by another writer first")
+
+// changed is ErrStateChanged naming the key, with the code a bundle is answered it by.
+type changed struct{ key string }
+
+func (e changed) Error() string        { return e.key + ": " + ErrStateChanged.Error() }
+func (e changed) Is(target error) bool { return target == ErrStateChanged }
+func (e changed) ErrorCode() int       { return -32010 }
+
+func (c *Conn) stateWrite(module, name, key string, value json.RawMessage,
+	write func(context.Context, jetstream.KeyValue) (uint64, error)) (uint64, error) {
+	s, err := c.writable(module, name)
+	if err != nil {
+		return 0, err
+	}
+	if err := checkKey(key); err != nil {
+		return 0, err
+	}
+	if len(value) == 0 || !json.Valid(value) {
+		return 0, fmt.Errorf("a state value is JSON")
+	}
+	if field := credentialField(value); field != "" {
+		return 0, fmt.Errorf("%s's %s.%s carries a field %q, which names a credential: no secret is kept in state "+
+			"(novox/hq ADR 0201)", module, name, key, field)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	kv, err := c.bucket(ctx, s)
+	if err != nil {
+		return 0, err
+	}
+	rev, err := write(ctx, kv)
+	if errors.Is(err, jetstream.ErrKeyExists) || isWrongSequence(err) {
+		return 0, changed{name + "." + key}
+	}
+	return rev, err
+}
+
+// isWrongSequence is the server's refusal of an update whose revision is not the key's last.
+func isWrongSequence(err error) bool {
+	var api *jetstream.APIError
+	return errors.As(err, &api) && api.ErrorCode == jetstream.JSErrCodeStreamWrongLastSequence
+}

node-tools/internal/bus/seat_test.go

@@ -0,0 +1,239 @@
+package bus_test
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// The seats of novox/hq ADR 0259 §3 as the controller issues them: an asker, the router, and a channel of
+// kind telegram, each with the seat traffic its membership lists.
+func seatMesh(t *testing.T) (*mt.Mesh, *bus.Conn, nats.JetStreamContext) {
+	t.Helper()
+	mesh := mt.New(t)
+	nc, err := nats.Connect(mt.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(nc.Close)
+	js, _ := nc.JetStream()
+	for _, s := range []*nats.StreamConfig{
+		{Name: "SEAT_OPERATOR_CHANNEL", Subjects: []string{"mesh.seat.operator-channel.accept.>"}, Retention: nats.WorkQueuePolicy},
+		{Name: "SEAT_CHANNEL", Subjects: []string{"mesh.seat.channel.accept.>"}, Retention: nats.WorkQueuePolicy},
+		{Name: "SEAT_EVENTS", Subjects: []string{"mesh.seat.*.event.>"}},
+	} {
+		if _, err := js.AddStream(s); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for stream, c := range map[string]*nats.ConsumerConfig{
+		"SEAT_OPERATOR_CHANNEL": {Durable: "SEAT_OPERATOR_CHANNEL_worker", AckPolicy: nats.AckExplicitPolicy,
+			FilterSubject: "mesh.seat.operator-channel.accept.>", AckWait: 2 * time.Second},
+		"SEAT_CHANNEL": {Durable: "SEAT_CHANNEL_TELEGRAM_worker", AckPolicy: nats.AckExplicitPolicy,
+			FilterSubject: "mesh.seat.channel.accept.*.telegram", AckWait: 2 * time.Second},
+	} {
+		if _, err := js.AddConsumer(stream, c); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if _, err := js.CreateKeyValue(&nats.KeyValueConfig{Bucket: "messenger_asks"}); err != nil {
+		t.Fatal(err)
+	}
+
+	asker := mt.MembershipOf("mesh-delivery", "anchor", false, nil)
+	asker.SeatTraffic = &bus.SeatTraffic{
+		Publish:   []string{"mesh.seat.operator-channel.accept.ask.mesh-delivery"},
+		Subscribe: []string{"mesh.seat.operator-channel.event.decided.mesh-delivery"},
+		Records:   []string{"$JS.API.DIRECT.GET.KV_messenger_asks.$KV.messenger_asks.mesh-delivery.>"},
+	}
+	router := mt.MembershipOf("messenger", "anchor", false, nil)
+	router.SeatTraffic = &bus.SeatTraffic{
+		Publish: []string{"mesh.seat.operator-channel.event.decided.*", "mesh.seat.channel.accept.show.*"},
+		Answers: []string{"mesh.seat.intake.proof.code.*"},
+		Workers: []bus.SeatWorker{{Stream: "SEAT_OPERATOR_CHANNEL", Consumer: "SEAT_OPERATOR_CHANNEL_worker",
+			Filter: "mesh.seat.operator-channel.accept.>"}},
+	}
+	router.State = []bus.StateIssued{{Name: "asks", Bucket: "messenger_asks", Writes: true}}
+	telegram := mt.MembershipOf("telegram", "anchor", false, nil)
+	telegram.SeatTraffic = &bus.SeatTraffic{
+		Publish: []string{"mesh.seat.intake.event.choice.telegram", "mesh.seat.intake.proof.code.telegram"},
+		Workers: []bus.SeatWorker{{Stream: "SEAT_CHANNEL", Consumer: "SEAT_CHANNEL_TELEGRAM_worker",
+			Filter: "mesh.seat.channel.accept.*.telegram"}},
+	}
+	for _, m := range []bus.Membership{asker, router, telegram} {
+		mesh.Issue(t, m)
+	}
+	conn, err := bus.Connect(bus.Credential{URL: mt.URL(t), Module: "node-tools", Node: "anchor"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	conn.Logf = func(string, ...any) {}
+	t.Cleanup(conn.Close)
+	for _, m := range []string{"mesh-delivery", "messenger", "telegram"} {
+		conn.Follow(m)
+	}
+	mt.Until(t, func() error {
+		for _, m := range []string{"mesh-delivery", "messenger", "telegram"} {
+			if conn.Membership(m) == nil {
+				return errors.New(m + " not issued yet")
+			}
+		}
+		return nil
+	})
+	return mesh, conn, js
+}
+
+func TestAModuleSubmitsAndSaysOnlyUnderItsOwnNameAndKind(t *testing.T) {
+	_, conn, _ := seatMesh(t)
+	body := json.RawMessage(`{"id":"a1"}`)
+	if _, err := conn.SeatPublish("mesh-delivery", "mesh.seat.operator-channel.accept.ask.mesh-delivery", body, "a1"); err != nil {
+		t.Fatalf("an asker could not ask under its own name: %v", err)
+	}
+	for module, subject := range map[string]string{
+		"mesh-delivery": "mesh.seat.operator-channel.accept.ask.mesh-controller",
+		"telegram":      "mesh.seat.intake.event.choice.desktop",
+		"messenger":     "mesh.seat.intake.event.choice.telegram",
+	} {
+		if _, err := conn.SeatPublish(module, subject, body, ""); err == nil || !strings.Contains(err.Error(), "may not publish") {
+			t.Errorf("%s published %s: %v", module, subject, err)
+		}
+	}
+	if _, err := conn.SeatPublish("messenger", "mesh.seat.operator-channel.event.decided.*", body, ""); err == nil {
+		t.Error("a wildcard was published")
+	}
+	if _, err := conn.SeatPublish("telegram", "mesh.seat.intake.proof.code.telegram", body, ""); err == nil ||
+		!strings.Contains(err.Error(), "never kept") {
+		t.Errorf("a proof was published onto a stream: %v", err)
+	}
+}
+
+func TestTheHolderTakesItsWorkOnceAndAFailureComesBack(t *testing.T) {
+	_, conn, _ := seatMesh(t)
+	if _, err := conn.SeatPublish("mesh-delivery", "mesh.seat.operator-channel.accept.ask.mesh-delivery",
+		json.RawMessage(`{"id":"a1"}`), "a1"); err != nil {
+		t.Fatal(err)
+	}
+	// The same id again is one ask: a retry after a lost answer does not ask twice.
+	if _, err := conn.SeatPublish("mesh-delivery", "mesh.seat.operator-channel.accept.ask.mesh-delivery",
+		json.RawMessage(`{"id":"a1"}`), "a1"); err != nil {
+		t.Fatal(err)
+	}
+	var mu sync.Mutex
+	var got []string
+	fail := true
+	stop, err := conn.SeatTake("messenger", "SEAT_OPERATOR_CHANNEL_worker", func(w bus.Work) error {
+		mu.Lock()
+		defer mu.Unlock()
+		got = append(got, w.Subject+" from "+w.Headers["x-source"])
+		if fail {
+			fail = false
+			return errors.New("not recorded")
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	deadline := time.Now().Add(15 * time.Second)
+	for {
+		mu.Lock()
+		n := len(got)
+		mu.Unlock()
+		if n >= 2 || time.Now().After(deadline) {
+			break
+		}
+		time.Sleep(50 * time.Millisecond)
+	}
+	time.Sleep(500 * time.Millisecond)
+	mu.Lock()
+	defer mu.Unlock()
+	if len(got) != 2 || got[0] != "mesh.seat.operator-channel.accept.ask.mesh-delivery from mesh-delivery" || got[0] != got[1] {
+		t.Fatalf("want the one ask, offered again after the failure: %v", got)
+	}
+	if _, err := conn.SeatTake("telegram", "SEAT_OPERATOR_CHANNEL_worker", func(bus.Work) error { return nil }); err == nil {
+		t.Error("a channel took the router's work")
+	}
+}
+
+func TestAProofIsAskedAndAnsweredAndNeverKept(t *testing.T) {
+	_, conn, js := seatMesh(t)
+	stop, err := conn.SeatAnswer("messenger", "mesh.seat.intake.proof.code.*", func(subject string, body json.RawMessage) (json.RawMessage, error) {
+		if !strings.HasSuffix(subject, ".telegram") {
+			return nil, errors.New("asked by another kind")
+		}
+		return json.RawMessage(`{"linked":true}`), nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	var answer json.RawMessage
+	mt.Until(t, func() error {
+		answer, err = conn.SeatProve("telegram", "mesh.seat.intake.proof.code.telegram", json.RawMessage(`{"code":"123456"}`))
+		return err
+	})
+	if string(answer) != `{"linked":true}` {
+		t.Fatalf("the proof was answered %s", answer)
+	}
+	if _, err := conn.SeatProve("telegram", "mesh.seat.intake.proof.code.desktop", json.RawMessage(`{}`)); err == nil {
+		t.Error("a channel asked a proof as another kind")
+	}
+	if _, err := conn.SeatAnswer("telegram", "mesh.seat.intake.proof.code.*", nil); err == nil {
+		t.Error("a channel answers proofs")
+	}
+	for name := range js.StreamNames() {
+		info, _ := js.StreamInfo(name)
+		for _, s := range info.Config.Subjects {
+			if bus.SubjectMatches(s, "mesh.seat.intake.proof.code.telegram") {
+				t.Errorf("%s keeps proofs", name)
+			}
+		}
+	}
+}
+
+func TestAnAskerReadsItsOwnRecordAndNoOther(t *testing.T) {
+	_, conn, js := seatMesh(t)
+	kv, _ := js.KeyValue("messenger_asks")
+	if _, err := kv.Put("mesh-delivery.a1", []byte(`{"state":"open"}`)); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := kv.Put("mesh-controller.a1", []byte(`{"state":"open"}`)); err != nil {
+		t.Fatal(err)
+	}
+	got, err := conn.SeatRecord("mesh-delivery", "messenger_asks", "a1")
+	if err != nil || got == nil || string(got.Value) != `{"state":"open"}` {
+		t.Fatalf("the asker could not read its own ask: %v %v", got, err)
+	}
+	if missing, err := conn.SeatRecord("mesh-delivery", "messenger_asks", "a2"); err != nil || missing != nil {
+		t.Fatalf("a missing ask read as %v, %v", missing, err)
+	}
+	if _, err := conn.SeatRecord("telegram", "messenger_asks", "a1"); err == nil {
+		t.Error("a module read records it is not given")
+	}
+}
+
+func TestOfTwoAnswersToOneAskOnlyTheFirstIsWritten(t *testing.T) {
+	_, conn, _ := seatMesh(t)
+	rev, err := conn.StateCreate("messenger", "asks", "mesh-delivery.a1", json.RawMessage(`{"state":"open"}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := conn.StateCreate("messenger", "asks", "mesh-delivery.a1", json.RawMessage(`{"state":"open"}`)); !errors.Is(err, bus.ErrStateChanged) {
+		t.Errorf("a second create stood: %v", err)
+	}
+	if _, err := conn.StateUpdate("messenger", "asks", "mesh-delivery.a1", json.RawMessage(`{"state":"answered"}`), rev); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := conn.StateUpdate("messenger", "asks", "mesh-delivery.a1", json.RawMessage(`{"state":"answered"}`), rev); !errors.Is(err, bus.ErrStateChanged) {
+		t.Errorf("a second answer from the same revision stood: %v", err)
+	}
+}

node-tools/internal/bus/state.go

@@ -0,0 +1,401 @@
+package bus
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"regexp"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// A module's state on the bus (novox/hq ADR 0201): key-value buckets the controller creates from what
+// the module declared, and issues to each assignment in its membership by the name the module uses —
+// its own state by the local name, another module's as `<module>.<name>`.
+//
+// **The runtime keeps each module to its own buckets.** One account per machine carries every module
+// on it, so the bus enforces only the union; and a write the bus refuses reaches the writer as a
+// timeout, not a refusal (measured, novox/hq research 024). So what a module may reach is decided here,
+// from its membership, and refused with the reason before anything is sent.
+
+// StateIssued is one bucket an assignment may reach (ADR 0201).
+type StateIssued struct {
+	Name   string `json:"name"`
+	Bucket string `json:"bucket"`
+	Writes bool   `json:"writes,omitempty"`
+}
+
+// StateEntry is one key's current value.
+type StateEntry struct {
+	Key      string          `json:"key"`
+	Value    json.RawMessage `json:"value"`
+	Revision uint64          `json:"revision"`
+}
+
+// StateChange is one change a watch delivers: a key put or deleted.
+type StateChange struct {
+	State    string          `json:"state"`
+	Key      string          `json:"key"`
+	Op       string          `json:"op"`
+	Value    json.RawMessage `json:"value,omitempty"`
+	Revision uint64          `json:"revision"`
+	// Current is true for a value that was there when the watch began, false for a change since.
+	Current bool `json:"current"`
+}
+
+// StateTimeout bounds one state operation on the bus.
+var StateTimeout = 10 * time.Second
+
+// stateKey is a key the bus can hold: letters, digits and `-/_=.`, no leading or trailing dot. A
+// module's convention for naming a machine in a key (`all.<server>`, `<machine>.<server>`) fits it.
+var stateKey = regexp.MustCompile(`^[-/_=a-zA-Z0-9]+(\.[-/_=a-zA-Z0-9]+)*$`)
+
+// issuedState is the bucket a module may reach by a name, and whether it may write it — or the reason
+// it may not reach it at all.
+func (c *Conn) issuedState(module, name string) (StateIssued, error) {
+	m := c.Membership(module)
+	if m == nil {
+		return StateIssued{}, fmt.Errorf("%s has no membership issued on %s yet, so no state of it is reachable "+
+			"until the mesh issues one (novox/hq ADR 0201)", module, c.node)
+	}
+	var names []string
+	for _, s := range m.State {
+		if s.Name == name {
+			return s, nil
+		}
+		names = append(names, s.Name)
+	}
+	sort.Strings(names)
+	issued := "none"
+	if len(names) > 0 {
+		issued = strings.Join(names, ", ")
+	}
+	return StateIssued{}, fmt.Errorf("%s keeps and reads no state called %q: it declares what it keeps under "+
+		"`state` and what it reads under `reads` as <module>.<name>, and was issued: %s (novox/hq ADR 0201)",
+		module, name, issued)
+}
+
+func (c *Conn) bucket(ctx context.Context, s StateIssued) (jetstream.KeyValue, error) {
+	js, err := jetstream.New(c.nc)
+	if err != nil {
+		return nil, err
+	}
+	kv, err := js.KeyValue(ctx, s.Bucket)
+	if err != nil {
+		if errors.Is(err, jetstream.ErrBucketNotFound) {
+			return nil, fmt.Errorf("the state %q is issued and its bucket is not on the bus yet: the controller "+
+				"creates it from the catalogue on its next raise", s.Name)
+		}
+		return nil, err
+	}
+	return kv, nil
+}
+
+func checkKey(key string) error {
+	if !stateKey.MatchString(key) {
+		return fmt.Errorf("%q is not a key the bus can hold: letters, digits and -/_=, in dot-separated "+
+			"names", key)
+	}
+	return nil
+}
+
+// StateGet is one key's current value, or nil when it has none.
+func (c *Conn) StateGet(module, name, key string) (*StateEntry, error) {
+	s, err := c.issuedState(module, name)
+	if err != nil {
+		return nil, err
+	}
+	if err := checkKey(key); err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	kv, err := c.bucket(ctx, s)
+	if err != nil {
+		return nil, err
+	}
+	e, err := kv.Get(ctx, key)
+	if errors.Is(err, jetstream.ErrKeyNotFound) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &StateEntry{Key: e.Key(), Value: valueOf(e.Value()), Revision: e.Revision()}, nil
+}
+
+// StateKept is one value a bucket still keeps for a key: a put, or a delete (a purge reads as one).
+type StateKept struct {
+	Key      string          `json:"key"`
+	Value    json.RawMessage `json:"value,omitempty"`
+	Revision uint64          `json:"revision"`
+	Op       string          `json:"op"`
+	At       time.Time       `json:"at"`
+}
+
+// StateHistory is every value the bucket still keeps for one key, oldest first, or none (novox/hq ADR
+// 0307). It is a read like StateGet: served to the owner and to every reader, and writes nothing.
+func (c *Conn) StateHistory(module, name, key string) ([]StateKept, error) {
+	s, err := c.issuedState(module, name)
+	if err != nil {
+		return nil, err
+	}
+	if err := checkKey(key); err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	kv, err := c.bucket(ctx, s)
+	if err != nil {
+		return nil, err
+	}
+	entries, err := kv.History(ctx, key)
+	kept := []StateKept{}
+	if errors.Is(err, jetstream.ErrKeyNotFound) {
+		return kept, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	for _, e := range entries {
+		k := StateKept{Key: e.Key(), Revision: e.Revision(), Op: "delete", At: e.Created().UTC()}
+		if e.Operation() == jetstream.KeyValuePut {
+			k.Op = "put"
+			k.Value = valueOf(e.Value())
+		}
+		kept = append(kept, k)
+	}
+	return kept, nil
+}
+
+// StatePut writes one key, as the module, where the module keeps the state. It answers the revision.
+func (c *Conn) StatePut(module, name, key string, value json.RawMessage) (uint64, error) {
+	s, err := c.writable(module, name)
+	if err != nil {
+		return 0, err
+	}
+	if err := checkKey(key); err != nil {
+		return 0, err
+	}
+	if len(value) == 0 || !json.Valid(value) {
+		return 0, fmt.Errorf("a state value is JSON")
+	}
+	if field := credentialField(value); field != "" {
+		return 0, fmt.Errorf("%s's %s.%s carries a field %q, which names a credential: no secret is kept in state, "+
+			"sealed or not — a bucket is a stream, and a machine joining a year later reads it whole. Name the "+
+			"secret and fetch it on request/reply (novox/hq ADR 0201, design 32 §10)", module, name, key, field)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	kv, err := c.bucket(ctx, s)
+	if err != nil {
+		return 0, err
+	}
+	return kv.Put(ctx, key, value)
+}
+
+// StateDelete removes one key, as the module, where the module keeps the state. A key that was not
+// there is not an error: what is asked for is that it is gone.
+func (c *Conn) StateDelete(module, name, key string) error {
+	s, err := c.writable(module, name)
+	if err != nil {
+		return err
+	}
+	if err := checkKey(key); err != nil {
+		return err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	kv, err := c.bucket(ctx, s)
+	if err != nil {
+		return err
+	}
+	return kv.Delete(ctx, key)
+}
+
+// StateKeys is every key with a current value, sorted.
+func (c *Conn) StateKeys(module, name string) ([]string, error) {
+	s, err := c.issuedState(module, name)
+	if err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	kv, err := c.bucket(ctx, s)
+	if err != nil {
+		return nil, err
+	}
+	lister, err := kv.ListKeys(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = lister.Stop() }()
+	keys := []string{}
+	for k := range lister.Keys() {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	return keys, nil
+}
+
+func (c *Conn) writable(module, name string) (StateIssued, error) {
+	s, err := c.issuedState(module, name)
+	if err != nil {
+		return s, err
+	}
+	if !s.Writes {
+		owner := name
+		if dot := strings.LastIndex(name, "."); dot > 0 {
+			owner = name[:dot]
+		}
+		return s, fmt.Errorf("%s reads %s and does not keep it: only %s's own instances write it (novox/hq ADR 0201)",
+			module, name, owner)
+	}
+	return s, nil
+}
+
+// StateWatch hands deliver the current value of every key matching the pattern — none that is
+// deleted — and then every change, in order (ADR 0201). It returns once the current values are
+// delivered; deliver is called from one goroutine, one change at a time, and an error from it is said
+// and the watch goes on: state is not a queue, and the next change, or the next start, reads it again.
+// The pattern is a key, with `*` for one name and `**` for the rest; empty is every key.
+func (c *Conn) StateWatch(module, name, pattern string, deliver func(StateChange) error) (stop func(), err error) {
+	s, err := c.issuedState(module, name)
+	if err != nil {
+		return nil, err
+	}
+	filter := ">"
+	if pattern != "" {
+		parts := strings.Split(pattern, ".")
+		for i, p := range parts {
+			if p == "**" {
+				if i != len(parts)-1 {
+					return nil, fmt.Errorf("%q: `**` stands for the rest of a key, so it comes last", pattern)
+				}
+				parts[i] = ">"
+				continue
+			}
+			if p != "*" && !stateKey.MatchString(p) {
+				return nil, fmt.Errorf("%q is not a key pattern: names, `*` for one and `**` for the rest", pattern)
+			}
+		}
+		filter = strings.Join(parts, ".")
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	kv, err := c.bucket(ctx, s)
+	cancel()
+	if err != nil {
+		return nil, err
+	}
+	watching, stopWatching := context.WithCancel(context.Background())
+	w, err := kv.Watch(watching, filter)
+	if err != nil {
+		stopWatching()
+		return nil, err
+	}
+	var once sync.Once
+	stop = func() {
+		once.Do(func() {
+			_ = w.Stop()
+			stopWatching()
+		})
+	}
+	current := make(chan struct{})
+	go func() {
+		initial := true
+		for e := range w.Updates() {
+			if e == nil {
+				// The end of what was there when the watch began.
+				if initial {
+					initial = false
+					close(current)
+				}
+				continue
+			}
+			change := StateChange{State: name, Key: e.Key(), Revision: e.Revision(), Current: initial}
+			switch e.Operation() {
+			case jetstream.KeyValuePut:
+				change.Op = "put"
+				change.Value = valueOf(e.Value())
+			default:
+				// A deletion among the current values is a key that is not there: not handed over
+				// (measured, research 024 — the server sends its marker among the initial values).
+				if initial {
+					continue
+				}
+				change.Op = "delete"
+			}
+			if err := deliver(change); err != nil {
+				c.Logf("[mesh-tools] %s did not take %s %s of %s: %v; its next change, or its next start, reads it again",
+					module, change.Op, change.Key, name, err)
+			}
+		}
+		if initial {
+			close(current)
+		}
+	}()
+	select {
+	case <-current:
+		return stop, nil
+	case <-time.After(StateTimeout):
+		stop()
+		return nil, fmt.Errorf("the current values of %s did not arrive in %s", name, StateTimeout)
+	}
+}
+
+func valueOf(raw []byte) json.RawMessage {
+	if len(raw) == 0 || !json.Valid(raw) {
+		b, _ := json.Marshal(string(raw))
+		return b
+	}
+	return json.RawMessage(raw)
+}
+
+// credentialEndings are the ends of a field name that say its value is a credential. A guard against
+// the ordinary mistake, not a determined one: a sealed value is plain text to anything inspecting it,
+// so the rule is checked where it can be and said to be partial (ADR 0201).
+var credentialEndings = []string{"password", "passwd", "secret", "token", "credential", "credentials",
+	"authorization", "apikey", "privatekey", "accesskey", "cookie"}
+
+// credentialField is the first field anywhere in a JSON value whose name says it is a credential, or "".
+func credentialField(value json.RawMessage) string {
+	var v any
+	if json.Unmarshal(value, &v) != nil {
+		return ""
+	}
+	var walk func(any) string
+	walk = func(v any) string {
+		switch t := v.(type) {
+		case map[string]any:
+			keys := make([]string, 0, len(t))
+			for k := range t {
+				keys = append(keys, k)
+			}
+			sort.Strings(keys)
+			for _, k := range keys {
+				norm := strings.NewReplacer("-", "", "_", "", " ", "").Replace(strings.ToLower(k))
+				for _, end := range credentialEndings {
+					if strings.HasSuffix(norm, end) {
+						return k
+					}
+				}
+				if found := walk(t[k]); found != "" {
+					return found
+				}
+			}
+		case []any:
+			for _, x := range t {
+				if found := walk(x); found != "" {
+					return found
+				}
+			}
+		}
+		return ""
+	}
+	return walk(v)
+}

node-tools/internal/bus/state_test.go

@@ -0,0 +1,23 @@
+package bus
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// A value naming a credential anywhere in it is found (novox/hq ADR 0201) — the guard against the
+// ordinary mistake — and a value that only mentions tokens as a count is not.
+func TestACredentialNamedFieldIsFoundAnywhereInAValue(t *testing.T) {
+	for value, want := range map[string]string{
+		`{"url":"http://x","headers":{"Authorization":"Bearer s"}}`: "Authorization",
+		`[{"name":"a","env":{"API_KEY":"s"}}]`:                      "API_KEY",
+		`{"refresh_token":"s"}`:                                     "refresh_token",
+		`{"clientSecret":"s"}`:                                      "clientSecret",
+		`{"maxTokens":4096,"name":"a","generation":3}`:              "",
+		`"just a string"`:                                           "",
+	} {
+		if got := credentialField(json.RawMessage(value)); got != want {
+			t.Errorf("%s: found %q, want %q", value, got, want)
+		}
+	}
+}

node-tools/internal/console/address_test.go

@@ -0,0 +1,243 @@
+package console
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+	"github.com/novox/mesh-tools/node-tools/internal/runtime"
+)
+
+// text is a tool result's first text, and whether it was an error.
+func text(t *testing.T, reply map[string]any) (string, bool) {
+	t.Helper()
+	result, ok := reply["result"].(map[string]any)
+	if !ok {
+		t.Fatalf("no result: %v", reply)
+	}
+	content := result["content"].([]any)
+	isErr, _ := result["isError"].(bool)
+	var parts []string
+	for _, c := range content {
+		parts = append(parts, c.(map[string]any)["text"].(string))
+	}
+	return strings.Join(parts, "\n"), isErr
+}
+
+func call(t *testing.T, endpoint, tool string, args map[string]any) (string, bool) {
+	t.Helper()
+	body, _ := json.Marshal(map[string]any{"jsonrpc": "2.0", "id": 9, "method": "tools/call",
+		"params": map[string]any{"name": tool, "arguments": args}})
+	return text(t, post(t, endpoint, string(body)))
+}
+
+// novox/hq ADR 0195: the console announces six tools, and everything the mesh answers is reached
+// through them by one address per layer.
+func TestTheMeshsToolsAreFoundByAddress(t *testing.T) {
+	was := IndexKept
+	IndexKept = 0 // every discovery asks the mesh, so a module arriving mid-test is found
+	t.Cleanup(func() { IndexKept = was })
+
+	mesh := mt.New(t)
+	// alpha: interchangeable (the mesh issued it a plain subject); beta: state on its machine, holds
+	// the node-shelf seat there.
+	mesh.Issue(t, mt.MembershipOf("alpha", "desk", true, nil))
+	mesh.Issue(t, mt.MembershipOf("beta", "desk", false, map[string][]string{"node-shelf": {"list", "clear"}}))
+	nodeTools := connect(t, "node-tools", "desk")
+	stop, err := runtime.Run(nodeTools, []runtime.Served{
+		{Module: "alpha", Entrypoints: []string{mt.Fixture("many-alpha.serve.mjs")}},
+		{Module: "beta", Entrypoints: []string{mt.Fixture("many-beta.serve.mjs")}},
+	}, nil, (&mt.Logs{}).Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+
+	// Nothing may be asked for a roster or a module's `tools` any more (ADR 0197): counted.
+	var asked atomic.Int32
+	watcher := connect(t, "watcher", "")
+	for _, subject := range []string{"mesh.mod.*.tool.tools", "mesh.mod.*.tool.tools.*", "mesh.mod.mesh-catalog.>"} {
+		stop, err := watcher.Raw(subject, func(string, []byte) []byte { asked.Add(1); return nil })
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+
+	// The controller: its records as JSON, as its seat verbs answer them, and its own seat's verbs
+	// announced on the bus like every runtime's.
+	controller := connect(t, "mesh-controller", "bench")
+	out := func(s string) map[string]any { return map[string]any{"output": s, "ok": true} }
+	serve := func(verb string, answer func() any) {
+		stop, err := controller.HandleSubject("mesh.seat.mesh-controller.tool."+verb, func(json.RawMessage) (any, error) {
+			return answer(), nil
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+	serve("nodes", func() any {
+		return out("the bus's user list leaves out 2 user(s)\n" +
+			`[{"name":"bench","heard":"3m ago","mode":"converged","id":"1f2e"},{"name":"desk","heard":"here","mode":"converged","id":"9a8b"}]`)
+	})
+	var gammaOn atomic.Value
+	gammaOn.Store("[]")
+	serve("modules", func() any {
+		return out(fmt.Sprintf(`[{"module":"alpha","on":["desk"],"tools":true},{"module":"beta","on":["desk"],"tools":true},`+
+			`{"module":"gamma","on":%s,"tools":true},{"module":"delta","on":["desk"],"tools":false},`+
+			`{"module":"epsilon","on":["bench"],"tools":true},{"module":"mesh-controller","on":["bench"],"tools":true}]`, gammaOn.Load().(string)))
+	})
+	stopAnn, err := announce.Serve(controller, announce.Service{Name: "mesh-controller", ID: "bench"}, func() []announce.Endpoint {
+		return []announce.Endpoint{{Kind: announce.KindSeat, Module: "mesh-controller", Seat: "mesh-controller", Scope: "mesh",
+			// As the live controller announces: a mesh seat's holder names no machine.
+			Tool: "nodes", Node: "", Description: "Every machine the mesh knows.", Schema: json.RawMessage(`{}`),
+			Subject: "mesh.seat.mesh-controller.tool.nodes"}}
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopAnn)
+	controller.Flush()
+	watcher.Flush()
+
+	up, err := Serve(NewSurface(nodeTools, "desk.node-tools"), "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer up.Close()
+	endpoint := "http://" + up.Address + "/mcp"
+
+	// Six tools, nothing else.
+	listed := post(t, endpoint, `{"jsonrpc":"2.0","id":2,"method":"tools/list"}`)["result"].(map[string]any)
+	var names []string
+	for _, x := range listed["tools"].([]any) {
+		name := x.(map[string]any)["name"].(string)
+		names = append(names, name)
+		for _, r := range name {
+			if !(r >= 'a' && r <= 'z' || r >= 'A' && r <= 'Z' || r >= '0' && r <= '9' || r == '_' || r == '-') || len(name) > 64 {
+				t.Errorf("%q is not a name the API takes", name)
+			}
+		}
+	}
+	if got := strings.Join(names, ","); got != "mesh_overview,mesh_machine,mesh_search,mesh_describe,mesh_call,mesh_runtimes" {
+		t.Errorf("announced %s", got)
+	}
+
+	// The overview names the mesh's seats, the machines' seats and the machines.
+	overview, isErr := call(t, endpoint, "mesh_overview", nil)
+	if isErr || !strings.Contains(overview, "mesh-controller.nodes") || !strings.Contains(overview, "<node>/node-shelf.list") ||
+		!strings.Contains(overview, `"bench"`) || !strings.Contains(overview, `"desk"`) {
+		t.Errorf("overview: %s", overview)
+	}
+	// Silence is named only where tools should have answered: epsilon declares tools on bench and
+	// nothing there announced it; delta declares none and is never a name.
+	if strings.Contains(overview, "mesh-controller on bench") {
+		t.Errorf("a mesh seat's holder that announced no machine is called silent on its machine:\n%s", overview)
+	}
+	if !strings.Contains(overview, "epsilon on bench") || strings.Contains(overview, "delta") {
+		t.Errorf("not answering: %s", overview)
+	}
+	machine, isErr := call(t, endpoint, "mesh_machine", map[string]any{"node": "desk"})
+	if isErr || !strings.Contains(machine, "desk/node-shelf.list") || !strings.Contains(machine, "desk/beta.three") ||
+		!strings.Contains(machine, "desk/alpha.one") {
+		t.Errorf("machine: %s", machine)
+	}
+
+	// A mesh seat, a node seat, an assignment and an interchangeable module, each by address.
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "mesh-controller.nodes"}); isErr || !strings.Contains(got, "converged") {
+		t.Errorf("mesh seat: %s", got)
+	}
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "desk/node-shelf.list"}); isErr || !strings.Contains(got, `"a"`) {
+		t.Errorf("node seat: %s", got)
+	}
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "desk/beta.three"}); isErr ||
+		!strings.Contains(got, `"beta": 3`) || !strings.Contains(got, "answered by desk") {
+		t.Errorf("assignment: %s", got)
+	}
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "alpha.one"}); isErr || !strings.Contains(got, `"alpha": 1`) {
+		t.Errorf("interchangeable module: %s", got)
+	}
+
+	// Refused, by name, where the address does not say enough or says the wrong thing.
+	for address, want := range map[string]string{
+		"beta.three":                 "keeps state on each machine it runs on, so a call names the machine: write <node>/beta.three — it runs on desk",
+		"node-shelf.list":            "held once per machine: write <node>/node-shelf.list — it is held on desk",
+		"desk/mesh-controller.nodes": "held once for the whole mesh",
+		"bench/beta.three":           "beta does not run on bench; it runs on desk",
+		"nonsense":                   "is not an address",
+	} {
+		got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": address})
+		if !isErr || !strings.Contains(got, want) {
+			t.Errorf("%s: %s (want %q)", address, got, want)
+		}
+	}
+
+	// Discovery itself asked nothing but the bus.
+	if n := asked.Load(); n != 0 {
+		t.Errorf("discovery asked a roster or a module's tools %d time(s); it asks the bus", n)
+	}
+
+	// Described without `node`: the address carries the machine.
+	described, isErr := call(t, endpoint, "mesh_describe", map[string]any{"address": "desk/beta.three"})
+	if isErr || strings.Contains(described, `"node"`) || !strings.Contains(described, `"address": "desk/beta.three"`) {
+		t.Errorf("describe: %s", described)
+	}
+	// Its schema, which discovery no longer carries for a module's tool, asked of the runtime serving it.
+	if !strings.Contains(described, `"verbose"`) {
+		t.Errorf("describe lost the tool's arguments: %s", described)
+	}
+
+	// Search finds across the layers; a module that starts serving after the first answer is found.
+	if got, _ := call(t, endpoint, "mesh_search", map[string]any{"query": "shelf"}); !strings.Contains(got, "desk/node-shelf.list") {
+		t.Errorf("search a node seat: %s", got)
+	}
+	if got, _ := call(t, endpoint, "mesh_search", map[string]any{"query": "gamma"}); strings.Contains(got, "gamma.given") {
+		t.Fatalf("gamma was found before it served: %s", got)
+	}
+	mesh.Issue(t, mt.MembershipOf("gamma", "desk", false, nil))
+	gammaOn.Store(`["desk"]`)
+	late := connect(t, "node-tools", "desk")
+	stopLate, err := runtime.Run(late, []runtime.Served{{Module: "gamma", Entrypoints: []string{mt.Fixture("env-gamma.serve.mjs")}}},
+		nil, (&mt.Logs{}).Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stopLate()
+	var found string
+	for i := 0; i < 30; i++ {
+		found, _ = call(t, endpoint, "mesh_search", map[string]any{"query": "gamma given"})
+		if strings.Contains(found, "desk/gamma.given") {
+			break
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	if !strings.Contains(found, "desk/gamma.given") {
+		t.Errorf("a module that arrived later was not found: %s", found)
+	}
+
+	// Only describing a module's tool asks its runtime — once, for the schema discovery no longer carries
+	// (2026-10-04: every tool's schema made a machine's discovery answer outgrow the bus).
+	if n := asked.Load(); n != 1 {
+		t.Errorf("asked a module's tools %d time(s); describing one tool asks once, and discovery never", n)
+	}
+
+	// The old names still answer, unannounced.
+	if got, isErr := call(t, endpoint, "alpha.one", nil); isErr || !strings.Contains(got, `"alpha": 1`) {
+		t.Errorf("an old name: %s", got)
+	}
+}
+
+func TestTheControllersRecordsAreReadAsJSON(t *testing.T) {
+	if got := jsonIn("a warning printed first\n[{\"name\":\"ace\"}]"); got != `[{"name":"ace"}]` {
+		t.Errorf("an array after a warning: %q", got)
+	}
+	if got := jsonIn(`{"seats":[]}`); got != `{"seats":[]}` {
+		t.Errorf("an object: %q", got)
+	}
+}

node-tools/internal/console/client.go

@@ -0,0 +1,155 @@
+package console
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// Tool is a tool as its module — or, for a role's tool, the mesh's records — describes it.
+type Tool struct {
+	Module      string
+	Name        string
+	Description string
+	Input       json.RawMessage
+	Seat        bool
+	Scope       string
+	Subjects    []string
+}
+
+// Listing is what the mesh could say about its tools; silence is named, never dropped (design 34 §3).
+type Listing struct {
+	Tools        []Tool
+	NotAnswering []string
+}
+
+// Seats is the seats and their verbs, so `<seat>.<verb>` resolves to the role.
+type Seats map[string]map[string]bool
+
+func seatsIn(l *Listing) Seats {
+	out := Seats{}
+	for _, t := range l.Tools {
+		if !t.Seat {
+			continue
+		}
+		if out[t.Module] == nil {
+			out[t.Module] = map[string]bool{}
+		}
+		out[t.Module][t.Name] = true
+	}
+	return out
+}
+
+// toolKey is the key a call uses: a role's when the prefix is a seat declaring that verb.
+func toolKey(name string, seats Seats) string {
+	if strings.HasPrefix(name, "seat:") {
+		return name
+	}
+	dot := strings.Index(name, ".")
+	if dot < 0 {
+		return name
+	}
+	if seats[name[:dot]][name[dot+1:]] {
+		return "seat:" + name
+	}
+	return name
+}
+
+// toolsOn is the flat catalogue (MESH_CONSOLE_FLAT=1): what announced itself on the bus, every
+// tool and seat verb, and the assignments with tools that did not (novox/hq ADR 0197).
+func toolsOn(conn *bus.Conn) (*Listing, error) {
+	x, err := indexOn(conn, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	return x.Listing, nil
+}
+
+// callTool calls `<module>.<tool>[@<node>]`, on the subject the listing names for it when it names one.
+func callTool(conn *bus.Conn, key string, args any, seats Seats, l *Listing) (bus.Answered, error) {
+	name, node, _ := strings.Cut(key, "@")
+	if !strings.Contains(name, ".") {
+		return bus.Answered{}, fmt.Errorf("%q does not name a tool: write <module>.<tool>, as `mesh tools` lists "+
+			"them, or <module>.<tool>@<node> for the instance on one machine", key)
+	}
+	resolved := toolKey(name, seats)
+	if node != "" {
+		resolved += "@" + node
+	}
+	return conn.Ask(resolved, args, subjectListed(name, node, l))
+}
+
+func subjectListed(name, node string, l *Listing) string {
+	if l == nil {
+		return ""
+	}
+	dot := strings.Index(name, ".")
+	module, tool := name[:dot], name[dot+1:]
+	for _, t := range l.Tools {
+		if t.Module == module && t.Name == tool && !t.Seat {
+			if len(t.Subjects) == 0 {
+				return ""
+			}
+			if node == "" {
+				return t.Subjects[0]
+			}
+			for _, s := range t.Subjects {
+				if strings.HasSuffix(s, "."+node) {
+					return s
+				}
+			}
+			return ""
+		}
+	}
+	return ""
+}
+
+var (
+	noResponders = regexp.MustCompile(`(?i)no responders|503`)
+	// The bus's own two refusals, by their whole phrase. "authorization" alone also matched a tool's own
+	// answer that merely mentions the word — the runtime refusing a state value with an Authorization
+	// header (novox/hq ADR 0201) read as "this account may not call", which sent the reader the wrong way.
+	refused  = regexp.MustCompile(`(?i)permissions violation|authorization violation`)
+	timedOut = regexp.MustCompile(`(?i)timeout`)
+)
+
+// controllerSeat is the seat whose holder keeps what came of every call (novox/hq issue 265).
+const controllerSeat = "mesh-controller"
+
+// whyItFailed says why a call failed, so the remedy is in the words.
+func whyItFailed(key string, err error) string {
+	if err == nil {
+		err = errors.New("failed")
+	}
+	msg := err.Error()
+	switch {
+	case noResponders.MatchString(msg):
+		extra := ""
+		if strings.HasPrefix(key, "seat:") {
+			extra = ", or nothing holds that seat"
+		}
+		return "nothing serves " + key + ". The module may not be assigned to any machine, or it is down" +
+			extra + " — `mesh tools` lists what answered."
+	case refused.MatchString(msg):
+		return "this account may not call " + key + ". What it may call was fixed when it was issued — a " +
+			"person's by `operator issue`, the console's by its manifest."
+	case timedOut.MatchString(msg):
+		// **A timeout is not a failure** (novox/hq issue 265). Something took the call, so it may
+		// still be running and may already have done what was asked: a push said this while it pushed.
+		said := key + " did not answer within " + bus.RequestTimeout.String() + ". That is not a failure: " +
+			"something is serving it, so it may still be running and may already have done what was " +
+			"asked — check before repeating a call that changes the mesh."
+		if strings.HasPrefix(strings.TrimPrefix(key, "seat:"), controllerSeat+".") {
+			// The controller answers every call within seconds, with an id while it runs, so silence
+			// from it is an answer lost on the way — which it keeps.
+			said += " The controller answers every call within seconds, so its answer was lost on the " +
+				"way; " + controllerSeat + ".calls lists its recent calls and what came of each."
+		}
+		return said
+	}
+	return key + " failed: " + msg
+}

node-tools/internal/console/console_test.go

@@ -0,0 +1,131 @@
+package console
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+	"github.com/novox/mesh-tools/node-tools/internal/runtime"
+)
+
+func connect(t *testing.T, module, node string) *bus.Conn {
+	t.Helper()
+	c, err := bus.Connect(bus.Credential{URL: mt.URL(t), Module: module, Node: node})
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.Logf = func(string, ...any) {}
+	t.Cleanup(c.Close)
+	return c
+}
+
+func post(t *testing.T, endpoint string, body string) map[string]any {
+	t.Helper()
+	res, err := http.Post(endpoint, "application/json", bytes.NewBufferString(body))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer res.Body.Close()
+	raw, _ := io.ReadAll(res.Body)
+	var out map[string]any
+	if err := json.Unmarshal(raw, &out); err != nil {
+		t.Fatalf("%d %s", res.StatusCode, raw)
+	}
+	return out
+}
+
+// As node-tools, the runtime serves the bundles and is the console on loopback: the listing is what
+// the modules and the mesh's records answered, and a call reaches the module on the machine named.
+func TestTheConsoleListsAndCallsOverHTTP(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("alpha", "desk", true, nil))
+	mesh.Issue(t, mt.MembershipOf("beta", "desk", false, map[string][]string{"node-shelf": {"list", "clear"}}))
+	nodeTools := connect(t, "node-tools", "desk")
+	stop, err := runtime.Run(nodeTools, []runtime.Served{
+		{Module: "alpha", Entrypoints: []string{mt.Fixture("many-alpha.serve.mjs")}},
+		{Module: "beta", Entrypoints: []string{mt.Fixture("many-beta.serve.mjs")}},
+	}, nil, (&mt.Logs{}).Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+
+	// The controller's records (ADR 0197): ghost declares tools on desk and nothing announces it.
+	controller := connect(t, "mesh-controller", "")
+	stopSeat, _ := controller.HandleSubject("mesh.seat.mesh-controller.tool.modules", func(json.RawMessage) (any, error) {
+		return map[string]any{"ok": true, "output": `[{"module":"alpha","on":["desk"],"tools":true},` +
+			`{"module":"beta","on":["desk"],"tools":true},{"module":"ghost","on":["desk"],"tools":true}]`}, nil
+	})
+	defer stopSeat()
+	controller.Flush()
+
+	flat := NewSurface(nodeTools, "desk.node-tools")
+	flat.Flat = true // the whole catalogue, as before ADR 0195: still reachable, no longer announced
+	up, err := Serve(flat, "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer up.Close()
+	endpoint := "http://" + up.Address + "/mcp"
+
+	init := post(t, endpoint, `{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-03-26","capabilities":{}}}`)
+	if !strings.Contains(init["result"].(map[string]any)["instructions"].(string), "reached as desk.node-tools") {
+		t.Errorf("initialize: %v", init)
+	}
+	listed := post(t, endpoint, `{"jsonrpc":"2.0","id":2,"method":"tools/list"}`)["result"].(map[string]any)
+	var names []string
+	for _, x := range listed["tools"].([]any) {
+		names = append(names, x.(map[string]any)["name"].(string))
+	}
+	if got := strings.Join(names, ","); got != "alpha.one,alpha.two,beta.five,beta.four,beta.three,node-shelf.clear,node-shelf.list" {
+		t.Errorf("listed %s", got)
+	}
+	if got := listed["_meta"].(map[string]any)["notAnswering"]; len(got.([]any)) != 1 || got.([]any)[0] != "ghost on desk" {
+		t.Errorf("not answering: %v", got)
+	}
+	for _, x := range listed["tools"].([]any) {
+		tool := x.(map[string]any)
+		if tool["name"] == "node-shelf.list" {
+			schema := tool["inputSchema"].(map[string]any)
+			if req, _ := schema["required"].([]any); len(req) != 1 || req[0] != "node" {
+				t.Errorf("a node seat's verb does not require node: %v", schema)
+			}
+		}
+	}
+
+	called := post(t, endpoint, `{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"alpha.one","arguments":{"node":"desk"}}}`)
+	content := called["result"].(map[string]any)["content"].([]any)
+	var got map[string]any
+	_ = json.Unmarshal([]byte(content[0].(map[string]any)["text"].(string)), &got)
+	if got["alpha"] != float64(1) || content[1].(map[string]any)["text"] != "answered by desk" {
+		t.Errorf("called: %v", called)
+	}
+	seat := post(t, endpoint, `{"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"node-shelf.list","arguments":{"node":"desk"}}}`)
+	if text := seat["result"].(map[string]any)["content"].([]any)[0].(map[string]any)["text"].(string); !strings.Contains(text, `"a"`) {
+		t.Errorf("seat verb: %v", seat)
+	}
+	refused := post(t, endpoint, `{"jsonrpc":"2.0","id":5,"method":"tools/call","params":{"name":"node-shelf.list","arguments":{}}}`)
+	if refused["error"] == nil {
+		t.Errorf("a node seat's verb was called without its machine: %v", refused)
+	}
+	absent := post(t, endpoint, `{"jsonrpc":"2.0","id":6,"method":"tools/call","params":{"name":"ghost.boo","arguments":{}}}`)
+	result := absent["result"].(map[string]any)
+	if result["isError"] != true || !strings.Contains(result["content"].([]any)[0].(map[string]any)["text"].(string), "nothing serves ghost.boo") {
+		t.Errorf("an absent tool: %v", absent)
+	}
+	res, err := http.Post(endpoint, "application/json", strings.NewReader(`{"jsonrpc":"2.0","method":"notifications/initialized"}`))
+	if err != nil || res.StatusCode != 202 {
+		t.Errorf("a notification: %v %v", res, err)
+	}
+}
+
+func TestTheConsoleListensOnLoopbackAndNowhereElse(t *testing.T) {
+	if _, err := Serve(NewSurface(nil, "x"), "0.0.0.0:0"); err == nil || !strings.Contains(err.Error(), "loopback and nowhere else") {
+		t.Errorf("a non-loopback console was not refused: %v", err)
+	}
+}

node-tools/internal/console/empty_round_test.go

@@ -0,0 +1,151 @@
+package console
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// novox/hq issue 554, reproduced: the laptop's console heard every runtime, then a round in which
+// nothing answered discovery in time — and every seat and module call was refused ("it answered
+// discovery 2s ago, not now") for the five seconds that round was kept, again and again. Now a call
+// is resolved against what the runtime announced last, says how old that is, and reaches the tool; the
+// empty round is logged once, is not kept, and the next question asks again.
+func TestACallAfterARoundThatHeardNothingUsesWhatWasHeardBefore(t *testing.T) {
+	keptWas, patienceWas := IndexKept, announce.Patience
+	IndexKept, announce.Patience = 0, 1200*time.Millisecond
+	t.Cleanup(func() { IndexKept, announce.Patience = keptWas, patienceWas })
+	mt.New(t)
+
+	// The tools answer on their own connection; discovery is answered on another, which goes quiet.
+	tools := connect(t, "node-tools", "laptop")
+	stopTool, err := tools.HandleSubject("mesh.mod.slack.tool.slack_check.laptop", func(json.RawMessage) (any, error) {
+		return map[string]any{"ok": true}, nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopTool)
+	stopSeat, err := tools.HandleSubject("mesh.seat.issue-tracker.tool.list", func(json.RawMessage) (any, error) {
+		return map[string]any{"issues": []int{554}}, nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopSeat)
+	tools.Flush()
+	endpoints := []announce.Endpoint{
+		{Kind: announce.KindTool, Module: "slack", Tool: "slack_check", Node: "laptop", Subject: "mesh.mod.slack.tool.slack_check.laptop"},
+		{Kind: announce.KindSeat, Module: "issue-tracker", Seat: "issue-tracker", Tool: "list", Scope: "mesh", Node: "laptop",
+			Schema: json.RawMessage(`{}`), Subject: "mesh.seat.issue-tracker.tool.list"},
+	}
+	announcing := connect(t, "node-tools", "laptop")
+	stopAnnounce, err := announce.Serve(announcing, announce.Service{Name: "node-tools", ID: "laptop",
+		Metadata: map[string]string{"node": "laptop"}}, func() []announce.Endpoint { return endpoints })
+	if err != nil {
+		t.Fatal(err)
+	}
+	announcing.Flush()
+
+	console := connect(t, "node-tools", "laptop-console")
+	var mu sync.Mutex
+	var logged []string
+	console.Logf = func(f string, a ...any) {
+		mu.Lock()
+		defer mu.Unlock()
+		logged = append(logged, fmt.Sprintf(f, a...))
+	}
+	said := func(words string) int {
+		mu.Lock()
+		defer mu.Unlock()
+		n := 0
+		for _, l := range logged {
+			if strings.Contains(l, words) {
+				n++
+			}
+		}
+		return n
+	}
+	surface := NewSurface(console, "laptop.node-tools")
+	up, err := Serve(surface, "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer up.Close()
+	endpoint := "http://" + up.Address + "/mcp"
+
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "laptop/slack.slack_check"}); isErr || strings.Contains(got, "announced") {
+		t.Fatalf("while discovery hears the runtime: %s", got)
+	}
+
+	// Discovery goes quiet: no PING arrives at all.
+	stopAnnounce()
+	announcing.Flush()
+	for _, address := range []string{"laptop/slack.slack_check", "issue-tracker.list"} {
+		got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": address})
+		if isErr || !strings.Contains(got, "found from what node-tools on laptop announced") ||
+			!strings.Contains(got, "ago: it did not answer the latest round of discovery") {
+			t.Errorf("%s after a round that heard nothing: %s", address, got)
+		}
+	}
+	if got, isErr := call(t, endpoint, "mesh_describe", map[string]any{"address": "issue-tracker.list"}); isErr || !strings.Contains(got, `"found"`) {
+		t.Errorf("describe after a round that heard nothing: %s", got)
+	}
+	if n := said("discovery heard nothing at all"); n != 1 {
+		t.Errorf("the empty round was logged %d time(s), want once: %v", n, logged)
+	}
+	// A runtime really gone: the call is sent on what it announced, and fails with the bus's own refusal,
+	// saying where the address was found.
+	stopTool()
+	tools.Flush()
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "laptop/slack.slack_check"}); !isErr ||
+		!strings.Contains(got, "nothing serves") || !strings.Contains(got, "found from what node-tools on laptop announced") {
+		t.Errorf("a gone runtime's tool: %s", got)
+	}
+	surface.mu.Lock()
+	kept := surface.idx != nil && !surface.idx.Discovery.Empty() && time.Since(surface.idxAt) < time.Second
+	surface.mu.Unlock()
+	if kept {
+		t.Error("a round that heard nothing was kept as the answer")
+	}
+
+	// Discovery answers again: the calls are plain again, and that is logged once.
+	stopAgain, err := announce.Serve(announcing, announce.Service{Name: "node-tools", ID: "laptop",
+		Metadata: map[string]string{"node": "laptop"}}, func() []announce.Endpoint { return endpoints })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopAgain)
+	announcing.Flush()
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "issue-tracker.list"}); isErr || strings.Contains(got, "announced") {
+		t.Errorf("once discovery hears the runtime again: %s", got)
+	}
+	if n := said("discovery hears every runtime again"); n != 1 {
+		t.Errorf("the recovery was logged %d time(s): %v", n, logged)
+	}
+}
+
+// An address known only from an earlier answer says how old it is; one heard fresh on its machine is
+// plain, even where the same module is known only from an earlier answer on another.
+func TestAnAddressKnownOnlyFromAnEarlierAnswerSaysHowOld(t *testing.T) {
+	at := time.Now().Add(-20 * time.Second)
+	x := &index{Modules: map[string]*moduleInfo{"slack": {Module: "slack", On: []string{"laptop"},
+		Tools: []Tool{{Module: "slack", Name: "slack_check"}}}}, Recorded: map[string][]string{},
+		Stale:     map[string]staleFrom{"mod:slack@laptop": {Runtime: "node-tools", Machine: "laptop", At: at}},
+		Discovery: announce.Discovery{Pinged: 0}}
+	got, err := resolve(x, "laptop/slack.slack_check")
+	if err != nil || got.Stale == nil || !strings.Contains(got.Stale.say(), "announced 20s ago") {
+		t.Fatalf("%+v %v", got, err)
+	}
+	// A module heard fresh on one machine and only earlier on another: the fresh one is plain.
+	x.Modules["slack"].On = []string{"desk", "laptop"}
+	if got, err := resolve(x, "desk/slack.slack_check"); err != nil || got.Stale != nil {
+		t.Errorf("a fresh machine's module marked stale: %+v %v", got, err)
+	}
+}

node-tools/internal/console/http.go

@@ -0,0 +1,125 @@
+package console
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/novox/mesh-tools/node-tools/internal/wire"
+)
+
+// bodyLimit is the most a request body may be.
+const bodyLimit = 1 << 20
+
+var loopback = map[string]bool{"127.0.0.1": true, "::1": true, "localhost": true, "[::1]": true}
+
+// Listening is a console that listens: where, with the port the machine gave, and how to stop it.
+type Listening struct {
+	Address string
+	Close   func() error
+}
+
+// Serve listens on host:port, refused unless the host is loopback — said before binding, so a
+// console that would open to a network is a startup failure (ADR 0152).
+func Serve(s *Surface, listen string) (*Listening, error) {
+	at := strings.LastIndex(listen, ":")
+	if at < 0 {
+		return nil, fmt.Errorf("%q is not host:port", listen)
+	}
+	host, portText := listen[:at], listen[at+1:]
+	if !loopback[host] {
+		return nil, fmt.Errorf(`the console listens on loopback and nowhere else (novox/hq ADR 0152): %q is not this `+
+			"machine's own address — whoever is on the machine owns the mesh there, and nobody else may reach this", host)
+	}
+	port, err := strconv.Atoi(portText)
+	if err != nil || port < 0 || port > 65535 {
+		return nil, fmt.Errorf("%q is not a port", portText)
+	}
+	ln, err := net.Listen("tcp", net.JoinHostPort(strings.Trim(host, "[]"), portText))
+	if err != nil {
+		return nil, err
+	}
+	server := &http.Server{Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { route(w, r, s) })}
+	go func() { _ = server.Serve(ln) }()
+	bound := ln.Addr().(*net.TCPAddr).Port
+	return &Listening{Address: host + ":" + strconv.Itoa(bound), Close: func() error { return server.Shutdown(context.Background()) }}, nil
+}
+
+func route(w http.ResponseWriter, r *http.Request, s *Surface) {
+	switch r.URL.Path {
+	case "/":
+		w.Header().Set("content-type", "text/plain; charset=utf-8")
+		_, _ = io.WriteString(w, "the mesh's console: MCP over HTTP at POST /mcp (novox/hq design 34)\n")
+		return
+	case "/mcp":
+	default:
+		writeJSON(w, 404, map[string]any{"error": "the console serves /mcp and nothing else"})
+		return
+	}
+	switch r.Method {
+	case http.MethodPost:
+	case http.MethodDelete:
+		w.WriteHeader(204) // no session to end
+		return
+	default:
+		w.Header().Set("allow", "POST, DELETE")
+		w.WriteHeader(405)
+		return
+	}
+	body, err := io.ReadAll(io.LimitReader(r.Body, bodyLimit+1))
+	if err != nil || len(body) > bodyLimit {
+		if err == nil {
+			err = fmt.Errorf("the request is larger than %d bytes", bodyLimit)
+		}
+		writeJSON(w, 413, map[string]any{"jsonrpc": "2.0", "id": nil, "error": map[string]any{"code": -32600, "message": err.Error()}})
+		return
+	}
+	trimmed := strings.TrimSpace(string(body))
+	if strings.HasPrefix(trimmed, "[") {
+		var batch []Request
+		if err := json.Unmarshal(body, &batch); err != nil {
+			writeJSON(w, 400, map[string]any{"jsonrpc": "2.0", "id": nil, "error": map[string]any{"code": -32700, "message": "the body is not JSON"}})
+			return
+		}
+		replies := []*Reply{}
+		for _, req := range batch {
+			if reply := s.Handle(req); reply != nil {
+				replies = append(replies, reply)
+			}
+		}
+		if len(replies) == 0 {
+			w.WriteHeader(202)
+			return
+		}
+		writeJSON(w, 200, replies)
+		return
+	}
+	var req Request
+	if err := json.Unmarshal(body, &req); err != nil {
+		writeJSON(w, 400, map[string]any{"jsonrpc": "2.0", "id": nil, "error": map[string]any{"code": -32700, "message": "the body is not JSON"}})
+		return
+	}
+	reply := s.Handle(req)
+	if reply == nil {
+		w.WriteHeader(202)
+		return
+	}
+	writeJSON(w, 200, reply)
+}
+
+func writeJSON(w http.ResponseWriter, status int, body any) {
+	text, err := wire.Marshal(body)
+	if err != nil {
+		text, _ = json.Marshal(map[string]any{"error": errors.New("unencodable answer").Error()})
+	}
+	w.Header().Set("content-type", "application/json; charset=utf-8")
+	w.Header().Set("content-length", strconv.Itoa(len(text)))
+	w.WriteHeader(status)
+	_, _ = w.Write(text)
+}

node-tools/internal/console/mcp.go

@@ -0,0 +1,331 @@
+// Package console is the mesh's tools as an MCP server on a machine's loopback (novox/hq design 34,
+// ADR 0152, ADR 0175 §6): the Go port of node-tools' http.ts, mcp.ts and client.ts. A thin adapter:
+// every tool listed is one a module answered for, the schema is the module's, the answer the module's.
+package console
+
+import (
+	"encoding/json"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// Protocol is the MCP version spoken to an agent host.
+const Protocol = "2025-03-26"
+
+// ListingKept is how long a fetched tool list is kept before the modules are asked again.
+var ListingKept = 30 * time.Second
+
+// Request is one JSON-RPC message from a host.
+type Request struct {
+	JSONRPC string          `json:"jsonrpc"`
+	ID      json.RawMessage `json:"id,omitempty"`
+	Method  string          `json:"method"`
+	Params  json.RawMessage `json:"params,omitempty"`
+}
+
+// Reply is one JSON-RPC answer.
+type Reply struct {
+	JSONRPC string          `json:"jsonrpc"`
+	ID      json.RawMessage `json:"id"`
+	Result  any             `json:"result,omitempty"`
+	Error   *RPCError       `json:"error,omitempty"`
+}
+
+// RPCError is a protocol-level refusal.
+type RPCError struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+// Surface answers MCP requests over one bus connection, as one account.
+type Surface struct {
+	conn  *bus.Conn
+	who   string
+	mu    sync.Mutex
+	known *Listing
+	at    time.Time
+	idx   *index
+	idxAt time.Time
+	// runtimes is every runtime discovery has heard, as it last heard it (mesh_runtimes).
+	runtimes map[string]*runtimeSeen
+	// roundSaid is what the last round logged was missing, so a round is logged once (novox/hq issue 554).
+	roundSaid string
+	// Flat announces the whole catalogue, as the console did before ADR 0195: for a person reading
+	// it or a client that wants it. Off by default; MESH_CONSOLE_FLAT=1 turns it on.
+	Flat bool
+}
+
+// NewSurface is the surface over a connection, as `who`.
+func NewSurface(conn *bus.Conn, who string) *Surface {
+	return &Surface{conn: conn, who: who, Flat: os.Getenv("MESH_CONSOLE_FLAT") == "1"}
+}
+
+func (s *Surface) listing() (*Listing, error) {
+	s.mu.Lock()
+	if s.known != nil && time.Since(s.at) <= ListingKept {
+		l := s.known
+		s.mu.Unlock()
+		return l, nil
+	}
+	s.mu.Unlock()
+	l, err := toolsOn(s.conn)
+	if err != nil {
+		return nil, err
+	}
+	s.mu.Lock()
+	s.known, s.at = l, time.Now()
+	s.mu.Unlock()
+	return l, nil
+}
+
+func isNotification(id json.RawMessage) bool {
+	t := strings.TrimSpace(string(id))
+	return t == "" || t == "null"
+}
+
+func answer(id json.RawMessage, result any) *Reply {
+	return &Reply{JSONRPC: "2.0", ID: idOrNull(id), Result: result}
+}
+
+func refuse(id json.RawMessage, code int, message string) *Reply {
+	return &Reply{JSONRPC: "2.0", ID: idOrNull(id), Error: &RPCError{Code: code, Message: message}}
+}
+
+func idOrNull(id json.RawMessage) json.RawMessage {
+	if isNotification(id) {
+		return json.RawMessage("null")
+	}
+	return id
+}
+
+// Handle answers one request; nil for a notification, which expects none.
+func (s *Surface) Handle(r Request) *Reply {
+	notification := isNotification(r.ID)
+	switch r.Method {
+	case "initialize":
+		return answer(r.ID, map[string]any{
+			"protocolVersion": Protocol,
+			"capabilities":    map[string]any{"tools": map[string]any{}},
+			"serverInfo":      map[string]any{"name": "mesh", "version": "1"},
+			"instructions":    s.instructions(),
+		})
+	case "notifications/initialized":
+		return nil
+	case "ping":
+		if notification {
+			return nil
+		}
+		return answer(r.ID, map[string]any{})
+	case "tools/list":
+		if !s.Flat {
+			return answer(r.ID, map[string]any{"tools": discovery()})
+		}
+		l, err := s.listing()
+		if err != nil {
+			return refuse(r.ID, -32603, "the mesh's discovery failed: "+err.Error())
+		}
+		tools := make([]map[string]any, 0, len(l.Tools))
+		inputs := map[string]map[string]json.RawMessage{} // module → tool → input, asked once per module
+		for i, t := range l.Tools {
+			if !t.Seat && len(t.Input) == 0 {
+				if inputs[t.Module] == nil {
+					inputs[t.Module] = toolInputs(s.conn, t.Module)
+				}
+				l.Tools[i].Input = inputs[t.Module][t.Name]
+				t = l.Tools[i]
+			}
+			var schema map[string]any
+			switch {
+			case t.Seat && t.Scope != "node":
+				schema = asSchema(t.Input)
+			case t.Seat:
+				schema = withNode(asSchema(t.Input), "the machine whose seat answers; required, the seat is held once per machine", true)
+			default:
+				schema = withNode(asSchema(t.Input), "", false)
+			}
+			description := t.Description
+			if description == "" {
+				description = t.Name + ", served by " + t.Module
+			}
+			tools = append(tools, map[string]any{"name": t.Module + "." + t.Name, "description": description, "inputSchema": schema})
+		}
+		return answer(r.ID, map[string]any{"tools": tools, "_meta": map[string]any{"notAnswering": l.NotAnswering}})
+	case "tools/call":
+		var p struct {
+			Name      string         `json:"name"`
+			Arguments map[string]any `json:"arguments"`
+		}
+		_ = json.Unmarshal(r.Params, &p)
+		if isDiscovery(p.Name) {
+			if p.Arguments == nil {
+				p.Arguments = map[string]any{}
+			}
+			return answer(r.ID, s.discover(p.Name, p.Arguments))
+		}
+		args := map[string]any{}
+		for k, v := range p.Arguments {
+			args[k] = v
+		}
+		l, _ := s.listing()
+		var roles Seats
+		if l != nil {
+			roles = seatsIn(l)
+		}
+		bare, _, _ := strings.Cut(p.Name, "@")
+		isSeatVerb := roles != nil && strings.HasPrefix(toolKey(bare, roles), "seat:")
+		nodeScoped := false
+		if isSeatVerb && l != nil {
+			for _, t := range l.Tools {
+				if t.Seat && t.Scope == "node" && t.Module+"."+t.Name == bare {
+					nodeScoped = true
+				}
+			}
+		}
+		takesNode := !isSeatVerb || nodeScoped
+		node := ""
+		if takesNode {
+			if n, ok := args["node"].(string); ok {
+				node = n
+			}
+			delete(args, "node")
+		}
+		if nodeScoped && node == "" && !strings.Contains(p.Name, "@") {
+			return refuse(r.ID, -32602, p.Name+" is a machine's seat's verb: name the machine with `node`")
+		}
+		name := p.Name
+		if node != "" && !strings.Contains(p.Name, "@") {
+			name = p.Name + "@" + node
+		}
+		got, err := callTool(s.conn, name, args, roles, l)
+		if err != nil {
+			return answer(r.ID, map[string]any{
+				"content": []map[string]any{{"type": "text", "text": whyItFailed(name, err)}},
+				"isError": true,
+			})
+		}
+		content := []map[string]any{{"type": "text", "text": pretty(got.Result)}}
+		if got.Node != "" {
+			content = append(content, map[string]any{"type": "text", "text": "answered by " + got.Node})
+		}
+		return answer(r.ID, map[string]any{"content": content})
+	}
+	if notification {
+		return nil
+	}
+	return refuse(r.ID, -32601, "mesh's MCP surface has no "+r.Method)
+}
+
+// pretty is a module's answer as JSON text, indented as JSON.stringify(result, null, 2) writes it.
+func pretty(raw json.RawMessage) string {
+	if len(raw) == 0 {
+		return "null"
+	}
+	var v any
+	if json.Unmarshal(raw, &v) != nil {
+		return string(raw)
+	}
+	b, err := json.MarshalIndent(v, "", "  ")
+	if err != nil {
+		return string(raw)
+	}
+	return strings.NewReplacer(`<`, "<", `>`, ">", `&`, "&").Replace(string(b))
+}
+
+// asSchema is a module's declared input as a JSON schema: wrapped when it is a bare map of
+// properties, passed through when it is a schema, empty when nothing was declared.
+func asSchema(raw json.RawMessage) map[string]any {
+	var given map[string]any
+	if json.Unmarshal(raw, &given) != nil || given == nil {
+		return map[string]any{"type": "object", "properties": map[string]any{}}
+	}
+	if given["type"] == "object" {
+		return given
+	}
+	if _, has := given["properties"]; has {
+		return given
+	}
+	if len(given) == 0 {
+		return map[string]any{"type": "object", "properties": map[string]any{}}
+	}
+	return map[string]any{"type": "object", "properties": given}
+}
+
+// withNode adds the optional — or, for a node seat, required — `node` argument (ADR 0159).
+func withNode(schema map[string]any, description string, required bool) map[string]any {
+	properties := map[string]any{}
+	if p, ok := schema["properties"].(map[string]any); ok {
+		for k, v := range p {
+			properties[k] = v
+		}
+	}
+	if _, has := properties["node"]; !has {
+		if description == "" {
+			description = "the machine to ask, when this module runs on several; else whichever answers, and the answer says which"
+		}
+		properties["node"] = map[string]any{"type": "string", "description": description}
+	}
+	out := map[string]any{}
+	for k, v := range schema {
+		out[k] = v
+	}
+	out["type"] = "object"
+	out["properties"] = properties
+	if required {
+		have := []any{}
+		if r, ok := schema["required"].([]any); ok {
+			have = r
+		}
+		hasNode := false
+		for _, x := range have {
+			hasNode = hasNode || x == "node"
+		}
+		if !hasNode {
+			have = append(have, "node")
+		}
+		out["required"] = have
+	}
+	return out
+}
+
+// instructions is what an agent host is told about this surface when it connects.
+func (s *Surface) instructions() string {
+	if s.Flat {
+		return "These are the tools of a Novox mesh, reached as " + s.who + ". Every call goes to the module " +
+			"that serves it; what may be called was fixed when this account was issued, so a " +
+			"refusal means the account, not the tool. The list is what the running modules " +
+			"answered, plus every role's tools from the mesh's records — the mesh's own verbs " +
+			"(mesh-controller.status, .push, .assign …) among them; a module that did not answer " +
+			"is named in the list's _meta and can still be called by <module>.<tool>."
+	}
+	return "The tools of a Novox mesh, reached as " + s.who + ", found by address rather than listed " +
+		"whole (novox/hq ADR 0195). mesh_overview shows the mesh's seats and machines; mesh_machine one " +
+		"machine's seats and modules; mesh_search finds a tool by words; mesh_describe gives one tool's " +
+		"arguments; mesh_call calls it; mesh_runtimes says which machines' runtimes answered discovery, how fast " +
+		"and how much — ask it when an address is said to be missing or on another machine. " + grammar + " What may be called was fixed when this account " +
+		"was issued, so a refusal means the account, not the tool."
+}
+
+// toolInputs is every tool's input schema of one module, asked of a runtime that serves it.
+func toolInputs(conn *bus.Conn, module string) map[string]json.RawMessage {
+	out := map[string]json.RawMessage{}
+	got, err := conn.Ask(module+".tools", map[string]any{}, "")
+	if err != nil {
+		return out
+	}
+	var answer struct {
+		Tools []struct {
+			Name  string          `json:"name"`
+			Input json.RawMessage `json:"input"`
+		} `json:"tools"`
+	}
+	if json.Unmarshal(got.Result, &answer) == nil {
+		for _, t := range answer.Tools {
+			out[t.Name] = t.Input
+		}
+	}
+	return out
+}

node-tools/internal/console/node_argument_test.go

@@ -0,0 +1,52 @@
+package console
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+// novox/hq issue 244: `node` is taken out only where the address names the machine. A seat held once
+// for the mesh takes the machine it acts on as `node`, and is described and called with it — on
+// 2026-10-05 the controller's push was described as taking nothing, and a push naming one machine
+// ran as a push of every machine behind.
+func TestAMeshSeatsNodeIsItsOwnArgument(t *testing.T) {
+	push := Tool{Module: "mesh-controller", Name: "push", Seat: true, Scope: "mesh",
+		Input: json.RawMessage(`{"type":"object","properties":{"node":{"type":"string"},"behind":{"type":"string"}}}`)}
+	mesh := target{Address: "mesh-controller.push", Tool: push, Seat: true}
+
+	props := schemaAsPassed(mesh)["properties"].(map[string]any)
+	if _, has := props["node"]; !has {
+		t.Fatalf("a mesh seat's verb was described without its node: %v", props)
+	}
+	sent, err := argumentsAsSent(mesh, map[string]any{"node": "g1"})
+	if err != nil || sent["node"] != "g1" {
+		t.Fatalf("a mesh seat's verb was called without the machine it was given: %v %v", sent, err)
+	}
+
+	// An argument the seat's verb does not declare is refused, naming it, never sent to be dropped.
+	if _, err := argumentsAsSent(mesh, map[string]any{"machine": "g1"}); err == nil || !strings.Contains(err.Error(), "machine") {
+		t.Fatalf("an undeclared argument was sent: %v", err)
+	}
+
+	// A machine's seat: the address names the machine, so `node` is out of the schema; given the same
+	// machine again it is taken out, given another it is refused.
+	shelf := Tool{Module: "node-shelf", Name: "list", Seat: true, Scope: "node",
+		Input: json.RawMessage(`{"type":"object","properties":{"limit":{"type":"string"}}}`)}
+	onDesk := target{Address: "desk/node-shelf.list", Node: "desk", Tool: shelf, Seat: true}
+	if _, has := schemaAsPassed(onDesk)["properties"].(map[string]any)["node"]; has {
+		t.Fatal("a machine's seat was described with a node the address already names")
+	}
+	if sent, err := argumentsAsSent(onDesk, map[string]any{"node": "desk", "limit": "3"}); err != nil || sent["node"] != nil || sent["limit"] != "3" {
+		t.Fatalf("the same machine named twice: %v %v", sent, err)
+	}
+	if _, err := argumentsAsSent(onDesk, map[string]any{"node": "bench"}); err == nil || !strings.Contains(err.Error(), "bench") {
+		t.Fatalf("another machine in the arguments than in the address was dropped: %v", err)
+	}
+
+	// A module's tool is its own: what it takes beyond node is the module's to judge.
+	beta := target{Address: "desk/beta.three", Node: "desk", Tool: Tool{Module: "beta", Name: "three"}}
+	if sent, err := argumentsAsSent(beta, map[string]any{"node": "desk", "verbose": true}); err != nil || sent["verbose"] != true || sent["node"] != nil {
+		t.Fatalf("a module's tool: %v %v", sent, err)
+	}
+}

node-tools/internal/console/one_name_test.go

@@ -0,0 +1,57 @@
+package console
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+)
+
+// **Issue 287**: mesh-delivery is the delivery's seat, held once for the mesh, and the module holding it,
+// which answers the seat's verbs with tools of the same names and has tools of its own. Discovery put the
+// module's tool and the seat's verb under one key, so the seat was listed with no verb; and every address
+// with the name resolved to the seat — `mesh-delivery.deliveries` and `novox/mesh-delivery.delivery_status`
+// alike were refused, the seat's verbs and the module's tools both out of reach.
+func TestASeatAndAModuleOfOneNameAreEachReached(t *testing.T) {
+	var endpoints []announce.Endpoint
+	for _, tool := range []string{"deliveries", "delivery_status"} {
+		endpoints = append(endpoints, announce.Endpoint{Kind: announce.KindTool, Module: "mesh-delivery", Tool: tool,
+			Node: "anchor", Subject: "mesh.mod.mesh-delivery.tool." + tool + ".anchor"})
+	}
+	for _, verb := range []string{"deliveries", "stalled"} {
+		endpoints = append(endpoints, announce.Endpoint{Kind: announce.KindSeat, Module: "mesh-delivery", Seat: "mesh-delivery",
+			Tool: verb, Scope: "mesh", Subject: "mesh.seat.mesh-delivery.tool." + verb})
+	}
+	x, _, _ := indexOfEndpoints(endpoints)
+
+	s := x.seat("mesh-delivery")
+	if s == nil || len(s.Verbs) != 2 {
+		t.Fatalf("the seat is listed with verbs %v, not its two", s)
+	}
+	if m := x.Modules["mesh-delivery"]; m == nil || len(m.Tools) != 2 {
+		t.Fatalf("the module is listed with tools %v, not its two", m)
+	}
+
+	for address, want := range map[string]struct {
+		seat bool
+		key  string
+	}{
+		"mesh-delivery.deliveries":             {true, "seat:mesh-delivery.deliveries"},
+		"mesh-delivery.stalled":                {true, "seat:mesh-delivery.stalled"},
+		"anchor/mesh-delivery.delivery_status": {false, "mesh-delivery.delivery_status@anchor"},
+		"anchor/mesh-delivery.deliveries":      {false, "mesh-delivery.deliveries@anchor"},
+	} {
+		got, err := resolve(x, address)
+		if err != nil {
+			t.Errorf("%s: %v", address, err)
+			continue
+		}
+		if got.Seat != want.seat || got.Key != want.key {
+			t.Errorf("%s resolves to %+v, not the %s", address, got, want.key)
+		}
+	}
+	// A module tool of the name without a machine: the module keeps state on its machine, so it says so.
+	if _, err := resolve(x, "mesh-delivery.delivery_status"); err == nil || !strings.Contains(err.Error(), "<node>/") {
+		t.Errorf("the module's tool without a machine: %v", err)
+	}
+}

node-tools/internal/console/refusal_test.go

@@ -0,0 +1,37 @@
+package console
+
+import (
+	"errors"
+	"strings"
+	"testing"
+)
+
+// A refusal is said only for the bus's own refusals; a tool's answer that mentions authorization is the
+// tool's answer, not the account's.
+func TestARefusalIsSaidOnlyForTheBussOwn(t *testing.T) {
+	for msg, refusal := range map[string]bool{
+		`nats: Permissions Violation for Publish to "mesh.mod.x.tool.y"`:                        true,
+		"nats: Authorization Violation":                                                         true,
+		`claude-code's servers.all.x carries a field "Authorization", which names a credential`: false,
+	} {
+		got := strings.HasPrefix(whyItFailed("x.y", errors.New(msg)), "this account may not call")
+		if got != refusal {
+			t.Errorf("%q read as a refusal: %v, want %v", msg, got, refusal)
+		}
+	}
+}
+
+// **A timeout says it is not a failure** (novox/hq issue 265): a push that outlasted the wait had
+// pushed, and the caller read "did not answer in time". And from the controller, where its answer is.
+func TestATimeoutIsNotAFailure(t *testing.T) {
+	got := whyItFailed("seat:mesh-controller.push", errors.New("timeout"))
+	for _, want := range []string{"not a failure", "may already have done", "mesh-controller.calls"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("a controller timeout does not say %q: %s", want, got)
+		}
+	}
+	if other := whyItFailed("novox/postgres.postgres_list_databases", errors.New("timeout")); !strings.Contains(other, "not a failure") ||
+		strings.Contains(other, "calls") {
+		t.Errorf("a module's timeout: %s", other)
+	}
+}

node-tools/internal/console/runtimes.go

@@ -0,0 +1,322 @@
+package console
+
+// What discovery heard from each runtime (2026-10-05): the console said a module ran nowhere when the
+// largest runtime's answer arrived after the window closed, and nothing showed that it had. Every
+// round of discovery is remembered per runtime, so a runtime heard before and not now is named, and
+// `mesh_runtimes` says who answered, how fast and how much.
+
+import (
+	"fmt"
+	"log"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+)
+
+// RuntimeForgotten is how long a runtime heard once is expected again: within it, its silence is said
+// wherever an address it might answer is asked for; after it, it is listed only by mesh_runtimes.
+var RuntimeForgotten = 15 * time.Minute
+
+// runtimeSeen is one runtime instance as discovery last heard it.
+type runtimeSeen struct {
+	Name      string
+	ID        string
+	Machine   string
+	LastHeard time.Time
+	Took      time.Duration
+	Bytes     int
+	Modules   int
+	Tools     int
+	SeatVerbs int
+	Shortened string
+	Answered  bool   // in the latest round
+	Why       string // why not, when it did not
+	// Reused is true when its PING said its announcement was unchanged, so it was not fetched again.
+	Reused bool
+	// Last is its last whole answer: what a round that does not hear it uses instead, and what an
+	// unchanged digest stands for (novox/hq issue 554).
+	Last announce.Heard
+}
+
+func runtimeKey(name, id string) string { return name + "/" + id }
+
+// seenOf is what one answer announced, counted.
+func seenOf(h announce.Heard, at time.Time) *runtimeSeen {
+	modules := map[string]bool{}
+	tools := map[string]bool{}
+	verbs := map[string]bool{}
+	for _, e := range announce.Endpoints(h.Info) {
+		switch e.Kind {
+		case announce.KindTool:
+			modules[e.Module] = true
+			tools[e.Module+"."+e.Tool] = true
+		case announce.KindSeat:
+			verbs[e.Seat+"."+e.Tool] = true
+		}
+	}
+	return &runtimeSeen{Name: h.Info.Name, ID: h.Info.ID, Machine: h.Machine(), LastHeard: at, Took: h.Took,
+		Bytes: h.Bytes, Modules: len(modules), Tools: len(tools), SeatVerbs: len(verbs), Shortened: h.Shortened, Answered: true,
+		Reused: h.Reused, Last: h}
+}
+
+// held is the answer this console holds for an instance at this digest (announce.Known): an instance
+// whose announcement is unchanged is not asked for it again (novox/hq issue 554).
+func (s *Surface) held(name, id, digest string) (announce.Heard, bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	r := s.runtimes[runtimeKey(name, id)]
+	if r == nil || r.Last.Digest == "" || r.Last.Digest != digest || r.Last.Info.Name == "" {
+		return announce.Heard{}, false
+	}
+	h := r.Last
+	h.Took, h.Reused = 0, false
+	return h, true
+}
+
+// before is the last answer of every runtime this round did not hear, heard within RuntimeForgotten
+// and not since restarted under another instance (novox/hq issue 554).
+func (s *Surface) before(d announce.Discovery) []earlier {
+	heard := map[string]bool{}
+	running := map[string]bool{}
+	for _, h := range d.Heard {
+		heard[runtimeKey(h.Info.Name, h.Info.ID)] = true
+		if m := h.Machine(); m != "" {
+			running[h.Info.Name+"@"+m] = true
+		}
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	var out []earlier
+	for k, r := range s.runtimes {
+		if heard[k] || r.Last.Info.Name == "" || r.LastHeard.IsZero() || time.Since(r.LastHeard) > RuntimeForgotten {
+			continue
+		}
+		if r.Machine != "" && running[r.Name+"@"+r.Machine] {
+			continue // restarted: the new instance answered
+		}
+		out = append(out, earlier{Heard: r.Last, At: r.LastHeard})
+	}
+	sort.Slice(out, func(i, j int) bool {
+		return runtimeKey(out[i].Heard.Info.Name, out[i].Heard.Info.ID) < runtimeKey(out[j].Heard.Info.Name, out[j].Heard.Info.ID)
+	})
+	return out
+}
+
+// sayRound logs a round of discovery that did not hear every runtime — once, when what it missed
+// changes, and once when every runtime is heard again — so the next case leaves evidence in the
+// journal (novox/hq issue 554). Called with s.mu held, after remember.
+func (s *Surface) sayRound(x *index) {
+	d := x.Discovery
+	var missed []string
+	for _, u := range x.Unheard {
+		who := u.Runtime
+		if u.Machine != "" {
+			who += " on " + u.Machine
+		}
+		missed = append(missed, who)
+	}
+	sort.Strings(missed)
+	shape := strings.Join(missed, ", ")
+	if d.Empty() {
+		shape = "empty|" + shape
+	}
+	if shape == s.roundSaid {
+		return
+	}
+	s.roundSaid = shape
+	reused := 0
+	for _, h := range d.Heard {
+		if h.Reused {
+			reused++
+		}
+	}
+	logf := log.Printf
+	if s.conn != nil && s.conn.Logf != nil {
+		logf = s.conn.Logf
+	}
+	window := fmt.Sprintf("waited %s (window %s, patience %s)", d.Waited.Round(time.Millisecond), announce.Window, announce.Patience)
+	held := ""
+	if len(x.Earlier) > 0 {
+		held = fmt.Sprintf("; what %d of them announced earlier is used, with its age", len(x.Earlier))
+	}
+	switch {
+	case d.Empty():
+		logf("[mesh-tools] discovery heard nothing at all: no PING arrived; %s; not heard: %s%s; asking again at the next question",
+			window, orNone(missed), held)
+	case len(missed) > 0:
+		logf("[mesh-tools] discovery did not hear every runtime: %d PING answer(s), %d announcement(s) (%d unchanged, not fetched); %s; not heard: %s%s",
+			d.Pinged, len(d.Heard), reused, window, shape, held)
+	default:
+		logf("[mesh-tools] discovery hears every runtime again: %d PING answer(s), %d announcement(s) (%d unchanged, not fetched); %s",
+			d.Pinged, len(d.Heard), reused, window)
+	}
+}
+
+func orNone(xs []string) string {
+	if len(xs) == 0 {
+		return "none heard before either"
+	}
+	return strings.Join(xs, ", ")
+}
+
+// remember records a round of discovery and adds to the index every runtime heard lately that did not
+// answer this time. Called with s.mu held.
+func (s *Surface) remember(x *index) {
+	if s.runtimes == nil {
+		s.runtimes = map[string]*runtimeSeen{}
+	}
+	at := x.Discovery.At
+	if at.IsZero() {
+		at = time.Now().UTC()
+	}
+	heard := map[string]bool{}
+	for _, h := range x.Discovery.Heard {
+		k := runtimeKey(h.Info.Name, h.Info.ID)
+		seen := seenOf(h, at)
+		if heard[k] {
+			// Two instances under one name and id: both counted, the slower answer's time kept.
+			prev := s.runtimes[k]
+			seen.Modules += prev.Modules
+			seen.Tools += prev.Tools
+			seen.SeatVerbs += prev.SeatVerbs
+			seen.Bytes += prev.Bytes
+			if prev.Took > seen.Took {
+				seen.Took = prev.Took
+			}
+		}
+		heard[k] = true
+		s.runtimes[k] = seen
+	}
+	// A runtime restarted answers under a new instance id: the old one is gone, not silent, and saying
+	// it was missed would hide nothing but cry wolf after every restart.
+	now := map[string]bool{}
+	for k := range heard {
+		now[s.runtimes[k].Name+"@"+s.runtimes[k].Machine] = true
+	}
+	for k, r := range s.runtimes {
+		if !heard[k] && r.Machine != "" && now[r.Name+"@"+r.Machine] {
+			delete(s.runtimes, k)
+		}
+	}
+	silent := map[string]string{}
+	for _, u := range x.Discovery.Silent {
+		silent[runtimeKey(u.Name, u.ID)] = fmt.Sprintf("it answered PING; what it serves did not arrive within %s", announce.Patience)
+	}
+	for k, r := range s.runtimes {
+		if heard[k] {
+			continue
+		}
+		r.Answered = false
+		used := ""
+		if at, ok := x.Earlier[k]; ok {
+			used = fmt.Sprintf("; what it announced %s ago is used", time.Since(at).Round(time.Second))
+		}
+		if why, ok := silent[k]; ok {
+			r.Why = why
+			if used != "" {
+				for i := range x.Unheard {
+					if x.Unheard[i].Runtime == r.Name && x.Unheard[i].Machine == r.Machine && x.Unheard[i].Why == why {
+						x.Unheard[i].Why += used
+					}
+				}
+			}
+			continue // already in the index's unheard
+		}
+		r.Why = "it did not answer this round of discovery"
+		if time.Since(r.LastHeard) <= RuntimeForgotten {
+			x.Unheard = append(x.Unheard, unheard{Runtime: r.Name, Machine: r.Machine,
+				Why: fmt.Sprintf("it answered discovery %s ago, not now%s", time.Since(r.LastHeard).Round(time.Second), used)})
+		}
+	}
+	for _, u := range x.Discovery.Silent {
+		k := runtimeKey(u.Name, u.ID)
+		if _, known := s.runtimes[k]; !known {
+			s.runtimes[k] = &runtimeSeen{Name: u.Name, ID: u.ID, Machine: u.Machine, Why: silent[k]}
+		}
+	}
+}
+
+// runtimesAnswer is mesh_runtimes: discovery asked now, and every runtime as it was heard.
+func (s *Surface) runtimesAnswer() map[string]any {
+	x, err := s.indexAsked(true)
+	if err != nil {
+		return failure("the mesh's discovery failed: " + err.Error())
+	}
+	s.mu.Lock()
+	var all []runtimeSeen
+	for _, r := range s.runtimes {
+		all = append(all, *r)
+	}
+	s.mu.Unlock()
+	sort.Slice(all, func(i, j int) bool {
+		if all[i].Machine != all[j].Machine {
+			return all[i].Machine < all[j].Machine
+		}
+		return runtimeKey(all[i].Name, all[i].ID) < runtimeKey(all[j].Name, all[j].ID)
+	})
+	now := time.Now()
+	var answered, notHeard []map[string]any
+	onMachine := map[string]bool{}
+	for _, r := range all {
+		entry := map[string]any{"runtime": r.Name, "instance": r.ID}
+		if r.Machine != "" {
+			entry["machine"] = r.Machine
+		}
+		if !r.LastHeard.IsZero() {
+			entry["last heard"] = r.LastHeard.Format(time.RFC3339)
+			entry["last heard, ago"] = now.Sub(r.LastHeard).Round(time.Second).String()
+			entry["took"] = r.Took.Round(time.Millisecond).String()
+			entry["bytes"] = r.Bytes
+			entry["modules"] = r.Modules
+			entry["tools"] = r.Tools
+			entry["seat verbs"] = r.SeatVerbs
+			entry["shortened"] = r.Shortened != ""
+			if r.Shortened != "" {
+				entry["shortened, how"] = r.Shortened
+			}
+			if r.Reused && r.Answered {
+				entry["announcement"] = "unchanged (its PING's digest), so not fetched again; took is its PING's"
+			}
+		}
+		if r.Answered {
+			onMachine[r.Machine] = true
+			answered = append(answered, entry)
+		} else {
+			entry["why"] = r.Why
+			if r.LastHeard.IsZero() {
+				entry["last heard"] = "never in full, since this console started"
+			}
+			notHeard = append(notHeard, entry)
+		}
+	}
+	for _, m := range x.Machines {
+		if !onMachine[m] && !machineListed(notHeard, m) {
+			notHeard = append(notHeard, map[string]any{"machine": m,
+				"why": "the mesh knows this machine and no runtime on it has answered discovery since this console started"})
+		}
+	}
+	if answered == nil {
+		answered = []map[string]any{}
+	}
+	if notHeard == nil {
+		notHeard = []map[string]any{}
+	}
+	return answerText(map[string]any{
+		"asked":     x.Discovery.At.Format(time.RFC3339),
+		"waited":    x.Discovery.Waited.Round(time.Millisecond).String(),
+		"window":    fmt.Sprintf("at least %s; up to %s for a runtime that answered PING, or until one does", announce.Window, announce.Patience),
+		"answered":  answered,
+		"not heard": notHeard,
+	})
+}
+
+func machineListed(entries []map[string]any, machine string) bool {
+	for _, e := range entries {
+		if e["machine"] == machine {
+			return true
+		}
+	}
+	return false
+}

node-tools/internal/console/runtimes_test.go

@@ -0,0 +1,223 @@
+package console
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go/micro"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// slowRuntime answers PING at once and INFO after `lag`, or never with a negative lag.
+func slowRuntime(t *testing.T, conn *bus.Conn, node string, lag time.Duration, endpoints []announce.Endpoint) {
+	t.Helper()
+	id := micro.ServiceIdentity{Name: "node-tools", ID: node, Version: announce.Version, Metadata: map[string]string{"node": node}}
+	ping, _ := json.Marshal(micro.Ping{ServiceIdentity: id, Type: micro.PingResponseType})
+	stop, err := conn.Raw("$SRV.PING", func(string, []byte) []byte { return ping })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	// Asked of every service, and of this instance by name and id — as discovery asks it (issue 554).
+	info := func(string, []byte) []byte {
+		if lag < 0 {
+			return nil
+		}
+		time.Sleep(lag)
+		body, _ := json.Marshal(announce.Info(announce.Service{Name: id.Name, ID: id.ID, Metadata: id.Metadata}, endpoints))
+		return body
+	}
+	for _, subject := range []string{"$SRV.INFO", "$SRV.INFO." + id.Name + "." + id.ID} {
+		stop, err := conn.Raw(subject, info)
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+	conn.Flush()
+}
+
+// The laptop's symptom (2026-10-05), reproduced: its runtime's one large answer reached the console
+// after the 750 ms window, and the console said its modules ran nowhere — "nothing in the mesh is
+// called slack" — or ran only on another machine. Now a runtime that said it is there is waited for,
+// one that never says what it serves is named wherever an address it might answer is asked for, and
+// mesh_runtimes shows who answered, how fast and how much.
+func TestARuntimeThatAnswersLateIsFoundAndOneThatNeverDoesIsNamed(t *testing.T) {
+	keptWas, patienceWas := IndexKept, announce.Patience
+	// Kept for the test: one round of discovery answers every question but mesh_runtimes, which asks anew.
+	IndexKept, announce.Patience = time.Minute, 2500*time.Millisecond
+	t.Cleanup(func() { IndexKept, announce.Patience = keptWas, patienceWas })
+	mt.New(t)
+
+	laptop := connect(t, "node-tools", "laptop")
+	stopTool, err := laptop.HandleSubject("mesh.mod.slack.tool.slack_check.laptop", func(json.RawMessage) (any, error) {
+		return map[string]any{"ok": true}, nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopTool)
+	slowRuntime(t, laptop, "laptop", announce.Window+400*time.Millisecond, []announce.Endpoint{
+		{Kind: announce.KindTool, Module: "slack", Tool: "slack_check", Node: "laptop", Description: "Is Slack started once?",
+			Subject: "mesh.mod.slack.tool.slack_check.laptop"},
+		{Kind: announce.KindTool, Module: "nextcloud-client", Tool: "nextcloud_check", Node: "laptop",
+			Subject: "mesh.mod.nextcloud-client.tool.nextcloud_check.laptop"},
+	})
+	sleeper := connect(t, "node-tools", "sleeper")
+	slowRuntime(t, sleeper, "sleeper", -1, nil)
+	desktop := connect(t, "node-tools", "desktop")
+	slowRuntime(t, desktop, "desktop", 0, []announce.Endpoint{
+		{Kind: announce.KindTool, Module: "nextcloud-client", Tool: "nextcloud_check", Node: "desktop",
+			Subject: "mesh.mod.nextcloud-client.tool.nextcloud_check.desktop"},
+	})
+
+	controller := connect(t, "mesh-controller", "bench")
+	for verb, output := range map[string]string{
+		"nodes": `[{"name":"laptop"},{"name":"sleeper"},{"name":"desktop"},{"name":"bench"}]`,
+		"modules": `[{"module":"slack","on":["laptop"],"tools":true},{"module":"nap","on":["sleeper"],"tools":true},` +
+			`{"module":"nextcloud-client","on":["laptop","desktop","sleeper"],"tools":true}]`,
+	} {
+		output := output
+		stop, err := controller.HandleSubject("mesh.seat.mesh-controller.tool."+verb, func(json.RawMessage) (any, error) {
+			return map[string]any{"output": output, "ok": true}, nil
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
+	controller.Flush()
+
+	console := connect(t, "node-tools", "laptop-console")
+	up, err := Serve(NewSurface(console, "laptop.node-tools"), "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer up.Close()
+	endpoint := "http://" + up.Address + "/mcp"
+
+	// The late answer is waited for: the laptop's module is found and called.
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "laptop/slack.slack_check"}); isErr || !strings.Contains(got, `"ok": true`) {
+		t.Errorf("a late runtime's module: %s", got)
+	}
+	if got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": "laptop/nextcloud-client.nextcloud_check"}); isErr && strings.Contains(got, "does not run on laptop") {
+		t.Errorf("a late runtime's module was said to run elsewhere: %s", got)
+	}
+	machine, _ := call(t, endpoint, "mesh_machine", map[string]any{"node": "laptop"})
+	if !strings.Contains(machine, "laptop/slack.slack_check") {
+		t.Errorf("the late runtime's machine lists nothing: %s", machine)
+	}
+
+	// The silent one is named, never called missing.
+	for address, want := range map[string]string{
+		"sleeper/nap.doze":                         "nap is assigned to sleeper in the mesh's records, but nothing that answered discovery serves it: discovery did not hear in full from node-tools on sleeper (it answered PING",
+		"sleeper/nextcloud-client.nextcloud_check": "nextcloud-client on sleeper did not answer discovery: discovery did not hear in full from node-tools on sleeper",
+	} {
+		got, isErr := call(t, endpoint, "mesh_call", map[string]any{"address": address})
+		if !isErr || !strings.Contains(got, want) || strings.Contains(got, "nothing in the mesh is called") || strings.Contains(got, "does not run on") {
+			t.Errorf("%s: %s\nwant %q", address, got, want)
+		}
+	}
+	machine, _ = call(t, endpoint, "mesh_machine", map[string]any{"node": "sleeper"})
+	if !strings.Contains(machine, `"incomplete"`) || !strings.Contains(machine, `"modules": []`) {
+		t.Errorf("a machine whose runtime did not answer: %s", machine)
+	}
+	overview, _ := call(t, endpoint, "mesh_overview", nil)
+	if !strings.Contains(overview, "the runtime node-tools on sleeper") {
+		t.Errorf("overview does not name the silent runtime: %s", overview)
+	}
+
+	// mesh_runtimes: who answered, how fast, how much; who did not.
+	got, isErr := call(t, endpoint, "mesh_runtimes", nil)
+	if isErr {
+		t.Fatal(got)
+	}
+	var report struct {
+		Answered []map[string]any `json:"answered"`
+		NotHeard []map[string]any `json:"not heard"`
+	}
+	if err := json.Unmarshal([]byte(got), &report); err != nil {
+		t.Fatalf("%v: %s", err, got)
+	}
+	var lap map[string]any
+	for _, r := range report.Answered {
+		if r["machine"] == "laptop" {
+			lap = r
+		}
+	}
+	if lap == nil {
+		t.Fatalf("the laptop's runtime is not listed as answering: %s", got)
+	}
+	took, _ := time.ParseDuration(lap["took"].(string))
+	if took < announce.Window || lap["bytes"].(float64) <= 0 || lap["modules"].(float64) != 2 || lap["tools"].(float64) != 2 ||
+		lap["shortened"] != false || lap["last heard"] == nil {
+		t.Errorf("the laptop's runtime: %v", lap)
+	}
+	if !strings.Contains(got, `"machine": "sleeper"`) || !strings.Contains(got, "answered PING") {
+		t.Errorf("the silent runtime is not listed: %s", got)
+	}
+	silent := false
+	for _, r := range report.NotHeard {
+		silent = silent || r["machine"] == "sleeper"
+	}
+	if !silent {
+		t.Errorf("sleeper is not among the not heard: %s", got)
+	}
+}
+
+// A runtime heard once and silent now is named in the answers about its machine.
+func TestARuntimeHeardBeforeAndNotNowIsNamed(t *testing.T) {
+	s := &Surface{}
+	before := &index{Modules: map[string]*moduleInfo{}, Recorded: map[string][]string{}, Discovery: announce.Discovery{At: time.Now().UTC(),
+		Heard: []announce.Heard{{Info: micro.Info{ServiceIdentity: micro.ServiceIdentity{Name: "node-tools", ID: "laptop",
+			Metadata: map[string]string{"node": "laptop"}}}, Took: 300 * time.Millisecond, Bytes: 1000}}}}
+	s.remember(before)
+	now := &index{Modules: map[string]*moduleInfo{"nextcloud-client": {Module: "nextcloud-client", On: []string{"desktop"},
+		Tools: []Tool{{Module: "nextcloud-client", Name: "nextcloud_check"}}}}, Recorded: map[string][]string{},
+		Discovery: announce.Discovery{At: time.Now().UTC(), Pinged: 1}} // desktop's runtime answered
+	s.remember(now)
+	if len(now.Unheard) != 1 || now.Unheard[0].Machine != "laptop" {
+		t.Fatalf("unheard: %+v", now.Unheard)
+	}
+	_, err := resolve(now, "laptop/nextcloud-client.nextcloud_check")
+	if err == nil || !strings.Contains(err.Error(), "nextcloud-client on laptop did not answer discovery") ||
+		!strings.Contains(err.Error(), "answered discovery") {
+		t.Errorf("%v", err)
+	}
+	_, err = resolve(now, "laptop/slack.slack_check")
+	if err == nil || strings.Contains(err.Error(), "nothing in the mesh is called") || !strings.Contains(err.Error(), "slack may be theirs") {
+		t.Errorf("%v", err)
+	}
+	// Nobody unheard: the plain answers stand.
+	quiet := &index{Modules: now.Modules, Recorded: map[string][]string{}, Discovery: now.Discovery}
+	if _, err := resolve(quiet, "laptop/nextcloud-client.nextcloud_check"); err == nil || !strings.Contains(err.Error(), "does not run on laptop; it runs on desktop") {
+		t.Errorf("%v", err)
+	}
+	if _, err := resolve(quiet, "laptop/slack.slack_check"); err == nil || !strings.Contains(err.Error(), "nothing in the mesh is called slack") {
+		t.Errorf("%v", err)
+	}
+}
+
+// A runtime restarted answers under a new instance id; its old instance is gone, not unheard.
+func TestARestartedRuntimeIsNotNamedUnheard(t *testing.T) {
+	heard := func(id string) *index {
+		return &index{Modules: map[string]*moduleInfo{}, Recorded: map[string][]string{}, Discovery: announce.Discovery{At: time.Now().UTC(),
+			Heard: []announce.Heard{{Info: micro.Info{ServiceIdentity: micro.ServiceIdentity{Name: "node-tools", ID: id,
+				Metadata: map[string]string{"node": "laptop"}}}}}}}
+	}
+	s := &Surface{}
+	s.remember(heard("before-restart"))
+	after := heard("after-restart")
+	s.remember(after)
+	if len(after.Unheard) != 0 {
+		t.Errorf("a restarted runtime was named unheard: %+v", after.Unheard)
+	}
+	if len(s.runtimes) != 1 {
+		t.Errorf("the old instance is still kept: %d runtimes", len(s.runtimes))
+	}
+}

node-tools/internal/console/search.go

@@ -0,0 +1,272 @@
+package console
+
+// Finding a tool by the words an agent already has (novox/hq ADR 0245).
+//
+// An agent that wants a unit's log reaches for `journalctl`, and one that wants a container's for `docker
+// logs`; it searches with those words, or with `logs`. Matched against names and descriptions alone, none
+// of them found the service manager's `journal` — whose description says "journal", never "logs" or
+// "journalctl" — and the agent went round the mesh over ssh. So each verb and tool says what it replaces,
+// and search matches three ways, best first:
+//
+//  1. **The query is a command a tool replaces** — `journalctl -u x`, `systemctl status x`, `docker ps`:
+//     every word of the replaced command, in order, among the query's words. The most specific command wins.
+//  2. **Every word is in the tool's name, its replaced commands or its description**, a word also matching
+//     through a short table of the words agents use for the mesh's (logs ⇄ journal, ps ⇄ list). A word in
+//     the name or a replaced command weighs more than one in the description, and a name the query says
+//     whole more than one it says in part.
+//  3. Nothing else: a search that matches nothing says so.
+//
+// Ties go to a seat — the place tools belong — then to the shorter name, then by address.
+
+import (
+	"encoding/json"
+	"path"
+	"sort"
+	"strings"
+	"unicode"
+)
+
+// synonyms are the words an agent uses for the mesh's own, each matching the other's (a word, not part
+// of one: `log` must not match `login`). Kept short: a command is said by the tool that replaces it.
+var synonyms = map[string][]string{
+	"logs":      {"log", "journal"},
+	"log":       {"logs", "journal"},
+	"journal":   {"logs", "log"},
+	"ps":        {"list", "running"},
+	"ls":        {"list"},
+	"list":      {"ps", "ls"},
+	"restart":   {"restarts"},
+	"service":   {"unit", "units"},
+	"services":  {"unit", "units"},
+	"unit":      {"service"},
+	"container": {"containers", "docker"},
+	"firewall":  {"filter", "nftables"},
+	"hosts":     {"hostname"},
+}
+
+// hit is one match as mesh_search answers it.
+type hit struct {
+	Address string `json:"address"`
+	Does    string `json:"does"`
+	// InsteadOf is the command the query matched, when it matched one the tool replaces.
+	InsteadOf string `json:"instead_of,omitempty"`
+	Also      string `json:"also,omitempty"`
+	score     int
+}
+
+// words are a text's words, lower-cased, split at anything that is not a letter, a digit, `-` or `_`
+// within a word — so `node-service-manager.journal` is its three names' parts and the whole.
+func words(s string) []string {
+	var out []string
+	for _, w := range strings.FieldsFunc(strings.ToLower(s), func(r rune) bool {
+		return !(unicode.IsLetter(r) || unicode.IsDigit(r) || r == '-' || r == '_' || r == '/')
+	}) {
+		out = append(out, w)
+		for _, part := range strings.FieldsFunc(w, func(r rune) bool { return r == '-' || r == '_' || r == '/' }) {
+			if part != w {
+				out = append(out, part)
+			}
+		}
+	}
+	return out
+}
+
+// commandWords are a command line's words as matched against a replaced command: lower-cased, a
+// program named by path reduced to its name, and what only runs it (`sudo`) left out.
+func commandWords(line string) []string {
+	var out []string
+	for i, w := range strings.Fields(strings.ToLower(line)) {
+		if i == 0 || strings.HasPrefix(w, "/") {
+			w = path.Base(w)
+		}
+		if w == "sudo" {
+			continue
+		}
+		out = append(out, w)
+	}
+	return out
+}
+
+// inOrder says whether every one of want is among have, in the same order.
+func inOrder(want, have []string) bool {
+	i := 0
+	for _, h := range have {
+		if i < len(want) && h == want[i] {
+			i++
+		}
+	}
+	return len(want) > 0 && i == len(want)
+}
+
+// replacedBy is the replaced command a query names, the most specific of those it matches, or "".
+func replacedBy(query string, replaces []string) string {
+	q := commandWords(query)
+	best, bestLen := "", 0
+	for _, r := range replaces {
+		w := commandWords(r)
+		if inOrder(w, q) && len(w) > bestLen {
+			best, bestLen = r, len(w)
+		}
+	}
+	return best
+}
+
+// scoreOf is how well a tool matches the query: 0 for not at all.
+func scoreOf(query string, qwords []string, name, description string, replaces []string) (int, string) {
+	if cmd := replacedBy(query, replaces); cmd != "" {
+		return 100 + 10*len(commandWords(cmd)), cmd
+	}
+	strong := strings.ToLower(name + " " + strings.Join(replaces, " "))
+	weak := strings.ToLower(description)
+	strongWords := map[string]bool{}
+	for _, w := range words(strong) {
+		strongWords[w] = true
+	}
+	weakWords := map[string]bool{}
+	for _, w := range words(weak) {
+		weakWords[w] = true
+	}
+	score := 10
+	for _, w := range qwords {
+		switch {
+		case strings.Contains(strong, w):
+			score += 5
+		case strings.Contains(weak, w):
+			score++
+		default:
+			found := 0
+			for _, s := range synonyms[w] {
+				if strongWords[s] {
+					found = 5
+					break
+				}
+				if weakWords[s] {
+					found = 1
+				}
+			}
+			if found == 0 {
+				return 0, ""
+			}
+			score += found
+		}
+	}
+	// A name the query says whole — `docker logs` for docker_logs, not docker_secrets_in_logs — first.
+	own := name[strings.LastIndex(name, ".")+1:]
+	whole := true
+	for _, part := range strings.FieldsFunc(strings.ToLower(own), func(r rune) bool { return r == '_' || r == '-' }) {
+		in := false
+		for _, w := range qwords {
+			in = in || w == part
+		}
+		whole = whole && in
+	}
+	if whole {
+		score += 2
+	}
+	return score, ""
+}
+
+// search is mesh_search's answer: every match, best first.
+func (x *index) search(query string) []hit {
+	query = strings.ToLower(strings.TrimSpace(query))
+	qwords := strings.Fields(query)
+	var hits []hit
+	for _, st := range x.Seats {
+		for _, v := range st.Verbs {
+			replaces := x.Replaces["seat:"+st.Seat+"."+v.Name]
+			score, cmd := scoreOf(query, qwords, st.Seat+"."+v.Name, v.Description, replaces)
+			if score == 0 {
+				continue
+			}
+			h := hit{Does: firstLine(v.Description), InsteadOf: cmd, score: score + 1} // a seat first, on a tie
+			if st.Scope == "node" {
+				on := nodesOf(st.Holders)
+				first := "<node>"
+				if len(on) > 0 {
+					first = on[0]
+					if len(on) > 1 {
+						h.Also = "also on " + strings.Join(on[1:], ", ")
+					}
+				}
+				h.Address = first + "/" + st.Seat + "." + v.Name
+			} else {
+				h.Address = st.Seat + "." + v.Name
+			}
+			hits = append(hits, h)
+		}
+	}
+	names := make([]string, 0, len(x.Modules))
+	for n := range x.Modules {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	for _, n := range names {
+		m := x.Modules[n]
+		for _, t := range m.Tools {
+			score, cmd := scoreOf(query, qwords, m.Module+"."+t.Name, t.Description, x.Replaces[m.Module+"."+t.Name])
+			if score == 0 {
+				continue
+			}
+			h := hit{Does: firstLine(t.Description), InsteadOf: cmd, score: score}
+			switch {
+			case m.Interchangeable:
+				h.Address, h.Also = m.Module+"."+t.Name, "any instance; on "+orNobody(m.On)
+			case len(m.On) == 0:
+				h.Address, h.Also = "<node>/"+m.Module+"."+t.Name, "the mesh places it on no machine"
+			default:
+				h.Address = m.On[0] + "/" + m.Module + "." + t.Name
+				if len(m.On) > 1 {
+					h.Also = "also on " + strings.Join(m.On[1:], ", ")
+				}
+			}
+			hits = append(hits, h)
+		}
+	}
+	// Best first; on a tie the shorter name — the plainer tool — then the address, so an answer never
+	// depends on the order discovery heard things in.
+	sort.SliceStable(hits, func(i, j int) bool {
+		if hits[i].score != hits[j].score {
+			return hits[i].score > hits[j].score
+		}
+		a, b := hits[i].Address[strings.LastIndex(hits[i].Address, ".")+1:], hits[j].Address[strings.LastIndex(hits[j].Address, ".")+1:]
+		if len(a) != len(b) {
+			return len(a) < len(b)
+		}
+		return hits[i].Address < hits[j].Address
+	})
+	return hits
+}
+
+// replacesOf is what every verb and tool replaces, from the controller's records (novox/hq ADR 0245):
+// a seat's verbs from its `tools` answer, keyed `seat:<seat>.<verb>`, and a module's own tools from
+// its `modules` answer, keyed `<module>.<tool>`. A controller older than the field answers neither,
+// and search matches names and descriptions as before.
+func replacesOf(toolsAnswer json.RawMessage, modules []recordedModule) map[string][]string {
+	out := map[string][]string{}
+	var seats struct {
+		Seats []struct {
+			Seat  string `json:"seat"`
+			Tools []struct {
+				Name     string   `json:"name"`
+				Replaces []string `json:"replaces"`
+			} `json:"tools"`
+		} `json:"seats"`
+	}
+	if json.Unmarshal(toolsAnswer, &seats) == nil {
+		for _, s := range seats.Seats {
+			for _, t := range s.Tools {
+				if len(t.Replaces) > 0 {
+					out["seat:"+s.Seat+"."+t.Name] = t.Replaces
+				}
+			}
+		}
+	}
+	for _, m := range modules {
+		for tool, r := range m.Replaces {
+			if len(r) > 0 {
+				out[m.Module+"."+tool] = r
+			}
+		}
+	}
+	return out
+}

node-tools/internal/console/search_test.go

@@ -0,0 +1,151 @@
+package console
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+)
+
+// meshToSearch is a mesh as discovery and the controller's records describe it: the service manager's
+// verbs on two machines, the controller's own, a docker module with its tools, and what each replaces
+// as the records say it — the seats' from `tools`, the module's from `modules`.
+func meshToSearch(t *testing.T) *index {
+	t.Helper()
+	var endpoints []announce.Endpoint
+	verbs := map[string]string{
+		"units":   "The units the service manager knows in a scope, each with its load, active and sub state.",
+		"status":  "One unit as the service manager sees it now: its states, whether it starts at boot.",
+		"restart": "Restart one unit.",
+		"journal": "The last lines of one unit's journal (at most 2000).",
+	}
+	for _, node := range []string{"anchor", "laptop"} {
+		for verb, does := range verbs {
+			endpoints = append(endpoints, announce.Endpoint{Kind: announce.KindSeat, Module: "systemd", Seat: "node-service-manager",
+				Tool: verb, Scope: "node", Node: node, Description: does,
+				Subject: "mesh.seat.node-service-manager.tool." + verb + "." + node})
+		}
+	}
+	for verb, does := range map[string]string{
+		"node":  "What one machine reported it can do, what it is assigned, and why.",
+		"nodes": "Every machine the mesh knows, with whether it is converged or adopted.",
+	} {
+		endpoints = append(endpoints, announce.Endpoint{Kind: announce.KindSeat, Module: "mesh-controller", Seat: "mesh-controller",
+			Tool: verb, Scope: "mesh", Description: does, Subject: "mesh.seat.mesh-controller.tool." + verb})
+	}
+	for tool, does := range map[string]string{
+		"docker_list":            "Every container on this machine: name, image, state, ports.",
+		"docker_logs":            "The last lines a container wrote.",
+		"docker_secrets_in_logs": "Whether a container's logs hold a secret.",
+		"docker_restart":         "Restart one container.",
+	} {
+		endpoints = append(endpoints, announce.Endpoint{Kind: announce.KindTool, Module: "docker", Tool: tool, Node: "anchor",
+			Description: does, Subject: "mesh.mod.docker.tool." + tool + ".anchor"})
+	}
+	x, _, _ := indexOfEndpoints(endpoints)
+	tools := json.RawMessage(`{"seats":[{"seat":"node-service-manager","scope":"node","tools":[
+		{"name":"units","replaces":["systemctl list-units","systemctl --failed"]},
+		{"name":"status","replaces":["systemctl status","systemctl is-active"]},
+		{"name":"restart","replaces":["systemctl restart"]},
+		{"name":"journal","replaces":["journalctl"]}]},
+		{"seat":"mesh-controller","scope":"mesh","tools":[{"name":"node","replaces":["hostnamectl","uptime"]},{"name":"nodes"}]}]}`)
+	x.Replaces = replacesOf(tools, []recordedModule{{Module: "docker", On: []string{"anchor"}, Tools: true,
+		Replaces: map[string][]string{"docker_list": {"docker ps"}, "docker_logs": {"docker logs"}, "docker_restart": {"docker restart"}}}})
+	return x
+}
+
+// **The words an agent has find the verb first** (novox/hq ADR 0245): the command it would have run, or
+// the word it would have used, puts the mesh's tool for it at the top.
+func TestSearchFindsTheToolThatReplacesACommandFirst(t *testing.T) {
+	x := meshToSearch(t)
+	for query, want := range map[string]string{
+		"journalctl":                          "anchor/node-service-manager.journal",
+		"journalctl -u mesh-controller -n 50": "anchor/node-service-manager.journal",
+		"sudo journalctl -fu sshd":            "anchor/node-service-manager.journal",
+		"/usr/bin/journalctl":                 "anchor/node-service-manager.journal",
+		"logs":                                "anchor/node-service-manager.journal",
+		"systemctl status":                    "anchor/node-service-manager.status",
+		"systemctl status nats.service":       "anchor/node-service-manager.status",
+		"systemctl restart mesh-controller":   "anchor/node-service-manager.restart",
+		"systemctl --failed":                  "anchor/node-service-manager.units",
+		"docker ps":                           "anchor/docker.docker_list",
+		"docker ps -a":                        "anchor/docker.docker_list",
+		"docker logs":                         "anchor/docker.docker_logs",
+		"docker logs --tail 100 nats":         "anchor/docker.docker_logs",
+		"docker restart nats":                 "anchor/docker.docker_restart",
+		"container logs":                      "anchor/docker.docker_logs",
+		"uptime":                              "mesh-controller.node",
+	} {
+		hits := x.search(query)
+		if len(hits) == 0 {
+			t.Errorf("%q found nothing; want %s first", query, want)
+			continue
+		}
+		if hits[0].Address != want {
+			var got []string
+			for _, h := range hits {
+				got = append(got, h.Address)
+			}
+			t.Errorf("%q found %s first; want %s (all: %s)", query, hits[0].Address, want, strings.Join(got, ", "))
+		}
+	}
+}
+
+// A match on a replaced command says which command it replaced, and the most specific one wins.
+func TestASearchByCommandSaysWhatItReplaces(t *testing.T) {
+	x := meshToSearch(t)
+	hits := x.search("systemctl status sshd")
+	if hits[0].InsteadOf != "systemctl status" {
+		t.Errorf("the match does not say what it replaces: %+v", hits[0])
+	}
+	if hits[0].Also != "also on laptop" {
+		t.Errorf("a node seat's verb does not say its other machines: %+v", hits[0])
+	}
+	// `logs` also finds the container's logs, after the journal — both are answers.
+	var docker bool
+	for _, h := range x.search("logs")[:3] {
+		docker = docker || h.Address == "anchor/docker.docker_logs"
+	}
+	if !docker {
+		t.Errorf("`logs` does not find docker_logs among the first: %+v", x.search("logs"))
+	}
+}
+
+// What search did before stays: every word in a name or description, and nothing for a word nothing has.
+// A synonym is a word, never part of one: `logs` matches through `log`, and finds no `login`.
+func TestSearchStillMatchesEveryWord(t *testing.T) {
+	x := meshToSearch(t)
+	if hits := x.search("machine converged"); len(hits) != 1 || hits[0].Address != "mesh-controller.nodes" {
+		t.Errorf("words in a description: %+v", hits)
+	}
+	if hits := x.search("journalctl kubernetes"); len(hits) != 1 || hits[0].Address != "anchor/node-service-manager.journal" {
+		t.Errorf("a command with arguments nothing has is still that command: %+v", hits)
+	}
+	if hits := x.search("kubernetes"); len(hits) != 0 {
+		t.Errorf("a word nothing has matched: %+v", hits)
+	}
+	x.Modules["shell"] = &moduleInfo{Module: "shell", On: []string{"anchor"}, Tools: []Tool{{Module: "shell", Name: "shell_login",
+		Description: "The account's login shell."}}}
+	for _, h := range x.search("logs") {
+		if h.Address == "anchor/shell.shell_login" {
+			t.Errorf("`logs` found `login` through its synonym `log`: %+v", h)
+		}
+	}
+}
+
+// A controller older than `replaces` answers without it: search matches names and descriptions as before.
+func TestSearchWithoutReplacesMatchesAsBefore(t *testing.T) {
+	x := meshToSearch(t)
+	x.Replaces = replacesOf(json.RawMessage(`{"seats":[{"seat":"node-service-manager","tools":[{"name":"journal"}]}]}`),
+		[]recordedModule{{Module: "docker"}})
+	if len(x.Replaces) != 0 {
+		t.Fatalf("replaces from records that have none: %v", x.Replaces)
+	}
+	if hits := x.search("journal"); len(hits) == 0 || hits[0].Address != "anchor/node-service-manager.journal" {
+		t.Errorf("a verb's own name: %+v", hits)
+	}
+	if hits := x.search("docker logs"); len(hits) == 0 || hits[0].Address != "anchor/docker.docker_logs" {
+		t.Errorf("a tool's own name: %+v", hits)
+	}
+}

node-tools/internal/launch/error_code_test.go

@@ -0,0 +1,30 @@
+package launch
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+)
+
+type lostWrite struct{}
+
+func (lostWrite) Error() string {
+	return "issues.numbers.issue: the key was written by another writer first"
+}
+func (lostWrite) ErrorCode() int { return CodeChanged }
+
+// A lost compare-and-set is answered to a bundle with its own code, wrapped or not, and the SDK tells it by
+// that code alone (mesh-sdk's stdio.CodeChanged); every other refusal is the general code, never that one.
+func TestALostWriteIsAnsweredWithItsOwnCodeAndNothingElseIs(t *testing.T) {
+	if CodeChanged != -32010 {
+		t.Fatalf("the lost-write code is %d; mesh-sdk tells it by -32010", CodeChanged)
+	}
+	for _, err := range []error{lostWrite{}, fmt.Errorf("asked by issues: %w", lostWrite{})} {
+		if got := errorCode(err); got != CodeChanged {
+			t.Errorf("%v is answered %d", err, got)
+		}
+	}
+	if got := errorCode(errors.New("issues keeps no state numbers")); got == CodeChanged || got != -32000 {
+		t.Errorf("a plain refusal is answered %d", got)
+	}
+}

node-tools/internal/launch/event_answer_test.go

@@ -0,0 +1,93 @@
+package launch
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"path/filepath"
+	"sync"
+	"testing"
+	"time"
+)
+
+// A bundle that answers `mesh/event` as $ANSWER says: an error, a result, or an answer with neither.
+const answeringBundle = `#!/bin/sh
+while IFS= read -r line; do
+  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
+  case "$line" in
+    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
+    *'"method":"tools/list"'*)
+      printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
+      printf '{"jsonrpc":"2.0","id":"s1","method":"mesh/subscribe","params":{"pattern":"#"}}\n' ;;
+    *'"method":"mesh/event"'*)
+      case "$ANSWER" in
+        error) printf '{"jsonrpc":"2.0","id":%s,"error":{"code":-32000,"message":"Unexpected end of JSON input"}}\n' "$id" ;;
+        result) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
+        bare) printf '{"jsonrpc":"2.0","id":%s}\n' "$id" ;;
+      esac ;;
+  esac
+done
+`
+
+type subscribing struct {
+	mu      sync.Mutex
+	deliver func(json.RawMessage) error
+}
+
+func (b *subscribing) Publish(json.RawMessage) error                          { return nil }
+func (b *subscribing) Ask(json.RawMessage) (json.RawMessage, error)           { return nil, nil }
+func (b *subscribing) State(string, json.RawMessage) (json.RawMessage, error) { return nil, nil }
+func (b *subscribing) Log(string, json.RawMessage) (json.RawMessage, error)   { return nil, nil }
+func (b *subscribing) Watch(json.RawMessage, func(json.RawMessage) error) (func(), error) {
+	return func() {}, nil
+}
+func (b *subscribing) Seat(string, json.RawMessage, func(string, any) (json.RawMessage, error)) (json.RawMessage, error) {
+	return nil, nil
+}
+func (b *subscribing) Subscribe(d func(json.RawMessage) error) error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	b.deliver = d
+	return nil
+}
+
+func deliverTo(t *testing.T, answer string) error {
+	t.Helper()
+	entry := filepath.Join(t.TempDir(), "bundle")
+	if err := os.WriteFile(entry, []byte(answeringBundle), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	b := &subscribing{}
+	l, err := Start("plex", entry, append(os.Environ(), "ANSWER="+answer), b, t.Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(l.Stop)
+	for i := 0; ; i++ {
+		b.mu.Lock()
+		d := b.deliver
+		b.mu.Unlock()
+		if d != nil {
+			return d(json.RawMessage(`{"key":"radarr.download.completed","body":{"title":"x"}}`))
+		}
+		if i > 100 {
+			t.Fatal("the bundle never subscribed")
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
+}
+
+// An event is taken by any answer that is not an error, and not taken by an error, which reaches the
+// runtime as the bundle's own words — not as something the runtime failed to read (hq issue 276).
+func TestAnEventIsTakenByAnyAnswerThatIsNotAnError(t *testing.T) {
+	for _, answer := range []string{"result", "bare"} {
+		if err := deliverTo(t, answer); err != nil {
+			t.Errorf("an answer %q did not take the event: %v", answer, err)
+		}
+	}
+	err := deliverTo(t, "error")
+	var refused *Refused
+	if !errors.As(err, &refused) || refused.Method != "mesh/event" || refused.Message != "Unexpected end of JSON input" {
+		t.Fatalf("an error answer was not the bundle's refusal of mesh/event: %#v", err)
+	}
+}

node-tools/internal/launch/launch.go

@@ -0,0 +1,651 @@
+// Package launch starts a bundle the runtime serves and speaks MCP over stdio to it (novox/hq ADR
+// 0188, ADR 0193): `initialize`, `tools/list` once, `tools/call` per call. A Go binary, a Python
+// script and a Node launcher are the same thing here: an executable that answers those. The runtime
+// knows no language; it starts the path it is given.
+package launch
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/novox/mesh-tools/node-tools/internal/wire"
+)
+
+// Protocol is the MCP version spoken to a bundle.
+const Protocol = "2025-03-26"
+
+// How long a child has for its handshake, and a call before the caller is told it is slow.
+var (
+	HandshakeTimeout = 10 * time.Second
+	CallTimeout      = 30 * time.Second
+)
+
+// Tool is one tool a launched bundle listed, and how to call it.
+type Tool struct {
+	Name        string
+	Description string
+	Input       json.RawMessage
+	// Run calls the tool for caller: the bus user the call's subject named, or "" when it named none. A
+	// caller is handed to the bundle in the call's `_meta` (MetaCaller), never among its arguments.
+	Run func(caller string, args json.RawMessage) (json.RawMessage, error)
+}
+
+// MetaCaller is where in a `tools/call`'s `_meta` the runtime names the caller it took from the subject the
+// call arrived on (novox/hq issue 365): mesh-sdk's stdio.MetaCaller, which hands it to the tool as
+// stdio.CallerOf, and says Unproven when it is absent.
+const MetaCaller = "mesh/caller"
+
+// callParams is a `tools/call`'s params: the tool, its arguments as the caller sent them, and — only when the
+// subject named one — the caller, in `_meta`, which the runtime writes and no caller can.
+func callParams(name, caller string, args json.RawMessage) map[string]any {
+	params := map[string]any{"name": name, "arguments": args}
+	if caller != "" {
+		params["_meta"] = map[string]any{MetaCaller: caller}
+	}
+	return params
+}
+
+// Registration is the tools a bundle listed under one name: its module's, or a seat's.
+type Registration struct {
+	Module string
+	Tools  []Tool
+}
+
+// Bus is what a launched bundle reaches the mesh through (novox/hq ADR 0193, ADR 0198): the runtime
+// publishes, asks and subscribes on the module's behalf. Subscribe is asked each time the module's
+// code subscribes; the runtime binds the module's consumer once and calls deliver for every event,
+// acknowledging it on the bus when deliver returns nil.
+//
+// State and Watch reach the module's state (novox/hq ADR 0201): State answers `get`, `put`, `delete`
+// and `keys`; Watch hands deliver the current values and then every change, and returns once the
+// current values are delivered — the watch is the child's, and stops when the child does.
+type Bus interface {
+	Publish(params json.RawMessage) error
+	Ask(params json.RawMessage) (json.RawMessage, error)
+	Subscribe(deliver func(envelope json.RawMessage) error) error
+	State(verb string, params json.RawMessage) (json.RawMessage, error)
+	Watch(params json.RawMessage, deliver func(change json.RawMessage) error) (stop func(), err error)
+	// Log answers a bundle's `append`, `read`, `last` and `info` on its module's log (novox/hq ADR 0297).
+	Log(verb string, params json.RawMessage) (json.RawMessage, error)
+	// Seat answers a bundle's seat traffic (novox/hq ADR 0259 §3): `publish`, `prove` and `record` at once;
+	// `take` and `answer` bind once and hand each message or proof on through handOn, to whichever child
+	// of the module asked last — a restarted child asks again as its code runs again.
+	Seat(verb string, params json.RawMessage, handOn func(method string, params any) (json.RawMessage, error)) (json.RawMessage, error)
+}
+
+// EventTimeout bounds how long a bundle has to handle one event before it is offered again.
+var EventTimeout = 2 * time.Minute
+
+// Refused is a bundle's error answer to what the runtime asked it: the bundle's own words, as opposed
+// to the runtime not reaching it (not running, exited, no answer in time). For `mesh/event` it is the
+// one way a bundle says it did not take an event: any answer that is not an error — `{}`, `null`, no
+// result at all — takes it (mesh-sdk, "Taking an event"; novox/hq issue 276).
+type Refused struct {
+	Method  string
+	Message string
+}
+
+func (r *Refused) Error() string { return r.Message }
+
+// Restart backoff: a bundle that exits is started again at once, then after growing pauses while it
+// keeps exiting, back to at once once it has run a while.
+var (
+	RestartFirst  = 500 * time.Millisecond
+	RestartMost   = 30 * time.Second
+	RestartSettle = time.Minute
+)
+
+// StopWait bounds how long Launched.Stop waits for its bundle's exit to be handled; a bundle that
+// ignores SIGTERM longer than this is left to exit on its own (novox/hq issue 476).
+var StopWait = 5 * time.Second
+
+// Launched is a running bundle: what it registered, and how to stop it.
+type Launched struct {
+	Registrations []Registration
+	Stop          func()
+}
+
+// Executable says whether an entrypoint can be started: a bundle the runtime serves is executable,
+// and one that is not was not built to be served (ADR 0193).
+func Executable(path string) bool {
+	info, err := os.Stat(path)
+	if err != nil || info.IsDir() {
+		return false
+	}
+	return info.Mode().Perm()&0o111 != 0
+}
+
+type message struct {
+	JSONRPC string          `json:"jsonrpc,omitempty"`
+	ID      json.RawMessage `json:"id,omitempty"`
+	Method  string          `json:"method,omitempty"`
+	Params  json.RawMessage `json:"params,omitempty"`
+	Result  json.RawMessage `json:"result,omitempty"`
+	Error   *struct {
+		Code    int    `json:"code"`
+		Message string `json:"message"`
+	} `json:"error,omitempty"`
+}
+
+type child struct {
+	cmd     *exec.Cmd
+	stdin   io.WriteCloser
+	writeMu sync.Mutex
+	mu      sync.Mutex
+	pending map[int64]chan message
+	next    int64
+	dead    chan struct{}
+	// handled is closed once the child's exit has been handled whole — its state cleared and its
+	// restart decided — which Stop waits for (novox/hq issue 476).
+	handled chan struct{}
+	why     error
+	// watches are the state watches this child asked for, stopped when it exits (ADR 0201): a child
+	// that starts again watches again, as its code runs again.
+	watches []func()
+}
+
+func (c *child) write(m any) error {
+	b, err := wire.Marshal(m)
+	if err != nil {
+		return err
+	}
+	c.writeMu.Lock()
+	defer c.writeMu.Unlock()
+	_, err = c.stdin.Write(append(b, '\n'))
+	return err
+}
+
+var stackLine = regexp.MustCompile(`^\s+at\s`)
+
+// Start launches one bundle and learns its tools. It fails when the child cannot be started or does
+// not complete the handshake. A child that exits later is started again on its next call.
+func Start(module, entry string, env []string, mesh Bus, logf func(string, ...any)) (*Launched, error) {
+	var mu sync.Mutex
+	var current *child
+	// The child that last subscribed is the one events are handed to: a restarted child subscribes
+	// again as its code is imported, and from then on the module's events are its.
+	var subscriber *child
+	// The child that last asked to take a seat's work or answer its proofs is the one they are handed to.
+	var seatTaker *child
+	handOn := func(method string, params any) (json.RawMessage, error) {
+		mu.Lock()
+		c := seatTaker
+		mu.Unlock()
+		if c == nil {
+			return nil, errors.New(module + "'s bundle is not running to take it")
+		}
+		return c.ask(module, method, params, EventTimeout)
+	}
+	stopped := false
+	deliver := func(envelope json.RawMessage) error {
+		mu.Lock()
+		c := subscriber
+		mu.Unlock()
+		if c == nil {
+			return errors.New(module + "'s bundle is not running to take its events")
+		}
+		// Taken unless the answer is an error; what a result says is not read (see Refused).
+		_, err := c.ask(module, "mesh/event", map[string]any{"envelope": envelope}, EventTimeout)
+		return err
+	}
+	var restart func(after time.Duration)
+	var startedAt time.Time
+	// The restart pauses are read once, here: the exit handling runs on its own goroutine and must not
+	// read the package's settings while a caller (a test) changes them (novox/hq issue 476).
+	pauseFirst, pauseMost, settle := RestartFirst, RestartMost, RestartSettle
+	pause := pauseFirst
+
+	start := func() (*child, error) {
+		cmd := exec.Command(entry)
+		cmd.Env = env
+		stdin, err := cmd.StdinPipe()
+		if err != nil {
+			return nil, err
+		}
+		stdout, err := cmd.StdoutPipe()
+		if err != nil {
+			return nil, err
+		}
+		stderr, err := cmd.StderrPipe()
+		if err != nil {
+			return nil, err
+		}
+		if err := cmd.Start(); err != nil {
+			return nil, err
+		}
+		c := &child{cmd: cmd, stdin: stdin, pending: map[int64]chan message{}, next: 1, dead: make(chan struct{}),
+			handled: make(chan struct{})}
+		var lastSaid string
+		var saidMu sync.Mutex
+		stderrDone := make(chan struct{})
+		go func() {
+			defer close(stderrDone)
+			scan := bufio.NewScanner(stderr)
+			scan.Buffer(make([]byte, 64*1024), 1<<20)
+			for scan.Scan() {
+				line := scan.Text()
+				if strings.TrimSpace(line) == "" {
+					continue
+				}
+				logf("[%s] %s", module, line)
+				if !stackLine.MatchString(line) && !strings.HasPrefix(line, "Node.js v") {
+					saidMu.Lock()
+					lastSaid = strings.TrimSpace(line)
+					saidMu.Unlock()
+				}
+			}
+		}()
+		go func() {
+			defer close(c.handled)
+			scan := bufio.NewScanner(stdout)
+			scan.Buffer(make([]byte, 64*1024), 16<<20)
+			for scan.Scan() {
+				line := strings.TrimSpace(scan.Text())
+				if line == "" {
+					continue
+				}
+				var m message
+				if err := json.Unmarshal([]byte(line), &m); err != nil {
+					if len(line) > 120 {
+						line = line[:120]
+					}
+					logf("[mesh-tools] %s's bundle said something that is not a reply: %s", module, line)
+					continue
+				}
+				// The bundle asks the runtime (ADR 0193, ADR 0198): to emit, to call a tool, to hand it the
+				// module's events. Each on the module's behalf, answered when done; nothing else.
+				if m.Method != "" {
+					go func(m message) {
+						var result any = map[string]any{}
+						var err error
+						switch m.Method {
+						case "mesh/publish":
+							err = mesh.Publish(m.Params)
+						case "mesh/ask":
+							var asked json.RawMessage
+							if asked, err = mesh.Ask(m.Params); err == nil {
+								result = asked
+							}
+						case "mesh/subscribe":
+							mu.Lock()
+							subscriber = c
+							mu.Unlock()
+							err = mesh.Subscribe(deliver)
+						case "mesh/seat.publish", "mesh/seat.prove", "mesh/seat.record", "mesh/seat.kinds":
+							var answered json.RawMessage
+							if answered, err = mesh.Seat(strings.TrimPrefix(m.Method, "mesh/seat."), m.Params, nil); err == nil {
+								result = answered
+							}
+						case "mesh/seat.take", "mesh/seat.answer":
+							mu.Lock()
+							seatTaker = c
+							mu.Unlock()
+							var answered json.RawMessage
+							if answered, err = mesh.Seat(strings.TrimPrefix(m.Method, "mesh/seat."), m.Params, handOn); err == nil {
+								result = answered
+							}
+						case "mesh/state.get", "mesh/state.put", "mesh/state.delete", "mesh/state.keys",
+							"mesh/state.create", "mesh/state.update", "mesh/state.history":
+							var answered json.RawMessage
+							if answered, err = mesh.State(strings.TrimPrefix(m.Method, "mesh/state."), m.Params); err == nil {
+								result = answered
+							}
+						case "mesh/log.append", "mesh/log.read", "mesh/log.last", "mesh/log.info":
+							var answered json.RawMessage
+							if answered, err = mesh.Log(strings.TrimPrefix(m.Method, "mesh/log."), m.Params); err == nil {
+								result = answered
+							}
+						case "mesh/state.watch":
+							// Each change is asked of this child, in order, naming the watch it is for by
+							// the id the child asked it with — two watches of one state are two handlers;
+							// the watch is answered once the current values have been handed over, so a
+							// bundle that awaits it has the whole of the state before it goes on (ADR 0201).
+							var stop func()
+							watch := m.ID
+							stop, err = mesh.Watch(m.Params, func(change json.RawMessage) error {
+								_, err := c.ask(module, "mesh/state", map[string]any{"watch": watch, "change": change}, EventTimeout)
+								return err
+							})
+							if err == nil {
+								c.mu.Lock()
+								if c.why != nil {
+									c.mu.Unlock()
+									stop()
+								} else {
+									c.watches = append(c.watches, stop)
+									c.mu.Unlock()
+								}
+							}
+						default:
+							if len(m.ID) > 0 {
+								_ = c.write(map[string]any{"jsonrpc": "2.0", "id": m.ID,
+									"error": map[string]any{"code": -32601, "message": "the runtime answers no " + m.Method + " from a bundle"}})
+							}
+							return
+						}
+						if len(m.ID) == 0 {
+							return
+						}
+						if err != nil {
+							_ = c.write(map[string]any{"jsonrpc": "2.0", "id": m.ID,
+								"error": map[string]any{"code": errorCode(err), "message": err.Error()}})
+							return
+						}
+						_ = c.write(map[string]any{"jsonrpc": "2.0", "id": m.ID, "result": result})
+					}(m)
+					continue
+				}
+				var id int64
+				if json.Unmarshal(m.ID, &id) != nil {
+					continue
+				}
+				c.mu.Lock()
+				ch := c.pending[id]
+				delete(c.pending, id)
+				c.mu.Unlock()
+				if ch != nil {
+					ch <- m
+				}
+			}
+			<-stderrDone
+			err := cmd.Wait()
+			code := "0"
+			if exit := (*exec.ExitError)(nil); errors.As(err, &exit) {
+				if status, ok := exit.Sys().(syscall.WaitStatus); ok && status.Signaled() {
+					code = unix.SignalName(status.Signal())
+				} else {
+					code = fmt.Sprint(exit.ExitCode())
+				}
+			}
+			saidMu.Lock()
+			why := fmt.Sprintf("%s's bundle exited (%s)", module, code)
+			if lastSaid != "" {
+				why += ": " + lastSaid
+			}
+			saidMu.Unlock()
+			c.mu.Lock()
+			c.why = errors.New(why)
+			watches := c.watches
+			c.watches = nil
+			c.mu.Unlock()
+			for _, stop := range watches {
+				stop()
+			}
+			close(c.dead)
+			mu.Lock()
+			// Only a child that was serving is brought back; one that died in its own handshake was
+			// never accepted, and whoever started it was told why.
+			wasServing := current == c
+			if current == c {
+				current = nil
+			}
+			if subscriber == c {
+				subscriber = nil
+			}
+			if seatTaker == c {
+				seatTaker = nil
+			}
+			wasStopped := stopped
+			// Started again at once if it ran a while; after a growing pause while it keeps exiting.
+			wait := pauseFirst
+			if time.Since(startedAt) < settle {
+				wait = pause
+				if pause *= 2; pause > pauseMost {
+					pause = pauseMost
+				}
+			} else {
+				pause = pauseFirst
+			}
+			mu.Unlock()
+			if !wasStopped && wasServing {
+				// Every bundle stays up (ADR 0198): code that runs long — a handler, a provisioner —
+				// is not waiting for a call to bring it back, and a tool bundle back early costs nothing.
+				logf("[mesh-tools] %s; started again in %s", why, wait.Round(100*time.Millisecond))
+				restart(wait)
+			}
+		}()
+		if _, err := c.ask(module, "initialize", map[string]any{"protocolVersion": Protocol, "capabilities": map[string]any{},
+			"clientInfo": map[string]any{"name": "node-tools", "version": "1"}}, HandshakeTimeout); err != nil {
+			_ = cmd.Process.Kill()
+			return nil, err
+		}
+		_ = c.write(map[string]any{"jsonrpc": "2.0", "method": "notifications/initialized"})
+		return c, nil
+	}
+
+	asking := func(method string, params any, timeout time.Duration) (json.RawMessage, error) {
+		mu.Lock()
+		c := current
+		mu.Unlock()
+		if c == nil {
+			fresh, err := start()
+			if err != nil {
+				return nil, err
+			}
+			mu.Lock()
+			if current == nil {
+				current = fresh
+				startedAt = time.Now()
+			} else {
+				_ = fresh.cmd.Process.Signal(syscall.SIGTERM)
+				fresh = current
+			}
+			c = fresh
+			mu.Unlock()
+		}
+		return c.ask(module, method, params, timeout)
+	}
+
+	restart = func(after time.Duration) {
+		go func() {
+			time.Sleep(after)
+			mu.Lock()
+			if stopped || current != nil {
+				mu.Unlock()
+				return
+			}
+			mu.Unlock()
+			fresh, err := start()
+			mu.Lock()
+			defer mu.Unlock()
+			if err != nil {
+				if !stopped {
+					wait := pause
+					if pause *= 2; pause > pauseMost {
+						pause = pauseMost
+					}
+					logf("[mesh-tools] %s's bundle did not start again: %v; trying in %s", module, err, wait)
+					go restart(wait)
+				}
+				return
+			}
+			if stopped {
+				_ = fresh.cmd.Process.Signal(syscall.SIGTERM)
+				return
+			}
+			if current == nil {
+				current = fresh
+				startedAt = time.Now()
+			} else {
+				_ = fresh.cmd.Process.Signal(syscall.SIGTERM)
+			}
+		}()
+	}
+
+	first, err := start()
+	if err != nil {
+		return nil, err
+	}
+	mu.Lock()
+	current = first
+	startedAt = time.Now()
+	mu.Unlock()
+
+	raw, err := asking("tools/list", map[string]any{}, HandshakeTimeout)
+	if err != nil {
+		return nil, err
+	}
+	var listed struct {
+		Tools []struct {
+			Name        string          `json:"name"`
+			Description string          `json:"description"`
+			InputSchema json.RawMessage `json:"inputSchema"`
+		} `json:"tools"`
+	}
+	if err := json.Unmarshal(raw, &listed); err != nil {
+		return nil, fmt.Errorf("%s's bundle listed its tools in a shape that is not MCP's: %w", module, err)
+	}
+	order := []string{}
+	groups := map[string][]Tool{}
+	for _, t := range listed.Tools {
+		under, name := module, t.Name
+		if dot := strings.Index(t.Name, "."); dot >= 0 {
+			under, name = t.Name[:dot], t.Name[dot+1:]
+		}
+		full := t.Name
+		input := t.InputSchema
+		if len(input) == 0 || string(input) == "null" {
+			input = json.RawMessage("{}")
+		}
+		tool := Tool{Name: name, Description: t.Description, Input: input,
+			Run: func(caller string, args json.RawMessage) (json.RawMessage, error) {
+				if len(args) == 0 || string(args) == "null" {
+					args = json.RawMessage("{}")
+				}
+				res, err := asking("tools/call", callParams(full, caller, args), CallTimeout)
+				if err != nil {
+					return nil, err
+				}
+				var called struct {
+					Content []struct {
+						Type string `json:"type"`
+						Text string `json:"text"`
+					} `json:"content"`
+					IsError bool `json:"isError"`
+				}
+				_ = json.Unmarshal(res, &called)
+				text := ""
+				for _, c := range called.Content {
+					if c.Type == "text" {
+						text = c.Text
+						break
+					}
+				}
+				if called.IsError {
+					if text == "" {
+						text = module + "." + full + " failed"
+					}
+					return nil, errors.New(text)
+				}
+				// The bundle's answer is JSON as text; handed back as the value it encodes.
+				if json.Valid([]byte(text)) && text != "" {
+					return json.RawMessage(text), nil
+				}
+				b, _ := json.Marshal(text)
+				return b, nil
+			}}
+		if _, seen := groups[under]; !seen {
+			order = append(order, under)
+		}
+		groups[under] = append(groups[under], tool)
+	}
+	out := &Launched{Stop: func() {
+		mu.Lock()
+		stopped = true
+		c := current
+		current = nil
+		mu.Unlock()
+		if c != nil && c.cmd.Process != nil {
+			_ = c.cmd.Process.Signal(syscall.SIGTERM)
+			// Returns once the bundle's exit is handled, so nothing of it runs on after Stop
+			// (novox/hq issue 476); bounded, for a bundle that does not exit on SIGTERM.
+			select {
+			case <-c.handled:
+			case <-time.After(StopWait):
+			}
+		}
+	}}
+	for _, under := range order {
+		out.Registrations = append(out.Registrations, Registration{Module: under, Tools: groups[under]})
+	}
+	return out, nil
+}
+
+func (c *child) ask(module, method string, params any, timeout time.Duration) (json.RawMessage, error) {
+	c.mu.Lock()
+	if c.why != nil {
+		c.mu.Unlock()
+		return nil, c.why
+	}
+	id := c.next
+	c.next++
+	ch := make(chan message, 1)
+	c.pending[id] = ch
+	c.mu.Unlock()
+	if err := c.write(map[string]any{"jsonrpc": "2.0", "id": id, "method": method, "params": params}); err != nil {
+		c.mu.Lock()
+		delete(c.pending, id)
+		c.mu.Unlock()
+		select {
+		case <-c.dead:
+			return nil, c.deathReason()
+		case <-time.After(100 * time.Millisecond):
+			return nil, err
+		}
+	}
+	timer := time.NewTimer(timeout)
+	defer timer.Stop()
+	select {
+	case m := <-ch:
+		if m.Error != nil {
+			msg := m.Error.Message
+			if msg == "" {
+				msg = "the bundle refused the request"
+			}
+			return nil, &Refused{Method: method, Message: msg}
+		}
+		return m.Result, nil
+	case <-c.dead:
+		return nil, c.deathReason()
+	case <-timer.C:
+		c.mu.Lock()
+		delete(c.pending, id)
+		c.mu.Unlock()
+		return nil, fmt.Errorf("%s's bundle did not answer %s in %ds", module, method, int(timeout/time.Second))
+	}
+}
+
+func (c *child) deathReason() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.why != nil {
+		return c.why
+	}
+	return errors.New("the bundle exited")
+}
+
+// CodeChanged is the error code a bundle is answered a lost compare-and-set with (mesh-sdk's
+// stdio.CodeChanged): told by its code, never by its words (novox/hq ADR 0259).
+const CodeChanged = -32010
+
+// errorCode is the code an error is answered to a bundle with: a lost compare-and-set's own, else the
+// general one.
+func errorCode(err error) int {
+	var coded interface{ ErrorCode() int }
+	if errors.As(err, &coded) {
+		return coded.ErrorCode()
+	}
+	return -32000
+}

node-tools/internal/launch/seat_test.go

@@ -0,0 +1,71 @@
+package launch
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"sync"
+	"testing"
+	"time"
+)
+
+// A bundle that asks to take a worker's work and answers each piece it is handed.
+const takingBundle = `#!/bin/sh
+while IFS= read -r line; do
+  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
+  case "$line" in
+    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
+    *'"method":"tools/list"'*)
+      printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
+      printf '{"jsonrpc":"2.0","id":"s1","method":"mesh/seat.take","params":{"worker":"SEAT_CHANNEL_TELEGRAM_worker"}}\n' ;;
+    *'"method":"mesh/work"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{"taken":true}}\n' "$id" ;;
+  esac
+done
+`
+
+type seating struct {
+	subscribing
+	mu     sync.Mutex
+	verb   string
+	params string
+	handOn func(string, any) (json.RawMessage, error)
+}
+
+func (b *seating) Seat(verb string, params json.RawMessage, handOn func(string, any) (json.RawMessage, error)) (json.RawMessage, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	b.verb, b.params, b.handOn = verb, string(params), handOn
+	return json.RawMessage(`{}`), nil
+}
+
+// novox/hq ADR 0259 §3: a bundle's seat traffic reaches the runtime's bus from its own channel, and the work
+// it takes is handed back to it.
+func TestABundleTakesASeatsWorkThroughItsOwnChannel(t *testing.T) {
+	entry := filepath.Join(t.TempDir(), "bundle")
+	if err := os.WriteFile(entry, []byte(takingBundle), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	b := &seating{}
+	l, err := Start("telegram", entry, os.Environ(), b, t.Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(l.Stop)
+	var handOn func(string, any) (json.RawMessage, error)
+	for i := 0; handOn == nil; i++ {
+		if i > 100 {
+			t.Fatal("the bundle never asked to take its work")
+		}
+		time.Sleep(20 * time.Millisecond)
+		b.mu.Lock()
+		handOn = b.handOn
+		b.mu.Unlock()
+	}
+	if b.verb != "take" || b.params != `{"worker":"SEAT_CHANNEL_TELEGRAM_worker"}` {
+		t.Fatalf("asked %s %s", b.verb, b.params)
+	}
+	got, err := handOn("mesh/work", map[string]any{"work": map[string]any{"subject": "mesh.seat.channel.accept.show.telegram"}})
+	if err != nil || string(got) != `{"taken":true}` {
+		t.Fatalf("the work was not handed to the bundle: %s %v", got, err)
+	}
+}

node-tools/internal/meshtest/meshtest.go

@@ -0,0 +1,273 @@
+// Package meshtest raises what the controller would, for tests against a real bus: the ASSIGNMENTS
+// and EVENTS streams, memberships issued by hand, and a fixture's path.
+//
+// **Every test has a bus of its own** (novox/hq ADR 0237, the controller's internal/testbus): a server
+// linked in at the release go.mod pins — the release the mesh runs, held so by a test beside this one —
+// started for the one test and gone after it. The packages shared one bus and had to run one at a time:
+// each test raised the streams afresh, and the console discovers every runtime that announces itself on
+// the bus (ADR 0197), so a runtime from another package's test was, correctly, found. Now the suite runs
+// as Go runs it, in parallel and under the race detector. A person may still point a run at a bus of
+// their own with MESH_TEST_NATS_EXTERNAL=1 and MESH_TEST_NATS; then the run is theirs to serialise.
+package meshtest
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats-server/v2/server"
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// Version is the release of the server the tests run.
+const Version = server.VERSION
+
+// URL is the bus of this test alone: started at its first ask, the same one at every ask after — a test
+// that dials twice, or hands the address to the code it tests, reaches one bus — and shut down when the
+// test ends.
+func URL(t *testing.T) string {
+	t.Helper()
+	if os.Getenv("MESH_TEST_NATS_EXTERNAL") == "1" {
+		if url := os.Getenv("MESH_TEST_NATS"); url != "" {
+			return url
+		}
+		t.Fatal("MESH_TEST_NATS_EXTERNAL=1 and MESH_TEST_NATS names no bus")
+	}
+	if url, ok := buses.Load(t); ok {
+		return url.(string)
+	}
+	opts := &server.Options{Host: "127.0.0.1", Port: server.RANDOM_PORT, JetStream: true, StoreDir: t.TempDir(),
+		NoLog: true, NoSigs: true}
+	s, err := server.NewServer(opts)
+	if err != nil {
+		t.Fatalf("a bus for this test could not be made: %v", err)
+	}
+	go s.Start()
+	if !s.ReadyForConnections(30 * time.Second) {
+		s.Shutdown()
+		t.Fatal("a bus for this test did not come up within 30s")
+	}
+	url := s.ClientURL()
+	buses.Store(t, url)
+	t.Cleanup(func() {
+		buses.Delete(t)
+		s.Shutdown()
+		s.WaitForShutdown()
+	})
+	return url
+}
+
+// buses are the running tests' buses, by test.
+var buses sync.Map
+
+// Mesh is the controller's job, done by hand.
+type Mesh struct {
+	nc *nats.Conn
+	js nats.JetStreamContext
+}
+
+// New raises the streams afresh.
+func New(t *testing.T) *Mesh {
+	t.Helper()
+	nc, err := nats.Connect(URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	js, _ := nc.JetStream()
+	for _, s := range []string{"ASSIGNMENTS", "EVENTS"} {
+		_ = js.DeleteStream(s)
+	}
+	if _, err := js.AddStream(&nats.StreamConfig{Name: "ASSIGNMENTS", Subjects: []string{"mesh.assignment.>"},
+		MaxMsgsPerSubject: 1, AllowDirect: true}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := js.AddStream(&nats.StreamConfig{Name: "EVENTS", Subjects: []string{"mesh.mod.*.event.>"}}); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(nc.Close)
+	return &Mesh{nc: nc, js: js}
+}
+
+// Issue publishes a membership.
+func (m *Mesh) Issue(t *testing.T, mem bus.Membership) {
+	t.Helper()
+	body, _ := json.Marshal(mem)
+	if _, err := m.js.Publish(bus.MembershipSubject(mem.Node, mem.Module), body); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// NextEvent is the subject the next event under a pattern lands on.
+func (m *Mesh) NextEvent(t *testing.T, pattern string) <-chan string {
+	t.Helper()
+	ch := make(chan string, 1)
+	sub, err := m.nc.Subscribe(pattern, func(msg *nats.Msg) {
+		select {
+		case ch <- msg.Subject:
+		default:
+		}
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = sub.Unsubscribe() })
+	_ = m.nc.Flush()
+	return ch
+}
+
+// MembershipOf is a membership as the controller issues one on a machine.
+func MembershipOf(module, node string, plain bool, seats map[string][]string) bus.Membership {
+	own := "mesh.mod." + module
+	serves := []bus.Served{{Subject: own + ".tool.{tool}." + node}}
+	if plain {
+		serves = append(serves, bus.Served{Subject: own + ".tool.{tool}", Queue: "serve." + module})
+	}
+	var verbs []bus.SeatVerb
+	for seat, vs := range seats {
+		for _, v := range vs {
+			verbs = append(verbs, bus.SeatVerb{Seat: seat, Verb: v, Subject: "mesh.seat." + seat + ".tool." + v + "." + node})
+		}
+	}
+	return bus.Membership{Node: node, Module: module, Serves: serves, Seats: verbs,
+		Emits: own + ".event.{event}", Tools: own + ".tool.tools"}
+}
+
+// Fixture is a path in node-tools/test/fixtures, which these tests share with the TypeScript ones.
+func Fixture(name string) string {
+	_, here, _, _ := runtime.Caller(0)
+	return filepath.Join(filepath.Dir(here), "..", "..", "test", "fixtures", name)
+}
+
+// Until retries while the bus answers "no responders" — something not yet served.
+func Until(t *testing.T, try func() error) {
+	t.Helper()
+	var err error
+	for i := 0; i < 50; i++ {
+		if err = try(); err == nil {
+			return
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	t.Fatal(err)
+}
+
+// Logs collects what the runtime says.
+type Logs struct{ lines []string }
+
+// Logf is a logger that keeps the lines.
+func (l *Logs) Logf(format string, args ...any) {
+	l.lines = append(l.lines, sprintf(format, args...))
+}
+
+// Has says whether a line contains every fragment.
+func (l *Logs) Has(fragments ...string) bool {
+	for _, line := range l.lines {
+		all := true
+		for _, f := range fragments {
+			all = all && strings.Contains(line, f)
+		}
+		if all {
+			return true
+		}
+	}
+	return false
+}
+
+// All is every line.
+func (l *Logs) All() string { return strings.Join(l.lines, "\n") }
+
+// Consumer makes a module's durable consumer on a machine as the controller does: pull, on the
+// EVENTS stream, filtered to what the module consumes, with a short ack wait so a test sees a
+// redelivery in seconds rather than the mesh's minutes.
+func (m *Mesh) Consumer(t *testing.T, node, module string, filters []string, ackWait time.Duration) {
+	t.Helper()
+	cfg := &nats.ConsumerConfig{Durable: node + "_" + module, AckPolicy: nats.AckExplicitPolicy,
+		AckWait: ackWait, MaxDeliver: 10, DeliverPolicy: nats.DeliverNewPolicy}
+	if len(filters) == 1 {
+		cfg.FilterSubject = filters[0]
+	} else {
+		cfg.FilterSubjects = filters
+	}
+	if _, err := m.js.AddConsumer("EVENTS", cfg); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Emit publishes an event as a module would, into the EVENTS stream.
+func (m *Mesh) Emit(t *testing.T, subject string, body any) {
+	t.Helper()
+	data, _ := json.Marshal(body)
+	if _, err := m.js.Publish(subject, data); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Pending is what a module's consumer still holds: delivered and not acknowledged, and not yet
+// delivered.
+func (m *Mesh) Pending(t *testing.T, node, module string) (ackPending, notDelivered uint64) {
+	t.Helper()
+	info, err := m.js.ConsumerInfo("EVENTS", node+"_"+module)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return uint64(info.NumAckPending), info.NumPending
+}
+
+// BucketKeeping makes a module's state afresh as Bucket does, keeping up to history values a key.
+func (m *Mesh) BucketKeeping(t *testing.T, name string, history uint8) nats.KeyValue {
+	t.Helper()
+	_ = m.js.DeleteKeyValue(name)
+	kv, err := m.js.CreateKeyValue(&nats.KeyValueConfig{Bucket: name, History: history, MaxValueSize: 256 * 1024})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return kv
+}
+
+// Bucket makes a module's state afresh as the controller does from the catalogue (novox/hq ADR 0201),
+// and answers it for writing what is there before a bundle starts.
+func (m *Mesh) Bucket(t *testing.T, name string) nats.KeyValue {
+	t.Helper()
+	_ = m.js.DeleteKeyValue(name)
+	kv, err := m.js.CreateKeyValue(&nats.KeyValueConfig{Bucket: name, History: 1, MaxValueSize: 256 * 1024})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return kv
+}
+
+// Log makes a module's log afresh as the controller does from the catalogue (novox/hq ADR 0297): a file
+// stream named LOG_<module>_<name> on mesh.log.<module>.<name>.>, limits retention, no age, no cap per
+// key, the declared cap, 260 KiB a message (a 256 KiB value and its headers), refusing new entries when full, direct get, no delete or
+// purge. It answers the membership entry the controller issues for it.
+func (m *Mesh) Log(t *testing.T, module, name string, maxBytes int64) bus.LogIssued {
+	t.Helper()
+	stream := "LOG_" + module + "_" + name
+	subject := "mesh.log." + module + "." + name
+	_ = m.js.DeleteStream(stream)
+	if _, err := m.js.AddStream(&nats.StreamConfig{Name: stream, Subjects: []string{subject + ".>"},
+		Storage: nats.FileStorage, Retention: nats.LimitsPolicy, MaxAge: 0, MaxMsgsPerSubject: -1,
+		MaxBytes: maxBytes, MaxMsgSize: 260 * 1024, Discard: nats.DiscardNew, AllowDirect: true,
+		DenyDelete: true, DenyPurge: true, Replicas: 1,
+		Description: module + "'s log " + name + ", kept as its record (novox/hq ADR 0297)"}); err != nil {
+		t.Fatal(err)
+	}
+	return bus.LogIssued{Name: name, Stream: stream, Subject: subject, Writes: true}
+}
+
+// Consumers is how many consumers a stream has.
+func (m *Mesh) Consumers(t *testing.T, stream string) int {
+	t.Helper()
+	info, err := m.js.StreamInfo(stream)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return info.State.Consumers
+}

node-tools/internal/meshtest/meshtest_test.go

@@ -0,0 +1,75 @@
+package meshtest
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+// **The bus the tests run is the bus the mesh runs** (novox/hq ADR 0227 rule 9, ADR 0237): the server linked
+// into the tests is held to the release the catalogue's bus image is — read from beside this checkout, as
+// the build seat clones it for a merge check — and, given the facts snapshot, to the release the mesh's bus
+// server says it runs. A bus upgrade moves the catalogue's pin; this then fails until go.mod's moves with it.
+func TestTheBusTheTestsRunIsTheBusTheMeshRuns(t *testing.T) {
+	beside := os.Getenv("MESH_CHECK_BESIDE")
+	if beside == "" {
+		beside = filepath.Join("..", "..", "..", "..")
+	}
+	dockerfile := filepath.Join(beside, "mesh-catalog", "modules", "nats", "Dockerfile")
+	raw, err := os.ReadFile(dockerfile)
+	switch {
+	case err == nil:
+		pinned := regexp.MustCompile(`upstream: nats ([0-9.]+)-alpine`).FindSubmatch(raw)
+		if pinned == nil {
+			t.Fatalf("%s says no release its digest is", dockerfile)
+		}
+		if string(pinned[1]) != Version {
+			t.Errorf("the tests run bus %s and the catalogue's bus image is %s: move go.mod's nats-server pin with the image",
+				Version, pinned[1])
+		}
+	case os.IsNotExist(err):
+		t.Logf("the catalogue is not beside this checkout, so its bus image is not compared")
+	default:
+		t.Fatal(err)
+	}
+	path := os.Getenv("MESH_FACTS")
+	if path == "" {
+		t.Logf("no MESH_FACTS: the bus the mesh runs is compared in a merge check, which has it")
+		return
+	}
+	body, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var f struct {
+		Taken    string `json:"taken"`
+		Versions struct {
+			Bus string `json:"bus"`
+		} `json:"versions"`
+	}
+	if err := json.Unmarshal(body, &f); err != nil {
+		t.Fatal(err)
+	}
+	if f.Versions.Bus != "" && strings.TrimPrefix(f.Versions.Bus, "v") != Version {
+		t.Errorf("the tests run bus %s and the mesh's bus runs %s (facts of %s)", Version, f.Versions.Bus, f.Taken)
+	}
+}
+
+// Each test is given a bus of its own, and the same one at every ask.
+func TestEachTestHasABusOfItsOwn(t *testing.T) {
+	var first string
+	t.Run("one", func(t *testing.T) {
+		first = URL(t)
+		if URL(t) != first {
+			t.Fatal("two buses for one test")
+		}
+	})
+	t.Run("two", func(t *testing.T) {
+		if URL(t) == first {
+			t.Fatal("two tests were given one bus")
+		}
+	})
+}

node-tools/internal/meshtest/sprintf.go

@@ -0,0 +1,5 @@
+package meshtest
+
+import "fmt"
+
+func sprintf(format string, args ...any) string { return fmt.Sprintf(format, args...) }

node-tools/internal/runtime/announce_test.go

@@ -0,0 +1,121 @@
+package runtime
+
+import (
+	"encoding/json"
+	"sort"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/micro"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// novox/hq ADR 0197: what a runtime serves, it announces — the NATS services protocol's discovery,
+// read here with NATS's own types, each endpoint a subject actually served — and the announcement
+// follows a re-issued membership.
+func TestTheRuntimeAnnouncesWhatItServesInTheServicesProtocol(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("alpha", "anchor", false, nil))
+	mesh.Issue(t, mt.MembershipOf("beta", "anchor", false, map[string][]string{"node-shelf": {"list", "clear"}}))
+	nodeTools := connect(t, "node-tools", "anchor")
+	stop, err := Run(nodeTools, []Served{
+		{"alpha", []string{mt.Fixture("many-alpha.serve.mjs")}},
+		{"beta", []string{mt.Fixture("many-beta.serve.mjs")}},
+	}, nil, (&mt.Logs{}).Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+
+	nc, err := nats.Connect(mt.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nc.Close()
+	info := func() micro.Info {
+		t.Helper()
+		msg, err := nc.Request("$SRV.INFO.node-tools.anchor", nil, 2*time.Second)
+		if err != nil {
+			t.Fatal(err)
+		}
+		var i micro.Info
+		if err := json.Unmarshal(msg.Data, &i); err != nil {
+			t.Fatal(err)
+		}
+		return i
+	}
+	subjects := func(i micro.Info) string {
+		var out []string
+		for _, e := range i.Endpoints {
+			out = append(out, e.Subject+"|"+e.QueueGroup+"|"+e.Metadata["kind"]+"|"+e.Metadata["module"]+"|"+e.Metadata["seat"]+"|"+e.Metadata["scope"]+"|"+e.Metadata["interchangeable"])
+		}
+		sort.Strings(out)
+		return strings.Join(out, "\n")
+	}
+
+	got := info()
+	if got.Type != micro.InfoResponseType || got.Name != "node-tools" || got.ID != "anchor" || got.Version == "" {
+		t.Errorf("identity: %+v", got.ServiceIdentity)
+	}
+	want := strings.Join([]string{
+		"mesh.mod.alpha.tool.one.anchor||tool|alpha|||false",
+		"mesh.mod.alpha.tool.two.anchor||tool|alpha|||false",
+		"mesh.mod.beta.tool.five.anchor||tool|beta|||false",
+		"mesh.mod.beta.tool.four.anchor||tool|beta|||false",
+		"mesh.mod.beta.tool.three.anchor||tool|beta|||false",
+		"mesh.seat.node-shelf.tool.clear.anchor||seat|beta|node-shelf|node|false",
+		"mesh.seat.node-shelf.tool.list.anchor||seat|beta|node-shelf|node|false",
+	}, "\n")
+	if s := subjects(got); s != want {
+		t.Errorf("announced:\n%s\nwant:\n%s", s, want)
+	}
+	for _, e := range got.Endpoints {
+		if e.Metadata["node"] != "anchor" || e.Metadata["description"] == "" {
+			t.Errorf("endpoint metadata: %+v", e)
+		}
+		// A seat's verb carries its schema; a module's tool does not — it outgrew the bus (2026-10-04).
+		_, hasSchema := e.Metadata["schema"]
+		if e.Metadata["kind"] == "seat" && !json.Valid([]byte(e.Metadata["schema"])) {
+			t.Errorf("a seat's verb without a schema: %+v", e)
+		}
+		if e.Metadata["kind"] == "tool" && hasSchema {
+			t.Errorf("a module's tool still announces its schema: %+v", e)
+		}
+	}
+
+	// Every subject announced is answered.
+	asker := connect(t, "console", "workstation")
+	for _, e := range got.Endpoints {
+		if _, err := asker.Ask("", map[string]any{}, e.Subject); err != nil {
+			t.Errorf("announced %s and does not answer it: %v", e.Subject, err)
+		}
+	}
+
+	// PING answers with the same identity, and a request for another service is not answered.
+	if msg, err := nc.Request("$SRV.PING", nil, 2*time.Second); err != nil || !strings.Contains(string(msg.Data), micro.PingResponseType) {
+		t.Errorf("ping: %v %v", msg, err)
+	}
+	if _, err := nc.Request("$SRV.INFO.somebody-else", nil, 300*time.Millisecond); err == nil {
+		t.Error("answered a request for another service")
+	}
+
+	// alpha is re-issued a plain subject: the announcement says so, and says it is interchangeable.
+	mesh.Issue(t, mt.MembershipOf("alpha", "anchor", true, nil))
+	var after string
+	for i := 0; i < 40; i++ {
+		after = subjects(info())
+		if strings.Contains(after, "mesh.mod.alpha.tool.one|serve.alpha|tool|alpha|||true") {
+			break
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	if !strings.Contains(after, "mesh.mod.alpha.tool.one|serve.alpha|tool|alpha|||true") ||
+		!strings.Contains(after, "mesh.mod.alpha.tool.one.anchor||tool|alpha|||true") {
+		t.Errorf("after a re-issued membership:\n%s", after)
+	}
+	_ = bus.Served{}
+}

node-tools/internal/runtime/caller_test.go

@@ -0,0 +1,91 @@
+package runtime
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+type saidCaller struct {
+	Caller    string         `json:"caller"`
+	Arguments map[string]any `json:"arguments"`
+}
+
+// **A module is told who called it, from the subject the call arrived on** (novox/hq issue 365): a call on the
+// caller-named subject reaches the bundle with that caller in the call's `_meta`, for a module's tool, on its
+// machine's address, and for a seat's verb; a caller named in the arguments is only an argument.
+func TestACallOnTheCallerNamedSubjectReachesTheModuleWithItsCaller(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("ledger", "anchor", true, map[string][]string{"node-desk": {"who"}}))
+	nodeTools := connect(t, "node-tools", "anchor")
+	stop, err := Run(nodeTools, []Served{{"ledger", []string{mt.Fixture("caller-echo.py")}}}, nil, func(string, ...any) {})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop() // returns once the bundle's exit is handled (novox/hq issue 476)
+	asker, err := bus.Connect(bus.Credential{URL: mt.URL(t), Module: "node-tools", Node: "shanks",
+		User: "shanks.node-tools", Password: "unused"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	asker.Logf = func(string, ...any) {}
+	defer asker.Close()
+
+	for _, key := range []string{"ledger.who", "ledger.who@anchor", "seat:node-desk.who@anchor"} {
+		var got saidCaller
+		mt.Until(t, func() error {
+			answered, err := asker.Ask(key, map[string]any{"caller": "novox.node-tools",
+				"_meta": map[string]any{"mesh/caller": "novox.controller"}}, "")
+			if err == nil {
+				err = json.Unmarshal(answered.Result, &got)
+			}
+			return err
+		})
+		if got.Caller != "shanks.node-tools" {
+			t.Errorf("%s reached the module with caller %q, want the asker's bus user", key, got.Caller)
+		}
+		if got.Arguments["caller"] != "novox.node-tools" {
+			t.Errorf("%s: the arguments did not reach the module as sent: %v", key, got.Arguments)
+		}
+	}
+}
+
+// The subject that names no caller is still served, for one release (retired by hq issue 464), and says so:
+// the module is named no caller, whatever the body claims.
+func TestTheSubjectThatNamesNoCallerStillWorksAndNamesNone(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("ledger", "anchor", true, map[string][]string{"node-desk": {"who"}}))
+	nodeTools := connect(t, "node-tools", "anchor")
+	stop, err := Run(nodeTools, []Served{{"ledger", []string{mt.Fixture("caller-echo.py")}}}, nil, func(string, ...any) {})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop() // returns once the bundle's exit is handled (novox/hq issue 476)
+	old, err := nats.Connect(mt.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer old.Close()
+	body, _ := json.Marshal(map[string]any{"_meta": map[string]any{"mesh/caller": "novox.controller"}})
+	for _, subject := range []string{"mesh.mod.ledger.tool.who", "mesh.mod.ledger.tool.who.anchor", "mesh.seat.node-desk.tool.who.anchor"} {
+		var reply struct {
+			Result saidCaller `json:"result"`
+			Error  string     `json:"error"`
+		}
+		mt.Until(t, func() error {
+			msg, err := old.Request(subject, body, 5*time.Second)
+			if err == nil {
+				err = json.Unmarshal(msg.Data, &reply)
+			}
+			return err
+		})
+		if reply.Error != "" || reply.Result.Caller != "" {
+			t.Errorf("%s: the module was named caller %q (error %q), want none", subject, reply.Result.Caller, reply.Error)
+		}
+	}
+}

node-tools/internal/runtime/events_test.go

@@ -0,0 +1,157 @@
+package runtime
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/launch"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// A logger safe to write from the runtime's goroutines.
+type lines struct {
+	mu sync.Mutex
+	l  []string
+}
+
+func (s *lines) logf(format string, args ...any) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.l = append(s.l, strings.TrimSpace(sprintf(format, args...)))
+}
+
+func (s *lines) all() string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return strings.Join(s.l, "\n")
+}
+
+func sprintf(format string, args ...any) string { return fmtSprintf(format, args...) }
+
+func countLines(t *testing.T, path, want string) int {
+	t.Helper()
+	b, _ := os.ReadFile(path)
+	n := 0
+	for _, l := range strings.Split(string(b), "\n") {
+		if l == want {
+			n++
+		}
+	}
+	return n
+}
+
+// novox/hq ADR 0198: a module's long-running code is launched by the node's runtime, and the runtime
+// is its bus — it binds the module's own consumer, hands each event to the bundle, and acknowledges it
+// only when the bundle has taken it; one the bundle failed or died on is offered again.
+func TestTheRuntimeHandsAModulesEventsToItsBundleAndAcknowledgesThemOnlyWhenTaken(t *testing.T) {
+	mesh := mt.New(t)
+	restore := bus.NakDelay
+	bus.NakDelay = 300 * time.Millisecond
+	t.Cleanup(func() { bus.NakDelay = restore })
+	firstPause := launch.RestartFirst
+	launch.RestartFirst = 100 * time.Millisecond
+	t.Cleanup(func() { launch.RestartFirst = firstPause })
+
+	mesh.Issue(t, mt.MembershipOf("watcher", "anchor", false, nil))
+	mesh.Issue(t, mt.MembershipOf("beta", "anchor", true, nil))
+	// The controller's consumer for the module, as its own runtime bound it: anchor_watcher on EVENTS.
+	mesh.Consumer(t, "anchor", "watcher", []string{"mesh.mod.alpha.event.>"}, 2*time.Second)
+
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	dir := t.TempDir()
+	log := filepath.Join(dir, "watch.log")
+	said := &lines{}
+	stop, err := Run(nodeTools, []Served{
+		{Module: "watcher", Entrypoints: []string{mt.Fixture("watcher.serve.mjs")}},
+		{Module: "beta", Entrypoints: []string{mt.Fixture("many-beta.serve.mjs")}},
+	}, map[string]map[string]string{"watcher": {"WATCH_LOG": log}}, said.logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	if !strings.Contains(said.all(), "watcher's events arrive on its consumer anchor_watcher") {
+		t.Fatalf("the module's consumer was not bound:\n%s", said.all())
+	}
+
+	// Handled once, acknowledged once.
+	mesh.Emit(t, "mesh.mod.alpha.event.happened", map[string]any{"n": 1})
+	mt.Until(t, func() error {
+		if countLines(t, log, "handled 1") != 1 {
+			return errorf("event 1 not handled yet")
+		}
+		return nil
+	})
+	// The handler fails the first time: not acknowledged, offered again, then handled.
+	mesh.Emit(t, "mesh.mod.alpha.event.happened", map[string]any{"n": 2, "fail": true})
+	// The bundle dies on the first offer: not acknowledged, the bundle is started again and the
+	// event is offered again once its ack wait has passed.
+	mesh.Emit(t, "mesh.mod.alpha.event.happened", map[string]any{"n": 3, "die": true})
+	deadline := time.Now().Add(20 * time.Second)
+	for time.Now().Before(deadline) {
+		if countLines(t, log, "handled 2") == 1 && countLines(t, log, "handled 3") == 1 {
+			break
+		}
+		time.Sleep(200 * time.Millisecond)
+	}
+	if countLines(t, log, "handled 2") != 1 || countLines(t, log, "handled 3") != 1 {
+		b, _ := os.ReadFile(log)
+		t.Fatalf("a failed or interrupted event was not offered again and handled once:\n%s\nruntime:\n%s", b, said.all())
+	}
+	if countLines(t, log, "started") < 2 {
+		t.Errorf("the bundle that died was not started again: %s", said.all())
+	}
+	mt.Until(t, func() error {
+		ack, notYet := mesh.Pending(t, "anchor", "watcher")
+		if ack != 0 || notYet != 0 {
+			return errorf("still pending: %d unacknowledged, %d undelivered", ack, notYet)
+		}
+		return nil
+	})
+	if countLines(t, log, "handled 1") != 1 {
+		t.Errorf("event 1 was handled more than once")
+	}
+
+	// A tool asks another module's tool through the runtime, as the module.
+	got, err := call(t, asker, "watcher.relay@anchor", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"beta":3}`)
+}
+
+// A long-running bundle that exits is started again, without waiting for a call (ADR 0198).
+func TestALongRunningBundleThatExitsIsStartedAgain(t *testing.T) {
+	mesh := mt.New(t)
+	firstPause := launch.RestartFirst
+	launch.RestartFirst = 100 * time.Millisecond
+	t.Cleanup(func() { launch.RestartFirst = firstPause })
+	mesh.Issue(t, mt.MembershipOf("flaky", "anchor", false, nil))
+	nodeTools := connect(t, "node-tools", "anchor")
+	log := filepath.Join(t.TempDir(), "flaky.log")
+	said := &lines{}
+	stop, err := Run(nodeTools, []Served{{Module: "flaky", Entrypoints: []string{mt.Fixture("flaky.serve.mjs")}}},
+		map[string]map[string]string{"flaky": {"FLAKY_LOG": log}}, said.logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	mt.Until(t, func() error {
+		if countLines(t, log, "started") < 3 {
+			return errorf("started %d time(s)", countLines(t, log, "started"))
+		}
+		return nil
+	})
+	if !strings.Contains(said.all(), "flaky's bundle exited (3)") || !strings.Contains(said.all(), "started again in") {
+		t.Errorf("the restart was not said:\n%s", said.all())
+	}
+}
+
+func fmtSprintf(format string, args ...any) string { return fmt.Sprintf(format, args...) }
+func errorf(format string, args ...any) error      { return fmt.Errorf(format, args...) }

node-tools/internal/runtime/log_test.go

@@ -0,0 +1,336 @@
+package runtime
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/launch"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// logBuses is a module, issues, that keeps a log `changes` on a real bus, and a module, other, on the
+// same runtime that was issued no log — each reached as a bundle reaches it: mesh/log.<verb> with its
+// JSON, through its module's bus (novox/hq ADR 0297).
+func logBuses(t *testing.T, maxBytes int64) (issues, other launch.Bus, mesh *mt.Mesh) {
+	t.Helper()
+	mesh = mt.New(t)
+	m := mt.MembershipOf("issues", "anchor", false, nil)
+	m.Logs = []bus.LogIssued{mesh.Log(t, "issues", "changes", maxBytes)}
+	mesh.Issue(t, m)
+	mesh.Issue(t, mt.MembershipOf("other", "anchor", false, nil))
+	conn := connect(t, "node-tools", "anchor")
+	conn.Follow("issues")
+	conn.Follow("other")
+	mt.Until(t, func() error {
+		if conn.Membership("issues") == nil || conn.Membership("other") == nil {
+			return errors.New("not issued yet")
+		}
+		return nil
+	})
+	all := &consumers{conn: conn, logf: t.Logf, of: map[string]*moduleEvents{}}
+	return all.forModule("issues"), all.forModule("other"), mesh
+}
+
+// logAsk is a bundle's mesh/log.<verb>, with its params exactly as they go over the wire.
+func logAsk(b launch.Bus, verb, params string) (json.RawMessage, error) {
+	return b.Log(verb, json.RawMessage(params))
+}
+
+func appendOf(t *testing.T, b launch.Bus, params string) uint64 {
+	t.Helper()
+	raw, err := logAsk(b, "append", params)
+	if err != nil {
+		t.Fatalf("append %s: %v", params, err)
+	}
+	var r struct {
+		Sequence *uint64 `json:"sequence"`
+	}
+	if err := json.Unmarshal(raw, &r); err != nil || r.Sequence == nil {
+		t.Fatalf("append answered %s, not {sequence}", raw)
+	}
+	return *r.Sequence
+}
+
+// wirePage is a read's answer with exactly the contract's field names.
+type wirePage struct {
+	Entries []struct {
+		Sequence uint64          `json:"sequence"`
+		Key      string          `json:"key"`
+		Value    json.RawMessage `json:"value"`
+		At       string          `json:"at"`
+	} `json:"entries"`
+	Next uint64 `json:"next"`
+	Last uint64 `json:"last"`
+}
+
+func readOf(t *testing.T, b launch.Bus, params string) wirePage {
+	t.Helper()
+	raw, err := logAsk(b, "read", params)
+	if err != nil {
+		t.Fatalf("read %s: %v", params, err)
+	}
+	var fields map[string]json.RawMessage
+	_ = json.Unmarshal(raw, &fields)
+	for _, f := range []string{"entries", "next", "last"} {
+		if _, ok := fields[f]; !ok {
+			t.Fatalf("read answered %s, without %q", raw, f)
+		}
+	}
+	var p wirePage
+	if err := json.Unmarshal(raw, &p); err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
+
+func infoOf(t *testing.T, b launch.Bus) map[string]uint64 {
+	t.Helper()
+	raw, err := logAsk(b, "info", `{"log":"changes"}`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var info map[string]uint64
+	if err := json.Unmarshal(raw, &info); err != nil {
+		t.Fatalf("info answered %s: %v", raw, err)
+	}
+	for _, f := range []string{"entries", "bytes", "max_bytes", "first", "last"} {
+		if _, ok := info[f]; !ok {
+			t.Fatalf("info answered %s, without %q", raw, f)
+		}
+	}
+	return info
+}
+
+// Each verb against a real bus: append answers the sequence, read pages from a sequence on, of a key
+// pattern, with the sequence to continue from (0 at the end) and the log's last, each entry's time in
+// RFC 3339; last is a key's last entry or null; info says entries, bytes, cap, first and last — and no
+// consumer is made for any of it.
+func TestALogAnswersEachVerbOnTheBus(t *testing.T) {
+	b, _, mesh := logBuses(t, 1<<20)
+	before := time.Now().Add(-time.Second)
+
+	var seqs []uint64
+	for i, key := range []string{"12", "13", "12", "14.notes", "12"} {
+		seqs = append(seqs, appendOf(t, b, fmt.Sprintf(`{"log":"changes","key":%q,"value":{"op":"move","n":%d}}`, key, i)))
+	}
+	for i := 1; i < len(seqs); i++ {
+		if seqs[i] != seqs[i-1]+1 {
+			t.Fatalf("sequences %v are not the log's order", seqs)
+		}
+	}
+
+	// Everything, no keys and no limit: the default page holds all five.
+	all := readOf(t, b, `{"log":"changes","from":0}`)
+	if len(all.Entries) != 5 || all.Next != 0 || all.Last != seqs[4] {
+		t.Fatalf("a read of everything: %d entries, next %d, last %d", len(all.Entries), all.Next, all.Last)
+	}
+	for i, e := range all.Entries {
+		at, err := time.Parse(time.RFC3339, e.At)
+		if err != nil || at.Before(before) || at.After(time.Now().Add(time.Second)) {
+			t.Errorf("entry %d's time %q is not RFC 3339 and now: %v", e.Sequence, e.At, err)
+		}
+		if e.Sequence != seqs[i] || string(e.Value) != fmt.Sprintf(`{"op":"move","n":%d}`, i) {
+			t.Errorf("entry %d: %d %s %s", i, e.Sequence, e.Key, e.Value)
+		}
+	}
+	if all.Entries[3].Key != "14.notes" {
+		t.Errorf("a key of two names read back as %q", all.Entries[3].Key)
+	}
+
+	// One key's entries, a page of two at a time.
+	first := readOf(t, b, `{"log":"changes","from":1,"keys":"12","limit":2}`)
+	if len(first.Entries) != 2 || first.Entries[0].Sequence != seqs[0] || first.Entries[1].Sequence != seqs[2] ||
+		first.Next != seqs[2]+1 {
+		t.Fatalf("the first page of key 12: %+v", first)
+	}
+	second := readOf(t, b, fmt.Sprintf(`{"log":"changes","from":%d,"keys":"12","limit":2}`, first.Next))
+	if len(second.Entries) != 1 || second.Entries[0].Sequence != seqs[4] || second.Next != 0 {
+		t.Fatalf("the second page of key 12: %+v", second)
+	}
+	// A pattern: `*` one name, `>` the rest.
+	if p := readOf(t, b, `{"log":"changes","from":1,"keys":"14.*"}`); len(p.Entries) != 1 || p.Entries[0].Key != "14.notes" {
+		t.Fatalf("14.*: %+v", p)
+	}
+	if p := readOf(t, b, `{"log":"changes","from":1,"keys":"14.>"}`); len(p.Entries) != 1 {
+		t.Fatalf("14.>: %+v", p)
+	}
+	// Past the end: nothing, nothing follows.
+	if p := readOf(t, b, fmt.Sprintf(`{"log":"changes","from":%d}`, seqs[4]+1)); len(p.Entries) != 0 || p.Next != 0 || p.Last != seqs[4] {
+		t.Fatalf("a read past the end: %+v", p)
+	}
+	if p := readOf(t, b, `{"log":"changes","from":1,"keys":"99"}`); len(p.Entries) != 0 || p.Next != 0 {
+		t.Fatalf("a key with no entries: %+v", p)
+	}
+
+	raw, err := logAsk(b, "last", `{"log":"changes","key":"12"}`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var last map[string]json.RawMessage
+	_ = json.Unmarshal(raw, &last)
+	if string(last["sequence"]) != fmt.Sprint(seqs[4]) || string(last["key"]) != `"12"` ||
+		string(last["value"]) != `{"op":"move","n":4}` || len(last["at"]) == 0 {
+		t.Fatalf("the last entry of 12: %s", raw)
+	}
+	if raw, err := logAsk(b, "last", `{"log":"changes","key":"99"}`); err != nil || string(raw) != "null" {
+		t.Fatalf("the last entry of a key with none: %s %v", raw, err)
+	}
+
+	info := infoOf(t, b)
+	if info["entries"] != 5 || info["first"] != seqs[0] || info["last"] != seqs[4] || info["max_bytes"] != 1<<20 ||
+		info["bytes"] == 0 {
+		t.Fatalf("info: %v", info)
+	}
+	if n := mesh.Consumers(t, "LOG_issues_changes"); n != 0 {
+		t.Fatalf("the runtime made %d consumers of the log; it uses none", n)
+	}
+}
+
+// A page holds about 4 MiB at most, whatever its limit, and says where to continue.
+func TestALogPageIsBoundedByItsBytes(t *testing.T) {
+	b, _, _ := logBuses(t, 64<<20)
+	big := `"` + strings.Repeat("x", 250*1024) + `"`
+	for i := 0; i < 20; i++ {
+		appendOf(t, b, fmt.Sprintf(`{"log":"changes","key":"k%d","value":%s}`, i, big))
+	}
+	p := readOf(t, b, `{"log":"changes","from":1,"limit":1000}`)
+	if len(p.Entries) == 0 || len(p.Entries) >= 20 || p.Next != p.Entries[len(p.Entries)-1].Sequence+1 {
+		t.Fatalf("a page of 20 entries of 250 KiB: %d entries, next %d", len(p.Entries), p.Next)
+	}
+	got := len(p.Entries)
+	for p.Next != 0 {
+		p = readOf(t, b, fmt.Sprintf(`{"log":"changes","from":%d,"limit":1000}`, p.Next))
+		got += len(p.Entries)
+	}
+	if got != 20 {
+		t.Fatalf("paging read %d of 20 entries", got)
+	}
+}
+
+// An append with `expect` is written only when the key's last entry is the one expected — 0 when it
+// has none — and is otherwise refused with the error a lost mesh/state.update answers: the same code,
+// the same error, and nothing written. An append without `expect` is not checked.
+func TestAnAppendAtAStaleExpectIsRefusedAsALostUpdate(t *testing.T) {
+	b, _, _ := logBuses(t, 1<<20)
+	isLost := func(err error) bool {
+		var coded interface{ ErrorCode() int }
+		return errors.As(err, &coded) && coded.ErrorCode() == launch.CodeChanged && errors.Is(err, bus.ErrStateChanged)
+	}
+
+	first := appendOf(t, b, `{"log":"changes","key":"7","value":{"op":"open"},"expect":0}`)
+	if _, err := logAsk(b, "append", `{"log":"changes","key":"7","value":{"op":"open"},"expect":0}`); !isLost(err) {
+		t.Fatalf("a second open of one key at expect 0: %v", err)
+	}
+	second := appendOf(t, b, fmt.Sprintf(`{"log":"changes","key":"7","value":{"op":"move"},"expect":%d}`, first))
+	if _, err := logAsk(b, "append", fmt.Sprintf(`{"log":"changes","key":"7","value":{"op":"note"},"expect":%d}`, first)); !isLost(err) {
+		t.Fatalf("an append at a stale expect: %v", err)
+	}
+	if _, err := logAsk(b, "append", fmt.Sprintf(`{"log":"changes","key":"7","value":{"op":"note"},"expect":%d}`, second+100)); !isLost(err) {
+		t.Fatalf("an append at an expect not yet written: %v", err)
+	}
+	// Another key's entries do not make this key's expect stale.
+	appendOf(t, b, `{"log":"changes","key":"8","value":{"op":"open"}}`)
+	third := appendOf(t, b, fmt.Sprintf(`{"log":"changes","key":"7","value":{"op":"note"},"expect":%d}`, second))
+	// No expect: no check.
+	appendOf(t, b, `{"log":"changes","key":"7","value":{"op":"set"}}`)
+
+	if info := infoOf(t, b); info["entries"] != 5 {
+		t.Fatalf("refused appends wrote: %d entries, not 5", info["entries"])
+	}
+	p := readOf(t, b, `{"log":"changes","from":1,"keys":"7"}`)
+	if len(p.Entries) != 4 || p.Entries[2].Sequence != third {
+		t.Fatalf("key 7 holds %+v", p.Entries)
+	}
+
+	// The refusal is the very error a lost state update is: its code reaches a bundle as CodeChanged.
+	_, err := logAsk(b, "append", `{"log":"changes","key":"7","value":{},"expect":0}`)
+	var coded interface{ ErrorCode() int }
+	if !errors.As(err, &coded) || coded.ErrorCode() != -32010 {
+		t.Fatalf("the refusal carries no lost-update code: %v", err)
+	}
+}
+
+// A log is its owner's alone: another module on the same runtime is refused it with the reason, and so
+// is a log of a name the owner was not issued — before anything is sent.
+func TestALogNotIssuedIsRefusedWithTheReason(t *testing.T) {
+	issues, other, _ := logBuses(t, 1<<20)
+	for verb, params := range map[string]string{
+		"append": `{"log":"changes","key":"1","value":{}}`,
+		"read":   `{"log":"changes","from":1}`,
+		"last":   `{"log":"changes","key":"1"}`,
+		"info":   `{"log":"changes"}`,
+	} {
+		_, err := logAsk(other, verb, params)
+		if err == nil || !strings.Contains(err.Error(), `other keeps no log called "changes"`) ||
+			!strings.Contains(err.Error(), "issued: none") {
+			t.Errorf("%s of a log not issued: %v", verb, err)
+		}
+	}
+	_, err := logAsk(issues, "append", `{"log":"moves","key":"1","value":{}}`)
+	if err == nil || !strings.Contains(err.Error(), `issues keeps no log called "moves"`) ||
+		!strings.Contains(err.Error(), "issued: changes") {
+		t.Errorf("an append to a log of a name not issued: %v", err)
+	}
+	if info := infoOf(t, issues); info["entries"] != 0 {
+		t.Fatalf("a refused append wrote: %v", info)
+	}
+}
+
+// What the bus cannot hold, or the contract does not allow, is refused with the reason and not sent:
+// a value that is not JSON or over 256 KiB, a key that is not names joined by dots or over 255 bytes, a
+// key pattern with `>` not last, a limit over 1000.
+func TestWhatALogCannotHoldIsRefusedWithTheReason(t *testing.T) {
+	b, _, _ := logBuses(t, 1<<20)
+	over := `"` + strings.Repeat("x", 256*1024) + `"`
+	for params, reason := range map[string]string{
+		`{"log":"changes","key":"1","value":nope}`:                             "names no log",
+		`{"log":"changes","key":"1"}`:                                          "is JSON",
+		`{"log":"changes","key":"1","value":` + over + `}`:                     "at most 262144 bytes",
+		`{"log":"changes","key":"a b","value":1}`:                              "is not a log key",
+		`{"log":"changes","key":"a..b","value":1}`:                             "is not a log key",
+		`{"log":"changes","key":"a.*","value":1}`:                              "is not a log key",
+		`{"log":"changes","key":"` + strings.Repeat("k", 256) + `","value":1}`: "is not a log key",
+		`{"key":"1","value":1}`:                                                "names no log",
+	} {
+		if _, err := logAsk(b, "append", params); err == nil || !strings.Contains(err.Error(), reason) {
+			t.Errorf("append %.80s: %v, want %q", params, err, reason)
+		}
+	}
+	for params, reason := range map[string]string{
+		`{"log":"changes","from":1,"keys":"a.>.b"}`: "is not a key pattern",
+		`{"log":"changes","from":1,"limit":1001}`:   "1 to 1000",
+		`{"log":"changes","from":1,"limit":-1}`:     "1 to 1000",
+	} {
+		if _, err := logAsk(b, "read", params); err == nil || !strings.Contains(err.Error(), reason) {
+			t.Errorf("read %s: %v, want %q", params, err, reason)
+		}
+	}
+	if info := infoOf(t, b); info["entries"] != 0 {
+		t.Fatalf("a refused append wrote: %v", info)
+	}
+	// The largest value allowed is taken, also with the header an expect carries.
+	largest := `"` + strings.Repeat("x", 256*1024-2) + `"`
+	appendOf(t, b, `{"log":"changes","key":"1","value":`+largest+`,"expect":0}`)
+	appendOf(t, b, `{"log":"changes","key":"2","value":`+largest+`}`)
+}
+
+// A value naming a credential anywhere in it is refused, as mesh/state.put refuses one (novox/hq ADR
+// 0201 §13): a log keeps what it is given for good. A value that only counts tokens is taken.
+func TestALogRefusesAValueNamingACredential(t *testing.T) {
+	b, _, _ := logBuses(t, 1<<20)
+	for _, value := range []string{`{"op":"set","api_key":"s"}`, `{"op":"note","with":{"headers":{"Authorization":"Bearer s"}}}`} {
+		_, err := logAsk(b, "append", `{"log":"changes","key":"1","value":`+value+`}`)
+		if err == nil || !strings.Contains(err.Error(), "names a credential") {
+			t.Errorf("append of %s: %v", value, err)
+		}
+	}
+	if info := infoOf(t, b); info["entries"] != 0 {
+		t.Fatalf("a refused append wrote: %v", info)
+	}
+	appendOf(t, b, `{"log":"changes","key":"1","value":{"op":"note","maxTokens":4096}}`)
+}

node-tools/internal/runtime/own_account_test.go

@@ -0,0 +1,56 @@
+package runtime
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// novox/hq ADR 0259 §8: a runtime on a module's own account serves that module alone, and the machine's
+// runtime never serves itself.
+func TestARuntimeOnAModulesOwnAccountServesThatModuleAlone(t *testing.T) {
+	if got, err := ServedModulesFrom("telegram=/b/telegram/tools/telegram", "telegram"); err != nil || len(got) != 1 {
+		t.Fatalf("a module's own runtime could not serve it: %v", err)
+	}
+	if _, err := ServedModulesFrom("telegram=/b/t,dunst=/b/d", "telegram"); err == nil || !strings.Contains(err.Error(), "serves telegram alone") {
+		t.Errorf("a module's own runtime served another: %v", err)
+	}
+	if _, err := ServedModulesFrom("node-tools=/b/n", "node-tools"); err == nil {
+		t.Error("the machine's runtime served itself")
+	}
+}
+
+// No bus word reaches a bundle (security review of 2026-10-08), not even one its module's words name.
+func TestNoBusWordReachesABundle(t *testing.T) {
+	base := []string{"MESH_BROKER_FILE=/etc/mesh/broker", "MESH_BROKER_URL=nats://x", "MESH_TOOL_ENV={}",
+		"MESH_TOOL_MODULES=a=/b", "MESH_CONSOLE_LISTEN=127.0.0.1:1", "PATH=/usr/bin"}
+	env := strings.Join(BundleEnv(base, map[string]string{"MESH_BROKER_FILE": "/again", "OWN": "1"}, "telegram", "anchor"), "\n")
+	for _, never := range []string{"MESH_BROKER_FILE", "MESH_BROKER_URL", "MESH_TOOL_ENV", "MESH_TOOL_MODULES", "MESH_CONSOLE_LISTEN"} {
+		if strings.Contains(env, never+"=") {
+			t.Errorf("%s reached the bundle", never)
+		}
+	}
+	for _, want := range []string{"PATH=/usr/bin", "OWN=1", "MESH_MODULE=telegram", "MESH_NODE=anchor"} {
+		if !strings.Contains(env, want) {
+			t.Errorf("%s did not reach the bundle", want)
+		}
+	}
+}
+
+// A tool call reaches only a tool's subject: whatever key a caller names, it is never a seat's event, accept
+// or proof — so no tool call says a choice, a link or a code, or submits an ask, in anybody's name.
+func TestAToolCallNeverReachesASeatsEventAcceptOrProof(t *testing.T) {
+	for _, key := range []string{"seat:intake.event.choice.telegram", "seat:intake.proof.code.telegram",
+		"seat:operator-channel.accept.ask.mesh-delivery", "intake.event", "seat:operator-channel.event.decided.x@anchor",
+		"telegram.anything", "x"} {
+		subject, err := bus.ToolSubject(key, "node-tools")
+		if err != nil {
+			continue
+		}
+		tokens := strings.Split(subject, ".")
+		if len(tokens) < 4 || tokens[3] != "tool" {
+			t.Errorf("%q reaches %s, which is not a tool's subject", key, subject)
+		}
+	}
+}

node-tools/internal/runtime/runtime.go

@@ -0,0 +1,870 @@
+// Package runtime is the node's tool runtime (novox/hq ADR 0175, ADR 0193), the Go port of
+// node-tools' runtime.ts in its launch-only form: it launches every assigned module's bundle,
+// serves each module's tools on that module's subjects and each held seat's verbs on the seat's,
+// and answers for every module the verb that says what it serves. It imports nothing and knows no
+// language.
+package runtime
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/launch"
+)
+
+// ToolsVerb is the verb every module's runtime answers for it (ADR 0152): its tools, from the code
+// that answers them.
+const ToolsVerb = "tools"
+
+// Words the mesh sets for the runtime (ADR 0175, ADR 0192).
+const (
+	ToolModules     = "MESH_TOOL_MODULES"
+	ToolEnv         = "MESH_TOOL_ENV"
+	OperatorAccount = "MESH_OPERATOR_ACCOUNT"
+	OperatorHome    = "MESH_OPERATOR_HOME"
+)
+
+// Served is one module this runtime serves and its entrypoints.
+type Served struct {
+	Module      string
+	Entrypoints []string
+}
+
+// ToolsAnswer is what `tools` answers for one module.
+type ToolsAnswer struct {
+	Module string       `json:"module"`
+	Tools  []ListedTool `json:"tools"`
+	Failed string       `json:"failed,omitempty"`
+}
+
+// ListedTool is one tool as a module's `tools` answer lists it.
+type ListedTool struct {
+	Name        string          `json:"name"`
+	Description string          `json:"description"`
+	Input       json.RawMessage `json:"input"`
+	Subjects    []string        `json:"subjects,omitempty"`
+}
+
+// NodeRuntimeModule is the module that is a machine's runtime, serving every module on it.
+const NodeRuntimeModule = "node-tools"
+
+// runtimeOnly are the words of the runtime's own environment no bundle is given.
+var runtimeOnly = map[string]bool{ToolEnv: true, ToolModules: true, "MESH_BROKER_FILE": true,
+	"MESH_BROKER_URL": true, "MESH_CONSOLE_LISTEN": true}
+
+// ServedModulesFrom reads MESH_TOOL_MODULES: `<module>=<entrypoint>` entries, comma-separated, several
+// per module. The one-module form — a bare path, or the runtime's own module — is the per-module
+// containers' (to-be 38 WP4c) and refused here: the node's runtime imports nothing.
+func ServedModulesFrom(spec, own string) ([]Served, error) {
+	order := []string{}
+	by := map[string][]string{}
+	for _, raw := range strings.Split(spec, ",") {
+		entry := strings.TrimSpace(raw)
+		if entry == "" {
+			continue
+		}
+		module, path, ok := strings.Cut(entry, "=")
+		module, path = strings.TrimSpace(module), strings.TrimSpace(path)
+		if !ok || module == "" || path == "" {
+			return nil, fmt.Errorf("%s: %q is not <module>=<entrypoint>; the runtime launches the bundles it "+
+				"is given and imports nothing (novox/hq ADR 0193)", ToolModules, entry)
+		}
+		// The node's runtime serves the machine's modules and never itself. **A runtime on a module's own
+		// account serves that module and nothing else** (novox/hq ADR 0259 §8): the router and a channel that
+		// proves its sender reach the bus on an account of their own, never the machine's runtime.
+		switch {
+		case own == NodeRuntimeModule && module == own:
+			return nil, fmt.Errorf("%s: %q is the runtime itself; it launches the bundles it is given and "+
+				"imports nothing (novox/hq ADR 0193)", ToolModules, entry)
+		case own != NodeRuntimeModule && module != own:
+			return nil, fmt.Errorf("%s: %q is another module's; a runtime on %s's own account serves %s alone "+
+				"(novox/hq ADR 0259)", ToolModules, entry, own, own)
+		}
+		if _, seen := by[module]; !seen {
+			order = append(order, module)
+		}
+		by[module] = append(by[module], path)
+	}
+	out := make([]Served, 0, len(order))
+	for _, m := range order {
+		out = append(out, Served{Module: m, Entrypoints: by[m]})
+	}
+	return out, nil
+}
+
+// TakeToolEnvs reads the composed environments (ADR 0192) and removes them from the process's, so no
+// bundle finds another's there.
+func TakeToolEnvs() (map[string]map[string]string, error) {
+	raw := os.Getenv(ToolEnv)
+	os.Unsetenv(ToolEnv)
+	out := map[string]map[string]string{}
+	if raw == "" {
+		return out, nil
+	}
+	var parsed map[string]map[string]any
+	if err := json.Unmarshal([]byte(raw), &parsed); err != nil {
+		return nil, fmt.Errorf(`%s is not JSON of the shape {"<module>": {"<word>": "<value>"}}: %w`, ToolEnv, err)
+	}
+	for module, words := range parsed {
+		own := map[string]string{}
+		for k, v := range words {
+			if s, ok := v.(string); ok {
+				own[k] = s
+			} else {
+				b, _ := json.Marshal(v)
+				own[k] = string(b)
+			}
+		}
+		out[module] = own
+	}
+	return out, nil
+}
+
+type registration struct {
+	module string // the module's own name, or a seat's
+	owner  string // the module whose bundle made it
+	tools  []launch.Tool
+}
+
+// Run launches, binds and serves. It answers a stop function.
+func Run(conn *bus.Conn, served []Served, envs map[string]map[string]string, logf func(string, ...any)) (func(), error) {
+	if account := os.Getenv(OperatorAccount); account != "" {
+		home := ""
+		if h := os.Getenv(OperatorHome); h != "" {
+			home = " (home " + h + ")"
+		}
+		logf("[mesh-tools] the operator's account here is %s%s", account, home)
+	}
+	modules := make([]string, 0, len(served))
+	isServed := map[string]bool{}
+	for _, s := range served {
+		modules = append(modules, s.Module)
+		isServed[s.Module] = true
+		conn.Follow(s.Module)
+	}
+	node := conn.Node()
+
+	base := os.Environ()
+	envFor := func(module string) []string { return BundleEnv(base, envs[module], module, node) }
+
+	// The module's events, for every child of it that subscribes (ADR 0198): one consumer per module,
+	// bound the first time any of its children subscribes, each event handed to every child that did.
+	events := &consumers{conn: conn, logf: logf, of: map[string]*moduleEvents{}}
+
+	failed := map[string]string{}
+	var registrations []registration
+	var stops []func()
+	for _, s := range served {
+		for _, entry := range s.Entrypoints {
+			path, _ := filepath.Abs(entry)
+			module := s.Module
+			fail := func(why string) {
+				failed[module] = why
+				logf("[mesh-tools] %s's bundle %s failed to load: %s; its tools are not served here", module, entry, why)
+			}
+			if !launch.Executable(path) {
+				fail(path + " is not executable; a bundle the runtime serves is started, never imported, and its build makes it executable (novox/hq ADR 0193)")
+				continue
+			}
+			child, err := launch.Start(module, path, envFor(module), events.forModule(module), logf)
+			if err != nil {
+				fail(err.Error())
+				continue
+			}
+			stops = append(stops, child.Stop)
+			for _, r := range child.Registrations {
+				registrations = append(registrations, registration{module: r.Module, owner: module, tools: r.Tools})
+			}
+		}
+	}
+
+	claimed := map[string]bool{}
+	for _, m := range modules {
+		if mem := conn.Membership(m); mem != nil {
+			for _, s := range mem.Seats {
+				claimed[s.Seat] = true
+			}
+		}
+	}
+	var own []registration
+	for _, r := range registrations {
+		switch {
+		case isServed[r.module]:
+			own = append(own, r)
+		case claimed[r.module]:
+		default:
+			logf(`[mesh-tools] %s registers tools under "%s", which is neither a module served here nor a seat one of them claims; not served until the mesh issues the claim`, r.owner, r.module)
+		}
+	}
+	stopAll := func() {
+		events.stopAll()
+		for i := len(stops) - 1; i >= 0; i-- {
+			stops[i]()
+		}
+	}
+	for _, r := range own {
+		seen := map[string]bool{}
+		for _, t := range r.tools {
+			if t.Name == ToolsVerb {
+				stopAll()
+				return nil, fmt.Errorf(`%s names a tool "%s", which is the verb the runtime answers for every module with what it serves (novox/hq ADR 0152) — refused, rename it`, r.module, ToolsVerb)
+			}
+			if seen[t.Name] {
+				stopAll()
+				return nil, fmt.Errorf("%s exposes two tools named %s — refused", r.module, t.Name)
+			}
+			seen[t.Name] = true
+		}
+	}
+
+	var names []string
+	byModule := map[string][]launch.Tool{}
+	for _, r := range own {
+		for _, t := range r.tools {
+			t := t
+			// Told who called, from the subject the call arrived on, never from its body (novox/hq issue 365).
+			stop, err := conn.HandleCalled(r.module+"."+t.Name, func(caller string, body json.RawMessage) (any, error) {
+				return t.Run(caller, argsOf(body))
+			})
+			if err != nil {
+				logf("[mesh-tools] cannot serve %s.%s: %v", r.module, t.Name, err)
+				continue
+			}
+			names = append(names, r.module+"."+t.Name)
+			stops = append(stops, stop)
+		}
+		byModule[r.module] = append(byModule[r.module], r.tools...)
+	}
+	for _, module := range modules {
+		module := module
+		tools := byModule[module]
+		why := failed[module]
+		if len(tools) == 0 && why == "" {
+			continue // a pure-events module: silent, as it always was
+		}
+		stop, err := conn.Handle(module+"."+ToolsVerb, func(json.RawMessage) (any, error) {
+			answer := ToolsAnswer{Module: module, Tools: []ListedTool{}, Failed: why}
+			for _, t := range tools {
+				answer.Tools = append(answer.Tools, ListedTool{Name: t.Name, Description: t.Description,
+					Input: t.Input, Subjects: subjectsOf(conn, module, t.Name)})
+			}
+			return answer, nil
+		})
+		if err == nil {
+			stops = append(stops, stop)
+		}
+	}
+
+	failedNames := make([]string, 0, len(failed))
+	for _, m := range modules {
+		if _, f := failed[m]; f {
+			failedNames = append(failedNames, m)
+		}
+	}
+	line := fmt.Sprintf("[mesh-tools] serving %d tool(s) for %d module(s): %s", len(names), len(modules), orNone(names))
+	if len(failedNames) > 0 {
+		line += fmt.Sprintf("; not serving %s, whose bundle(s) failed to load", strings.Join(failedNames, ", "))
+	}
+	logf("%s", line)
+	stops = append(stops, serveSeats(conn, modules, registrations, logf))
+
+	// **What it serves, it announces** (novox/hq ADR 0197): the NATS services protocol's discovery,
+	// answered with what is served at the moment it is asked — re-served memberships included.
+	announced, err := announce.Serve(conn, announce.Service{
+		Name: conn.Module(), ID: instanceOf(conn),
+		Description: "the mesh's tool runtime on " + node + ": every assigned module's tools and the seats they hold",
+		Metadata:    map[string]string{"node": node},
+	}, func() []announce.Endpoint { return endpointsOf(conn, own, registrations, modules) })
+	if err != nil {
+		logf("[mesh-tools] cannot announce what it serves: %v", err)
+	} else {
+		stops = append(stops, announced)
+	}
+	conn.Flush()
+	return stopAll, nil
+}
+
+// instanceOf is this runtime's instance on the bus: its machine, which is what tells two instances of
+// one service apart; the connection's module where it has no machine.
+func instanceOf(conn *bus.Conn) string {
+	if n := conn.Node(); n != "" {
+		return n
+	}
+	return conn.Module()
+}
+
+// endpointsOf is everything this runtime serves now: each served module's tools on every subject the
+// mesh issued for them, and each held seat's verbs on the seat's subject (ADR 0197).
+func endpointsOf(conn *bus.Conn, own []registration, registrations []registration, modules []string) []announce.Endpoint {
+	node := conn.Node()
+	var out []announce.Endpoint
+	for _, r := range own {
+		for _, t := range r.tools {
+			served := conn.ServedOn(r.module, t.Name)
+			interchangeable := false
+			for _, s := range served {
+				interchangeable = interchangeable || s.Subject == "mesh.mod."+r.module+".tool."+t.Name
+			}
+			for _, s := range served {
+				out = append(out, announce.Endpoint{Kind: announce.KindTool, Module: r.module, Tool: t.Name,
+					Node: node, Description: t.Description, Schema: t.Input, Interchangeable: interchangeable,
+					Subject: s.Subject, Queue: s.Queue})
+			}
+		}
+	}
+	impl := map[string]map[string]launch.Tool{}
+	for _, r := range registrations {
+		if impl[r.module] == nil {
+			impl[r.module] = map[string]launch.Tool{}
+		}
+		for _, t := range r.tools {
+			impl[r.module][t.Name] = t
+		}
+	}
+	have := map[string]bool{}
+	for _, module := range modules {
+		m := conn.Membership(module)
+		if m == nil {
+			continue
+		}
+		for _, v := range m.Seats {
+			t, ok := impl[v.Seat][v.Verb]
+			if !ok || have[v.Subject] {
+				continue
+			}
+			have[v.Subject] = true
+			scope := "mesh"
+			if node != "" && strings.HasSuffix(v.Subject, "."+node) {
+				scope = "node"
+			}
+			out = append(out, announce.Endpoint{Kind: announce.KindSeat, Module: module, Tool: v.Verb, Seat: v.Seat,
+				Scope: scope, Node: node, Description: t.Description, Schema: t.Input, Subject: v.Subject})
+		}
+	}
+	return out
+}
+
+func orNone(names []string) string {
+	if len(names) == 0 {
+		return "(none)"
+	}
+	return strings.Join(names, ", ")
+}
+
+// argsOf is a call's arguments as the tool receives them: an object, `{}` for none.
+func argsOf(body json.RawMessage) json.RawMessage {
+	trimmed := strings.TrimSpace(string(body))
+	if trimmed == "" || trimmed == "null" {
+		return json.RawMessage("{}")
+	}
+	return body
+}
+
+// subjectsOf is where a tool is answered as the mesh issued it: the plain subject first, then this
+// machine's; nothing before a membership is issued.
+func subjectsOf(conn *bus.Conn, module, tool string) []string {
+	m := conn.Membership(module)
+	if m == nil {
+		return nil
+	}
+	var plain, mine []string
+	for _, s := range m.Serves {
+		subject := strings.ReplaceAll(s.Subject, "{tool}", tool)
+		if s.Queue != "" {
+			plain = append(plain, subject)
+		} else {
+			mine = append(mine, subject)
+		}
+	}
+	return append(plain, mine...)
+}
+
+// serveSeats serves every verb of every seat a served module holds, where the mesh issued it, by
+// the tool of the same name registered under the seat's name (ADR 0159, 0160) — and serves again
+// whenever a membership changes. Whether this machine holds the seat is the bus's to decide.
+func serveSeats(conn *bus.Conn, modules []string, registrations []registration, logf func(string, ...any)) func() {
+	impl := map[string]map[string]launch.Tool{}
+	for _, r := range registrations {
+		if impl[r.module] == nil {
+			impl[r.module] = map[string]launch.Tool{}
+		}
+		for _, t := range r.tools {
+			impl[r.module][t.Name] = t
+		}
+	}
+	var mu sync.Mutex
+	var stops []func()
+	serve := func() {
+		mu.Lock()
+		defer mu.Unlock()
+		for _, s := range stops {
+			s()
+		}
+		stops = nil
+		have := map[string]bool{}
+		for _, module := range modules {
+			m := conn.Membership(module)
+			if m == nil {
+				continue
+			}
+			for _, v := range m.Seats {
+				if have[v.Subject] {
+					continue
+				}
+				have[v.Subject] = true
+				t, ok := impl[v.Seat][v.Verb]
+				if !ok {
+					logf("[mesh-tools] %s claims %s and implements no %s, which that seat promises; not served", module, v.Seat, v.Verb)
+					continue
+				}
+				stop, err := conn.HandleSubjectCalled(v.Subject, func(caller string, body json.RawMessage) (any, error) {
+					return t.Run(caller, argsOf(body))
+				})
+				if err != nil {
+					logf("[mesh-tools] cannot serve %s's %s on %s: %v", v.Seat, v.Verb, v.Subject, err)
+					continue
+				}
+				stops = append(stops, stop)
+				logf("[mesh-tools] serving %s's %s on %s, admitted where %s holds the seat", v.Seat, v.Verb, v.Subject, module)
+			}
+		}
+	}
+	serve()
+	conn.OnMembership(func(bus.Membership) { go func() { serve(); conn.Flush() }() })
+	return func() {
+		mu.Lock()
+		defer mu.Unlock()
+		for _, s := range stops {
+			s()
+		}
+		stops = nil
+	}
+}
+
+// consumers holds, per module the runtime serves, the one durable consumer its events arrive on and
+// the children its events are handed to (novox/hq ADR 0198).
+type consumers struct {
+	conn *bus.Conn
+	logf func(string, ...any)
+	mu   sync.Mutex
+	of   map[string]*moduleEvents
+	// seatBound is each module's seat traffic bound once: a worker taken, a proof subject answered.
+	seatBound map[string]func()
+}
+
+type moduleEvents struct {
+	stop     func()
+	delivers []*func(json.RawMessage) error
+}
+
+// stopAll unbinds every module's consumer.
+func (c *consumers) stopAll() {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for _, m := range c.of {
+		if m.stop != nil {
+			m.stop()
+		}
+	}
+	c.of = map[string]*moduleEvents{}
+	for _, stop := range c.seatBound {
+		stop()
+	}
+	c.seatBound = map[string]func(){}
+}
+
+// forModule is the bus one launched bundle of a module reaches the mesh through.
+func (c *consumers) forModule(module string) launch.Bus {
+	return &moduleBus{all: c, module: module}
+}
+
+type moduleBus struct {
+	all     *consumers
+	module  string
+	mu      sync.Mutex
+	deliver *func(json.RawMessage) error
+}
+
+// Publish emits an event as the module (ADR 0193).
+func (b *moduleBus) Publish(params json.RawMessage) error {
+	var env bus.Envelope
+	if err := json.Unmarshal(params, &env); err != nil {
+		return fmt.Errorf("not an event envelope: %w", err)
+	}
+	return b.all.conn.PublishAs(b.module, env)
+}
+
+// Ask calls a tool as the module: `{key, body}`, answered with the tool's result (ADR 0198).
+func (b *moduleBus) Ask(params json.RawMessage) (json.RawMessage, error) {
+	var asked struct {
+		Key  string          `json:"key"`
+		Body json.RawMessage `json:"body"`
+	}
+	if err := json.Unmarshal(params, &asked); err != nil || asked.Key == "" {
+		return nil, fmt.Errorf("mesh/ask names no tool: {key, body}")
+	}
+	body := any(asked.Body)
+	if len(asked.Body) == 0 {
+		body = map[string]any{}
+	}
+	answered, err := b.all.conn.AskAs(b.module, asked.Key, body)
+	if err != nil {
+		return nil, err
+	}
+	if len(answered.Result) == 0 {
+		return json.RawMessage("null"), nil
+	}
+	return answered.Result, nil
+}
+
+// Subscribe hands this bundle the module's events. The consumer is bound once per module; each of
+// the module's children that subscribed is handed every event, and the event is acknowledged only
+// when all of them took it — one consumer split between two readers would give each half.
+func (b *moduleBus) Subscribe(deliver func(json.RawMessage) error) error {
+	b.mu.Lock()
+	if b.deliver == nil {
+		d := deliver
+		b.deliver = &d
+	} else {
+		*b.deliver = deliver
+	}
+	mine := b.deliver
+	b.mu.Unlock()
+
+	c := b.all
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	m := c.of[b.module]
+	if m == nil {
+		m = &moduleEvents{}
+		c.of[b.module] = m
+	}
+	listed := false
+	for _, d := range m.delivers {
+		if d == mine {
+			listed = true
+		}
+	}
+	if !listed {
+		m.delivers = append(m.delivers, mine)
+	}
+	if m.stop != nil {
+		return nil
+	}
+	module := b.module
+	stop, err := c.conn.ConsumeAs(module, func(env bus.Envelope) error {
+		raw, err := json.Marshal(env)
+		if err != nil {
+			return err
+		}
+		c.mu.Lock()
+		targets := append([]*func(json.RawMessage) error(nil), c.of[module].delivers...)
+		c.mu.Unlock()
+		for _, d := range targets {
+			if err := (*d)(raw); err != nil {
+				c.logf("[mesh-tools] %s did not take %s%s: %s; offered again in %s", module, env.Key,
+					eventRef(env), whyNotTaken(err), bus.NakDelay)
+				return err
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	m.stop = stop
+	c.logf("[mesh-tools] %s's events arrive on its consumer %s", module, bus.ConsumerOf(c.conn.Node(), module))
+	return nil
+}
+
+// whyNotTaken says why a bundle did not take an event, so the line names who failed: the module's
+// handler, in its own words — an error it answered — or the runtime not reaching it. A bundle's
+// handler error read bare ("Unexpected end of JSON input") looked like the runtime's (issue 276).
+func whyNotTaken(err error) string {
+	var refused *launch.Refused
+	if errors.As(err, &refused) {
+		return fmt.Sprintf("its handler answered an error, in its own words: %q (an event is taken by any answer that is not an error)", refused.Message)
+	}
+	return err.Error()
+}
+
+// eventRef names the event a line is about by its id, when it has one, so its offers can be told
+// apart from another event's.
+func eventRef(env bus.Envelope) string {
+	if id := env.Headers["x-event-id"]; id != "" {
+		return " (event " + id + ")"
+	}
+	return ""
+}
+
+// stateAsked is what a bundle names when it reaches its state (ADR 0201): the state by the name its
+// module uses, a key, and for a put the value.
+type stateAsked struct {
+	State    string          `json:"state"`
+	Key      string          `json:"key"`
+	Value    json.RawMessage `json:"value"`
+	Revision uint64          `json:"revision"`
+}
+
+// State answers a bundle's `get`, `put`, `delete`, `keys`, `create`, `update` and `history` on its
+// module's state (ADR 0201, ADR 0259, ADR 0307). The runtime refuses, with the reason, a state the module was not issued and a write to one it only reads.
+func (b *moduleBus) State(verb string, params json.RawMessage) (json.RawMessage, error) {
+	var asked stateAsked
+	if err := json.Unmarshal(params, &asked); err != nil || asked.State == "" {
+		return nil, fmt.Errorf("mesh/state.%s names no state: {state, key, value}", verb)
+	}
+	conn := b.all.conn
+	var answer any
+	switch verb {
+	case "get":
+		entry, err := conn.StateGet(b.module, asked.State, asked.Key)
+		if err != nil {
+			return nil, err
+		}
+		if entry == nil {
+			return json.RawMessage("null"), nil
+		}
+		answer = entry
+	case "history":
+		// Every value the bucket still keeps for the key, oldest first (novox/hq ADR 0307).
+		kept, err := conn.StateHistory(b.module, asked.State, asked.Key)
+		if err != nil {
+			return nil, err
+		}
+		answer = kept
+	case "put":
+		revision, err := conn.StatePut(b.module, asked.State, asked.Key, asked.Value)
+		if err != nil {
+			return nil, err
+		}
+		answer = map[string]any{"revision": revision}
+	case "delete":
+		if err := conn.StateDelete(b.module, asked.State, asked.Key); err != nil {
+			return nil, err
+		}
+		answer = map[string]any{}
+	case "keys":
+		keys, err := conn.StateKeys(b.module, asked.State)
+		if err != nil {
+			return nil, err
+		}
+		answer = keys
+	case "create":
+		// Only when the key has no value: of two writers making it, one wins (novox/hq ADR 0259).
+		revision, err := conn.StateCreate(b.module, asked.State, asked.Key, asked.Value)
+		if err != nil {
+			return nil, err
+		}
+		answer = map[string]any{"revision": revision}
+	case "update":
+		// Only when the key is still at the revision read: a second answer to one ask loses (ADR 0259).
+		revision, err := conn.StateUpdate(b.module, asked.State, asked.Key, asked.Value, asked.Revision)
+		if err != nil {
+			return nil, err
+		}
+		answer = map[string]any{"revision": revision}
+	default:
+		return nil, fmt.Errorf("the runtime answers no mesh/state.%s", verb)
+	}
+	return json.Marshal(answer)
+}
+
+// logAsked is what a bundle names when it reaches its log (novox/hq ADR 0297).
+type logAsked struct {
+	Log    string          `json:"log"`
+	Key    string          `json:"key"`
+	Value  json.RawMessage `json:"value"`
+	Expect *uint64         `json:"expect"`
+	From   uint64          `json:"from"`
+	Keys   string          `json:"keys"`
+	Limit  int             `json:"limit"`
+}
+
+// Log answers a bundle's `append`, `read`, `last` and `info` on its module's log (ADR 0297). The runtime
+// refuses, with the reason, a log the module was not issued; an append whose `expect` is stale is
+// refused with the code of a lost state update.
+func (b *moduleBus) Log(verb string, params json.RawMessage) (json.RawMessage, error) {
+	var asked logAsked
+	if err := json.Unmarshal(params, &asked); err != nil || asked.Log == "" {
+		return nil, fmt.Errorf("mesh/log.%s names no log: {log, ...}", verb)
+	}
+	conn := b.all.conn
+	var answer any
+	switch verb {
+	case "append":
+		seq, err := conn.LogAppend(b.module, asked.Log, asked.Key, asked.Value, asked.Expect)
+		if err != nil {
+			return nil, err
+		}
+		answer = map[string]any{"sequence": seq}
+	case "read":
+		page, err := conn.LogRead(b.module, asked.Log, asked.From, asked.Keys, asked.Limit)
+		if err != nil {
+			return nil, err
+		}
+		answer = page
+	case "last":
+		entry, err := conn.LogLast(b.module, asked.Log, asked.Key)
+		if err != nil {
+			return nil, err
+		}
+		if entry == nil {
+			return json.RawMessage("null"), nil
+		}
+		answer = entry
+	case "info":
+		info, err := conn.LogInfo(b.module, asked.Log)
+		if err != nil {
+			return nil, err
+		}
+		answer = info
+	default:
+		return nil, fmt.Errorf("the runtime answers no mesh/log.%s", verb)
+	}
+	return json.Marshal(answer)
+}
+
+// Watch hands a bundle its module's state as it is and as it changes (ADR 0201): `{state, key}`, the
+// key a pattern with `*` and `**`, empty for every key.
+func (b *moduleBus) Watch(params json.RawMessage, deliver func(json.RawMessage) error) (func(), error) {
+	var asked stateAsked
+	if err := json.Unmarshal(params, &asked); err != nil || asked.State == "" {
+		return nil, fmt.Errorf("mesh/state.watch names no state: {state, key}")
+	}
+	return b.all.conn.StateWatch(b.module, asked.State, asked.Key, func(change bus.StateChange) error {
+		raw, err := json.Marshal(change)
+		if err != nil {
+			return err
+		}
+		return deliver(raw)
+	})
+}
+
+// seatAsked is what a bundle names for its seat traffic (novox/hq ADR 0259 §3).
+type seatAsked struct {
+	Subject string          `json:"subject"`
+	Body    json.RawMessage `json:"body"`
+	ID      string          `json:"id"`
+	Worker  string          `json:"worker"`
+	Bucket  string          `json:"bucket"`
+	Key     string          `json:"key"`
+}
+
+// Seat answers a bundle's seat traffic, each as the module and only as far as its membership lists:
+// `publish` an accept or an event, `prove` (ask a proof), `record` (read a record kept for it), `take` a
+// worker's work and `answer` a proof subject — the last two bound once per module and subject, each
+// message or proof handed to the module's child that asked last (novox/hq ADR 0259 §3).
+func (b *moduleBus) Seat(verb string, params json.RawMessage, handOn func(string, any) (json.RawMessage, error)) (json.RawMessage, error) {
+	var asked seatAsked
+	if err := json.Unmarshal(params, &asked); err != nil {
+		return nil, fmt.Errorf("mesh/seat.%s: %w", verb, err)
+	}
+	conn := b.all.conn
+	switch verb {
+	case "publish":
+		seq, duplicate, err := conn.SeatPublishSaid(b.module, asked.Subject, asked.Body, asked.ID)
+		if err != nil {
+			return nil, err
+		}
+		return json.Marshal(map[string]any{"sequence": seq, "duplicate": duplicate})
+	case "prove":
+		return conn.SeatProve(b.module, asked.Subject, asked.Body)
+	case "kinds":
+		kinds, err := conn.SeatKinds(b.module)
+		if err != nil {
+			return nil, err
+		}
+		return json.Marshal(kinds)
+	case "record":
+		entry, err := conn.SeatRecord(b.module, asked.Bucket, asked.Key)
+		if err != nil || entry == nil {
+			return json.RawMessage("null"), err
+		}
+		return json.Marshal(entry)
+	case "take":
+		key := "take " + asked.Worker
+		if b.bound(key) {
+			return json.RawMessage(`{}`), nil
+		}
+		stop, err := conn.SeatTake(b.module, asked.Worker, func(w bus.Work) error {
+			_, err := handOn("mesh/work", map[string]any{"work": w})
+			return err
+		})
+		if err != nil {
+			return nil, err
+		}
+		b.bind(key, stop)
+		b.all.logf("[mesh-tools] %s takes its work from %s", b.module, asked.Worker)
+		return json.RawMessage(`{}`), nil
+	case "answer":
+		key := "answer " + asked.Subject
+		if b.bound(key) {
+			return json.RawMessage(`{}`), nil
+		}
+		stop, err := conn.SeatAnswer(b.module, asked.Subject, func(subject string, body json.RawMessage) (json.RawMessage, error) {
+			return handOn("mesh/proof", map[string]any{"subject": subject, "body": body})
+		})
+		if err != nil {
+			return nil, err
+		}
+		b.bind(key, stop)
+		b.all.logf("[mesh-tools] %s answers the proofs on %s", b.module, asked.Subject)
+		return json.RawMessage(`{}`), nil
+	}
+	return nil, fmt.Errorf("the runtime answers no mesh/seat.%s", verb)
+}
+
+// bound and bind keep, per module, what its seat traffic is bound to, so a child that starts again and
+// asks again is handed what is already bound instead of a second reader of it.
+func (b *moduleBus) bound(key string) bool {
+	b.all.mu.Lock()
+	defer b.all.mu.Unlock()
+	_, ok := b.all.seatBound[b.module+" "+key]
+	return ok
+}
+
+func (b *moduleBus) bind(key string, stop func()) {
+	b.all.mu.Lock()
+	defer b.all.mu.Unlock()
+	if b.all.seatBound == nil {
+		b.all.seatBound = map[string]func(){}
+	}
+	b.all.seatBound[b.module+" "+key] = stop
+}
+
+// BundleEnv is what one module's bundle is started with: the runtime's environment without its own words,
+// the module's composed words over it, and the module's and machine's names. **No bus word reaches a
+// bundle** (security review of 2026-10-08): the credential and the bus's address are the runtime's, and a
+// bundle reaches the bus only through the runtime.
+func BundleEnv(base []string, given map[string]string, module, node string) []string {
+	words := map[string]string{}
+	for _, kv := range base {
+		if k, v, ok := strings.Cut(kv, "="); ok && !runtimeOnly[k] {
+			words[k] = v
+		}
+	}
+	for k, v := range given {
+		if !runtimeOnly[k] {
+			words[k] = v
+		}
+	}
+	words["MESH_SERVED_MODULE"] = module
+	words["MESH_MODULE"] = module
+	if node != "" {
+		words["MESH_NODE"] = node
+	}
+	out := make([]string, 0, len(words))
+	for k, v := range words {
+		out = append(out, k+"="+v)
+	}
+	sort.Strings(out)
+	return out
+}

node-tools/internal/runtime/runtime_test.go

@@ -0,0 +1,268 @@
+package runtime
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/launch"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+func connect(t *testing.T, module, node string) *bus.Conn {
+	t.Helper()
+	c, err := bus.Connect(bus.Credential{URL: mt.URL(t), Module: module, Node: node})
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.Logf = func(string, ...any) {}
+	t.Cleanup(c.Close)
+	return c
+}
+
+func call(t *testing.T, asker *bus.Conn, key string, args any) (string, error) {
+	t.Helper()
+	got, err := asker.Ask(key, args, "")
+	return string(got.Result), err
+}
+
+func same(t *testing.T, got, want string) {
+	t.Helper()
+	var a, b any
+	if json.Unmarshal([]byte(got), &a) != nil || json.Unmarshal([]byte(want), &b) != nil {
+		t.Fatalf("not JSON: got %s want %s", got, want)
+	}
+	ga, _ := json.Marshal(a)
+	gb, _ := json.Marshal(b)
+	if string(ga) != string(gb) {
+		t.Errorf("got %s, want %s", got, want)
+	}
+}
+
+// The node's runtime serves five modules' bundles on one credential — two TypeScript, one broken,
+// one Python, one written against the protocol — and follows a re-issued membership (ADR 0175, 0193).
+func TestTheNodesRuntimeServesFiveModulesAndFollowsAReissuedMembership(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("alpha", "anchor", true, nil))
+	mesh.Issue(t, mt.MembershipOf("beta", "anchor", false, map[string][]string{"node-shelf": {"list", "clear"}}))
+	mesh.Issue(t, mt.MembershipOf("gamma", "anchor", false, nil))
+	mesh.Issue(t, mt.MembershipOf("delta", "anchor", false, map[string][]string{"node-lamp": {"on"}}))
+	mesh.Issue(t, mt.MembershipOf("epsilon", "anchor", false, nil))
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	logs := &mt.Logs{}
+	t.Setenv("MESH_OPERATOR_ACCOUNT", "somebody")
+	t.Setenv("MESH_OPERATOR_HOME", "/home/somebody")
+	stop, err := Run(nodeTools, []Served{
+		{"alpha", []string{mt.Fixture("many-alpha.serve.mjs")}},
+		{"beta", []string{mt.Fixture("many-beta.serve.mjs")}},
+		{"gamma", []string{mt.Fixture("many-broken.serve.mjs")}},
+		{"delta", []string{mt.Fixture("many-delta.py")}},
+		{"epsilon", []string{mt.Fixture("many-epsilon.mjs")}},
+	}, nil, logs.Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	if !logs.Has("the operator's account here is somebody (home /home/somebody)") {
+		t.Errorf("the operator was not said:\n%s", logs.All())
+	}
+	if !logs.Has("gamma's bundle", "many-broken.serve.mjs failed to load: gamma's bundle exited (1): Error: gamma's bundle cannot find its client; its tools are not served here") {
+		t.Errorf("the broken bundle was not named with its own words:\n%s", logs.All())
+	}
+	if !logs.Has("serving 8 tool(s) for 5 module(s): alpha.one, alpha.two, beta.three, beta.four, beta.five, delta.greet, delta.die, epsilon.seven; not serving gamma") {
+		t.Errorf("not serving what it should:\n%s", logs.All())
+	}
+
+	for key, want := range map[string]string{
+		"alpha.one": `{"alpha":1}`, "alpha.one@anchor": `{"alpha":1}`, "beta.three@anchor": `{"beta":3}`,
+		"beta.four@anchor": `{"beta":4}`, "beta.five@anchor": `{"beta":5}`,
+		"seat:node-shelf.list@anchor": `{"shelf":["a","b"]}`, "seat:node-shelf.clear@anchor": `{"cleared":true}`,
+		"seat:node-lamp.on@anchor": `{"on":true,"language":"python"}`, "epsilon.seven@anchor": `{"epsilon":7,"via":"stdio"}`,
+	} {
+		got, err := call(t, asker, key, map[string]any{})
+		if err != nil {
+			t.Errorf("%s: %v", key, err)
+			continue
+		}
+		same(t, got, want)
+	}
+	if _, err := call(t, asker, "beta.three", map[string]any{}); err == nil || !strings.Contains(err.Error(), "no responders") {
+		t.Errorf("beta was not issued the plain subject, and answered on it: %v", err)
+	}
+	got, err := call(t, asker, "delta.greet@anchor", map[string]any{"who": "mesh"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"greeting":"hello mesh","language":"python"}`)
+
+	// A launched tool that emits does so as its module, through the runtime.
+	landed := mesh.NextEvent(t, "mesh.mod.*.event.>")
+	got, err = call(t, asker, "alpha.two", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"alpha":2}`)
+	select {
+	case subject := <-landed:
+		if subject != "mesh.mod.alpha.event.happened" {
+			t.Errorf("the event landed on %s", subject)
+		}
+	case <-time.After(5 * time.Second):
+		t.Error("the event never landed")
+	}
+
+	// A bundle that dies mid-call is said, and started again on its next call.
+	if _, err := call(t, asker, "delta.die@anchor", map[string]any{}); err == nil {
+		t.Error("a bundle that died answered")
+	}
+	got, err = call(t, asker, "delta.greet@anchor", map[string]any{"who": "again"})
+	if err != nil {
+		t.Fatalf("not started again: %v", err)
+	}
+	same(t, got, `{"greeting":"hello again","language":"python"}`)
+
+	// `tools` answers for each, and why gamma serves nothing.
+	gamma, err := call(t, asker, "gamma.tools@anchor", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, gamma, `{"module":"gamma","tools":[],"failed":"gamma's bundle exited (1): Error: gamma's bundle cannot find its client"}`)
+	beta, _ := call(t, asker, "beta.tools@anchor", map[string]any{})
+	var answer ToolsAnswer
+	_ = json.Unmarshal([]byte(beta), &answer)
+	if len(answer.Tools) != 3 || answer.Tools[0].Name != "three" || strings.Join(answer.Tools[0].Subjects, ",") != "mesh.mod.beta.tool.three.anchor" {
+		t.Errorf("beta's tools answer: %s", beta)
+	}
+
+	// Re-issued mid-run, now answering for the module anywhere: served without a restart.
+	mesh.Issue(t, mt.MembershipOf("beta", "anchor", true, map[string][]string{"node-shelf": {"list", "clear"}}))
+	mt.Until(t, func() error { _, err := call(t, asker, "beta.three", map[string]any{}); return err })
+	got, err = call(t, asker, "seat:node-shelf.list@anchor", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"shelf":["a","b"]}`)
+}
+
+// Each bundle is given its own environment and none of another's (ADR 0192), and the composed
+// environments are not left in the runtime's.
+func TestEachBundleIsGivenItsOwnEnvironment(t *testing.T) {
+	mesh := mt.New(t)
+	for _, m := range []string{"gamma", "delta", "zeta"} {
+		mesh.Issue(t, mt.MembershipOf(m, "anchor", false, nil))
+	}
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	t.Setenv("MESH_OPERATOR_ACCOUNT", "somebody")
+	t.Setenv(ToolEnv, `{"gamma":{"GAMMA_CONFIG_FILE":"/var/lib/mesh/gamma/config.json"},"delta":{"DELTA_TOKEN_FILE":"/var/lib/mesh/delta/token"},"zeta":{"ZETA_URL":"http://127.0.0.1:3000"}}`)
+	envs, err := TakeToolEnvs()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, left := os.LookupEnv(ToolEnv); left {
+		t.Error("the composed environments were left in the runtime's")
+	}
+	logs := &mt.Logs{}
+	stop, err := Run(nodeTools, []Served{
+		{"gamma", []string{mt.Fixture("env-gamma.serve.mjs")}},
+		{"delta", []string{mt.Fixture("env-delta.serve.mjs")}},
+		{"zeta", []string{mt.Fixture("env-zeta.mjs")}},
+	}, envs, logs.Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	for key, want := range map[string]string{
+		"gamma.given@anchor": `{"mine":"/var/lib/mesh/gamma/config.json","theirs":null,"runtime":"somebody","composed":null}`,
+		"delta.given@anchor": `{"mine":"/var/lib/mesh/delta/token","theirs":null}`,
+		"zeta.given@anchor":  `{"mine":"http://127.0.0.1:3000","theirs":null,"composed":null}`,
+	} {
+		got, err := call(t, asker, key, map[string]any{})
+		if err != nil {
+			t.Fatalf("%s: %v\n%s", key, err, logs.All())
+		}
+		same(t, got, want)
+	}
+}
+
+// An entrypoint that is not executable is refused by name, and the others serve (ADR 0193).
+func TestAnEntrypointThatIsNotExecutableIsRefused(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("alpha", "anchor", false, nil))
+	mesh.Issue(t, mt.MembershipOf("plain", "anchor", false, nil))
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	logs := &mt.Logs{}
+	stop, err := Run(nodeTools, []Served{
+		{"alpha", []string{mt.Fixture("many-alpha.serve.mjs")}},
+		{"plain", []string{mt.Fixture("many-alpha.mjs")}},
+	}, nil, logs.Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	if !logs.Has("plain's bundle", "many-alpha.mjs failed to load:", "is not executable; a bundle the runtime serves is started, never imported") {
+		t.Errorf("the non-executable entrypoint was not refused by name:\n%s", logs.All())
+	}
+	got, err := call(t, asker, "alpha.one@anchor", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"alpha":1}`)
+}
+
+// A launched bundle is told the module it serves, so its seat's verbs stay the seat's (ADR 0193).
+func TestALaunchedBundleRegisteringItsSeatFirstServesTheSeat(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("theta", "anchor", false, map[string][]string{"node-shelf": {"list"}}))
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	stop, err := Run(nodeTools, []Served{{"theta", []string{mt.Fixture("served-seat-first.mjs")}}},
+		map[string]map[string]string{"theta": {"THETA_WORD": "given"}}, (&mt.Logs{}).Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+	got, err := call(t, asker, "theta.own@anchor", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"theta":"given"}`)
+	got, err = call(t, asker, "seat:node-shelf.list@anchor", map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `{"shelf":["x"]}`)
+}
+
+func TestToolModulesNamesOtherModulesOnly(t *testing.T) {
+	got, err := ServedModulesFrom(" alpha=/a/tools/index.serve.mjs, beta=/b/one, beta=/b/two ", "node-tools")
+	if err != nil || len(got) != 2 || got[1].Module != "beta" || len(got[1].Entrypoints) != 2 {
+		t.Fatalf("%v %v", got, err)
+	}
+	for _, bad := range []string{"/mine/index.js", "node-tools=/own.js", "=/x"} {
+		if _, err := ServedModulesFrom(bad, "node-tools"); err == nil {
+			t.Errorf("%q was accepted", bad)
+		}
+	}
+}
+
+// A line about an event a bundle did not take says who failed: the handler in its own words, or the
+// runtime not reaching it (hq issue 276).
+func TestAnUntakenEventSaysWhoFailed(t *testing.T) {
+	handler := whyNotTaken(&launch.Refused{Method: "mesh/event", Message: "Unexpected end of JSON input"})
+	if !strings.Contains(handler, `its handler answered an error, in its own words: "Unexpected end of JSON input"`) {
+		t.Errorf("a handler's error is not said as the handler's: %s", handler)
+	}
+	if got := whyNotTaken(errors.New("plex's bundle did not answer mesh/event in 120s")); got != "plex's bundle did not answer mesh/event in 120s" {
+		t.Errorf("the runtime's own failure is not said as it is: %s", got)
+	}
+	if got := eventRef(bus.Envelope{Headers: map[string]string{"x-event-id": "e1"}}); got != " (event e1)" {
+		t.Errorf("the event is not named by its id: %q", got)
+	}
+}

node-tools/internal/runtime/seat_traffic_test.go

@@ -0,0 +1,149 @@
+package runtime
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// A bundle's seat traffic through moduleBus.Seat (novox/hq ADR 0259 §3), against a real bus: publish under
+// its own name with the id prefixed and a duplicate said; the record read without naming the bucket; a
+// worker and a proof subject bound once however often a restarted child asks; and nothing beyond what the
+// membership lists.
+func TestABundlesSeatTrafficGoesThroughItsModulesBus(t *testing.T) {
+	mesh := mt.New(t)
+	nc, err := nats.Connect(mt.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(nc.Close)
+	js, _ := nc.JetStream()
+	if _, err := js.AddStream(&nats.StreamConfig{Name: "SEAT_OPERATOR_CHANNEL", Retention: nats.WorkQueuePolicy,
+		Subjects: []string{"mesh.seat.operator-channel.accept.>"}}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := js.AddConsumer("SEAT_OPERATOR_CHANNEL", &nats.ConsumerConfig{Durable: "SEAT_OPERATOR_CHANNEL_worker",
+		AckPolicy: nats.AckExplicitPolicy, FilterSubject: "mesh.seat.operator-channel.accept.>"}); err != nil {
+		t.Fatal(err)
+	}
+	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{Bucket: "messenger_asks"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, _ = kv.Put("mesh-delivery.d-1", []byte(`{"state":"open"}`))
+	asker := mt.MembershipOf("mesh-delivery", "anchor", false, nil)
+	asker.SeatTraffic = &bus.SeatTraffic{Publish: []string{"mesh.seat.operator-channel.accept.ask.mesh-delivery"},
+		Records: []string{"$JS.API.DIRECT.GET.KV_messenger_asks.$KV.messenger_asks.mesh-delivery.>"}}
+	router := mt.MembershipOf("messenger", "anchor", false, nil)
+	router.SeatTraffic = &bus.SeatTraffic{Answers: []string{"mesh.seat.intake.proof.code.*"},
+		Workers: []bus.SeatWorker{{Stream: "SEAT_OPERATOR_CHANNEL", Consumer: "SEAT_OPERATOR_CHANNEL_worker",
+			Filter: "mesh.seat.operator-channel.accept.>"}}}
+	mesh.Issue(t, asker)
+	mesh.Issue(t, router)
+	conn := connect(t, "node-tools", "anchor")
+	conn.Follow("mesh-delivery")
+	conn.Follow("messenger")
+	mt.Until(t, func() error {
+		if conn.Membership("mesh-delivery") == nil || conn.Membership("messenger") == nil {
+			return errors.New("not issued yet")
+		}
+		return nil
+	})
+	all := &consumers{conn: conn, logf: t.Logf, of: map[string]*moduleEvents{}}
+	asking := all.forModule("mesh-delivery").(*moduleBus)
+	routing := all.forModule("messenger").(*moduleBus)
+
+	publish := json.RawMessage(`{"subject":"mesh.seat.operator-channel.accept.ask.mesh-delivery","body":{"id":"d-1"},"id":"d-1"}`)
+	first, err := asking.Seat("publish", publish, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	again, _ := asking.Seat("publish", publish, nil)
+	if !strings.Contains(string(first), `"duplicate":false`) || !strings.Contains(string(again), `"duplicate":true`) {
+		t.Errorf("the same id twice: %s, then %s", first, again)
+	}
+	if _, err := asking.Seat("publish", json.RawMessage(`{"subject":"mesh.seat.operator-channel.accept.ask.mesh-controller","body":{}}`), nil); err == nil {
+		t.Error("a module submitted under another's name")
+	}
+	got, err := asking.Seat("record", json.RawMessage(`{"key":"d-1"}`), nil)
+	if err != nil || !strings.Contains(string(got), `"state":"open"`) {
+		t.Errorf("the record read without its bucket: %s %v", got, err)
+	}
+
+	var mu sync.Mutex
+	var taken []string
+	handOn := func(method string, params any) (json.RawMessage, error) {
+		mu.Lock()
+		defer mu.Unlock()
+		raw, _ := json.Marshal(params)
+		taken = append(taken, method+" "+string(raw))
+		return json.RawMessage(`{}`), nil
+	}
+	for i := 0; i < 2; i++ { // a child that started again asks again
+		if _, err := routing.Seat("take", json.RawMessage(`{"worker":"SEAT_OPERATOR_CHANNEL_worker"}`), handOn); err != nil {
+			t.Fatal(err)
+		}
+	}
+	deadline := time.Now().Add(10 * time.Second)
+	for {
+		mu.Lock()
+		n := len(taken)
+		mu.Unlock()
+		if n >= 1 || time.Now().After(deadline) {
+			break
+		}
+		time.Sleep(50 * time.Millisecond)
+	}
+	time.Sleep(300 * time.Millisecond)
+	mu.Lock()
+	if len(taken) != 1 || !strings.Contains(taken[0], "mesh/work") || !strings.Contains(taken[0], `"x-event-id":"mesh-delivery.d-1"`) {
+		t.Errorf("taken %v", taken)
+	}
+	mu.Unlock()
+	if _, err := asking.Seat("take", json.RawMessage(`{"worker":"SEAT_OPERATOR_CHANNEL_worker"}`), handOn); err == nil {
+		t.Error("an asker took the router's work")
+	}
+	if _, err := asking.Seat("answer", json.RawMessage(`{"subject":"mesh.seat.intake.proof.code.*"}`), handOn); err == nil {
+		t.Error("an asker answered proofs")
+	}
+	if _, err := asking.Seat("anything", json.RawMessage(`{}`), nil); err == nil {
+		t.Error("an unknown verb was answered")
+	}
+}
+
+// A lost compare-and-set is answered with its code, so the SDK knows it without reading words.
+func TestALostCompareAndSetCarriesItsCode(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Bucket(t, "messenger_asks")
+	m := mt.MembershipOf("messenger", "anchor", false, nil)
+	m.State = []bus.StateIssued{{Name: "asks", Bucket: "messenger_asks", Writes: true}}
+	mesh.Issue(t, m)
+	conn := connect(t, "node-tools", "anchor")
+	conn.Follow("messenger")
+	mt.Until(t, func() error {
+		if conn.Membership("messenger") == nil {
+			return errors.New("not issued yet")
+		}
+		return nil
+	})
+	b := (&consumers{conn: conn, logf: t.Logf, of: map[string]*moduleEvents{}}).forModule("messenger")
+	if _, err := b.State("create", json.RawMessage(`{"state":"asks","key":"a","value":{}}`)); err != nil {
+		t.Fatal(err)
+	}
+	_, err := b.State("create", json.RawMessage(`{"state":"asks","key":"a","value":{}}`))
+	var coded interface{ ErrorCode() int }
+	if !errors.As(err, &coded) || coded.ErrorCode() != -32010 || !errors.Is(err, bus.ErrStateChanged) {
+		t.Errorf("a second create: %v", err)
+	}
+	if _, err := b.State("update", json.RawMessage(`{"state":"asks","key":"a","value":{},"revision":0}`)); err == nil {
+		t.Error("an update of revision zero was taken")
+	}
+}

node-tools/internal/runtime/state_counter_test.go

@@ -0,0 +1,203 @@
+package runtime
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"sync"
+	"testing"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/launch"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// counterBus is a module, issues, that keeps a state numbers in a bucket of a real bus, reached as a bundle
+// reaches it: mesh/state.<verb> with its JSON, through the module's bus.
+func counterBus(t *testing.T) launch.Bus {
+	t.Helper()
+	mesh := mt.New(t)
+	mesh.Bucket(t, "issues_numbers")
+	m := mt.MembershipOf("issues", "anchor", false, nil)
+	m.State = []bus.StateIssued{{Name: "numbers", Bucket: "issues_numbers", Writes: true}}
+	mesh.Issue(t, m)
+	conn := connect(t, "node-tools", "anchor")
+	conn.Follow("issues")
+	mt.Until(t, func() error {
+		if conn.Membership("issues") == nil {
+			return errors.New("not issued yet")
+		}
+		return nil
+	})
+	return (&consumers{conn: conn, logf: t.Logf, of: map[string]*moduleEvents{}}).forModule("issues")
+}
+
+func ask(b launch.Bus, verb string, params map[string]any) (json.RawMessage, error) {
+	raw, _ := json.Marshal(params)
+	return b.State(verb, raw)
+}
+
+// increment is what a bundle's counter does over the wire: get, then create (no value) or update at the
+// revision read; a lost write — told by its code alone — is read again and tried again.
+func increment(b launch.Bus, key string, attempts int) (n uint64, lost int, err error) {
+	for i := 0; i < attempts; i++ {
+		raw, err := ask(b, "get", map[string]any{"state": "numbers", "key": key})
+		if err != nil {
+			return 0, lost, err
+		}
+		var e *bus.StateEntry
+		if err := json.Unmarshal(raw, &e); err != nil {
+			return 0, lost, err
+		}
+		if e == nil {
+			n = 1
+			_, err = ask(b, "create", map[string]any{"state": "numbers", "key": key, "value": n})
+		} else {
+			if err := json.Unmarshal(e.Value, &n); err != nil {
+				return 0, lost, err
+			}
+			n++
+			_, err = ask(b, "update", map[string]any{"state": "numbers", "key": key, "value": n, "revision": e.Revision})
+		}
+		var coded interface{ ErrorCode() int }
+		switch {
+		case err == nil:
+			return n, lost, nil
+		case errors.As(err, &coded) && coded.ErrorCode() == launch.CodeChanged:
+			lost++
+		default:
+			return 0, lost, err
+		}
+	}
+	return 0, lost, fmt.Errorf("%s lost %d times", key, attempts)
+}
+
+// Two writers incrementing one counter a thousand times each, against a real bus, end at two thousand:
+// every number handed out once and none lost, because the runtime writes only at the revision read
+// (novox/hq research 042: an issue's number is handed out once).
+func TestTwoWritersIncrementingOneCounterOnTheBusLoseNoUpdate(t *testing.T) {
+	b := counterBus(t)
+	const each = 1000
+	var wg sync.WaitGroup
+	numbers := make([][]uint64, 2)
+	errs := make([]error, 2)
+	lost := make([]int, 2)
+	for w := range numbers {
+		wg.Add(1)
+		go func(w int) {
+			defer wg.Done()
+			for i := 0; i < each; i++ {
+				n, l, err := increment(b, "issue", 1000)
+				lost[w] += l
+				if err != nil {
+					errs[w] = err
+					return
+				}
+				numbers[w] = append(numbers[w], n)
+			}
+		}(w)
+	}
+	wg.Wait()
+	if err := errors.Join(errs...); err != nil {
+		t.Fatal(err)
+	}
+	seen := map[uint64]bool{}
+	for w, ns := range numbers {
+		for i, n := range ns {
+			if seen[n] {
+				t.Errorf("the number %d was handed out twice", n)
+			}
+			seen[n] = true
+			if i > 0 && n <= ns[i-1] {
+				t.Errorf("writer %d was handed %d after %d", w, n, ns[i-1])
+			}
+		}
+	}
+	raw, err := ask(b, "get", map[string]any{"state": "numbers", "key": "issue"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var e bus.StateEntry
+	_ = json.Unmarshal(raw, &e)
+	if string(e.Value) != "2000" || len(seen) != 2*each {
+		t.Fatalf("the counter ended at %s with %d numbers handed out, not 2000: an increment was lost", e.Value, len(seen))
+	}
+	if lost[0]+lost[1] == 0 {
+		t.Fatal("the two writers never collided: the test proved nothing about contention")
+	}
+	t.Logf("2000 increments, %d writes lost to the other writer and tried again", lost[0]+lost[1])
+}
+
+// A write at a revision that is no longer the key's is refused with the lost-write code and writes
+// nothing; create is refused for a key with a value and taken for one deleted; an update names the
+// revision it read, never zero.
+func TestAStaleWriteIsRefusedAndWritesNothing(t *testing.T) {
+	b := counterBus(t)
+	state := func(verb string, extra map[string]any) (uint64, error) {
+		p := map[string]any{"state": "numbers", "key": "issue"}
+		for k, v := range extra {
+			p[k] = v
+		}
+		raw, err := ask(b, verb, p)
+		if err != nil {
+			return 0, err
+		}
+		var r struct {
+			Revision uint64 `json:"revision"`
+		}
+		_ = json.Unmarshal(raw, &r)
+		return r.Revision, nil
+	}
+	isLost := func(err error) bool {
+		var coded interface{ ErrorCode() int }
+		return errors.As(err, &coded) && coded.ErrorCode() == launch.CodeChanged && errors.Is(err, bus.ErrStateChanged)
+	}
+	value := func() string {
+		raw, err := ask(b, "get", map[string]any{"state": "numbers", "key": "issue"})
+		if err != nil {
+			t.Fatal(err)
+		}
+		var e *bus.StateEntry
+		_ = json.Unmarshal(raw, &e)
+		if e == nil {
+			return "none"
+		}
+		return string(e.Value)
+	}
+
+	if _, err := state("update", map[string]any{"value": 1, "revision": 0}); err == nil || isLost(err) {
+		t.Fatalf("an update at revision zero: %v", err)
+	}
+	if value() != "none" {
+		t.Fatal("an update at revision zero wrote")
+	}
+	first, err := state("create", map[string]any{"value": 1})
+	if err != nil || first == 0 {
+		t.Fatalf("create of a key with no value: %d %v", first, err)
+	}
+	if _, err := state("create", map[string]any{"value": 9}); !isLost(err) {
+		t.Fatalf("a second create: %v", err)
+	}
+	second, err := state("update", map[string]any{"value": 2, "revision": first})
+	if err != nil || second <= first {
+		t.Fatalf("an update at the revision read: %d %v", second, err)
+	}
+	if _, err := state("update", map[string]any{"value": 9, "revision": first}); !isLost(err) {
+		t.Fatalf("an update at a stale revision: %v", err)
+	}
+	if _, err := state("update", map[string]any{"value": 9, "revision": second + 100}); !isLost(err) {
+		t.Fatalf("an update at a revision not yet written: %v", err)
+	}
+	if v := value(); v != "2" {
+		t.Fatalf("refused writes changed the value to %s", v)
+	}
+	if _, err := ask(b, "delete", map[string]any{"state": "numbers", "key": "issue"}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := state("create", map[string]any{"value": 1}); err != nil {
+		t.Fatalf("create of a deleted key: %v", err)
+	}
+	if v := value(); v != "1" {
+		t.Fatalf("after delete and create: %s", v)
+	}
+}

node-tools/internal/runtime/state_history_test.go

@@ -0,0 +1,152 @@
+package runtime
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	"github.com/novox/mesh-tools/node-tools/internal/launch"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// historyBuses are three modules on one runtime, each reached as a bundle reaches it (novox/hq ADR
+// 0307): issues keeps a state `issues` in a bucket keeping 8 values a key, triage reads it as
+// `issues.issues`, and other was issued no state.
+func historyBuses(t *testing.T) (owner, reader, other launch.Bus) {
+	t.Helper()
+	mesh := mt.New(t)
+	mesh.BucketKeeping(t, "issues_issues", 8)
+	m := mt.MembershipOf("issues", "anchor", false, nil)
+	m.State = []bus.StateIssued{{Name: "issues", Bucket: "issues_issues", Writes: true}}
+	mesh.Issue(t, m)
+	r := mt.MembershipOf("triage", "anchor", false, nil)
+	r.State = []bus.StateIssued{{Name: "issues.issues", Bucket: "issues_issues"}}
+	mesh.Issue(t, r)
+	mesh.Issue(t, mt.MembershipOf("other", "anchor", false, nil))
+	conn := connect(t, "node-tools", "anchor")
+	for _, module := range []string{"issues", "triage", "other"} {
+		conn.Follow(module)
+	}
+	mt.Until(t, func() error {
+		for _, module := range []string{"issues", "triage", "other"} {
+			if conn.Membership(module) == nil {
+				return errors.New(module + " not issued yet")
+			}
+		}
+		return nil
+	})
+	all := &consumers{conn: conn, logf: t.Logf, of: map[string]*moduleEvents{}}
+	return all.forModule("issues"), all.forModule("triage"), all.forModule("other")
+}
+
+// kept is one value of a history answer, by the field names on the wire.
+type kept struct {
+	Key      string          `json:"key"`
+	Value    json.RawMessage `json:"value"`
+	Revision uint64          `json:"revision"`
+	Op       string          `json:"op"`
+	At       string          `json:"at"`
+}
+
+func historyOf(t *testing.T, b launch.Bus, state, key string) []kept {
+	t.Helper()
+	raw, err := ask(b, "history", map[string]any{"state": state, "key": key})
+	if err != nil {
+		t.Fatalf("history of %s %s: %v", state, key, err)
+	}
+	var h []kept
+	if err := json.Unmarshal(raw, &h); err != nil || h == nil {
+		t.Fatalf("history answered %s, not an array", raw)
+	}
+	return h
+}
+
+// A key's history is every value the bucket keeps, oldest first, each with its revision, op and time
+// in RFC 3339 — a delete with no value; an unknown key's is []. The owner and a reader are served it,
+// and reading it writes nothing.
+func TestAKeysHistoryIsEveryValueKeptOldestFirst(t *testing.T) {
+	owner, reader, _ := historyBuses(t)
+	before := time.Now().Add(-time.Second)
+	var revisions []uint64
+	for _, v := range []string{`{"state":"open"}`, `{"state":"fixing"}`, `{"state":"resolved"}`} {
+		raw, err := ask(owner, "put", map[string]any{"state": "issues", "key": "502", "value": json.RawMessage(v)})
+		if err != nil {
+			t.Fatal(err)
+		}
+		var r struct {
+			Revision uint64 `json:"revision"`
+		}
+		_ = json.Unmarshal(raw, &r)
+		revisions = append(revisions, r.Revision)
+	}
+	if _, err := ask(owner, "put", map[string]any{"state": "issues", "key": "503", "value": 1}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := ask(owner, "delete", map[string]any{"state": "issues", "key": "502"}); err != nil {
+		t.Fatal(err)
+	}
+
+	for who, b := range map[string]launch.Bus{"the owner": owner, "a reader": reader} {
+		name := "issues"
+		if b == reader {
+			name = "issues.issues"
+		}
+		h := historyOf(t, b, name, "502")
+		if len(h) != 4 {
+			t.Fatalf("%s read %d values of 502, not 4: %+v", who, len(h), h)
+		}
+		for i, v := range []string{`{"state":"open"}`, `{"state":"fixing"}`, `{"state":"resolved"}`} {
+			if h[i].Op != "put" || string(h[i].Value) != v || h[i].Revision != revisions[i] || h[i].Key != "502" {
+				t.Errorf("%s: value %d is %+v", who, i, h[i])
+			}
+		}
+		if h[3].Op != "delete" || len(h[3].Value) != 0 && string(h[3].Value) != "null" || h[3].Revision <= revisions[2] {
+			t.Errorf("%s: the delete reads %+v", who, h[3])
+		}
+		for i, k := range h {
+			at, err := time.Parse(time.RFC3339, k.At)
+			if err != nil || at.Before(before) || at.After(time.Now().Add(time.Second)) {
+				t.Errorf("%s: value %d's time %q is not RFC 3339 and now: %v", who, i, k.At, err)
+			}
+			if i > 0 && k.Revision <= h[i-1].Revision {
+				t.Errorf("%s: not oldest first: %+v", who, h)
+			}
+		}
+		if h := historyOf(t, b, name, "999"); len(h) != 0 {
+			t.Errorf("%s: an unknown key's history is %+v, not []", who, h)
+		}
+	}
+	// The history is read, never written: the key is still deleted and keeps the same four values.
+	if raw, err := ask(owner, "get", map[string]any{"state": "issues", "key": "502"}); err != nil || string(raw) != "null" {
+		t.Fatalf("after history, 502 reads %s %v", raw, err)
+	}
+	if h := historyOf(t, owner, "issues", "502"); len(h) != 4 {
+		t.Fatalf("reading the history changed it: %+v", h)
+	}
+	// A key the bucket holds nothing for answers [] on the wire, not null.
+	if raw, _ := ask(owner, "history", map[string]any{"state": "issues", "key": "999"}); string(raw) != "[]" {
+		t.Fatalf("an unknown key's history is %s on the wire", raw)
+	}
+}
+
+// A module the bucket was not issued to is refused its history with the reason, as it is a get.
+func TestAKeysHistoryIsRefusedToAModuleNotIssuedTheState(t *testing.T) {
+	owner, _, other := historyBuses(t)
+	if _, err := ask(owner, "put", map[string]any{"state": "issues", "key": "1", "value": 1}); err != nil {
+		t.Fatal(err)
+	}
+	for _, name := range []string{"issues", "issues.issues"} {
+		_, err := ask(other, "history", map[string]any{"state": name, "key": "1"})
+		if err == nil || !strings.Contains(err.Error(), "keeps and reads no state called") ||
+			!strings.Contains(err.Error(), "issued: none") {
+			t.Errorf("history of %s to a module not issued it: %v", name, err)
+		}
+	}
+	if _, err := ask(owner, "history", map[string]any{"state": "issues", "key": "a b"}); err == nil ||
+		!strings.Contains(err.Error(), "not a key") {
+		t.Errorf("history of a key the bus cannot hold: %v", err)
+	}
+}

node-tools/internal/runtime/state_test.go

@@ -0,0 +1,178 @@
+package runtime
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// novox/hq ADR 0201: a module keeps its current state in buckets it declares, and its code reaches
+// them through the runtime. The owner's instances write and read; a reader only reads; a watch hands
+// the current values — none that is deleted — and then every change; the runtime refuses, with the
+// reason, what the module was not issued, a write to state it only reads, and a value naming a
+// credential.
+func TestABundleKeepsAndWatchesItsStateThroughTheRuntime(t *testing.T) {
+	mesh := mt.New(t)
+	kv := mesh.Bucket(t, "keeper_servers")
+	// What was there before anything started: one value, and one key since deleted.
+	if _, err := kv.Put("all.one", []byte(`{"url":"http://one"}`)); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := kv.Put("all.gone", []byte(`{}`)); err != nil {
+		t.Fatal(err)
+	}
+	if err := kv.Delete("all.gone"); err != nil {
+		t.Fatal(err)
+	}
+
+	keeper := mt.MembershipOf("keeper", "anchor", false, nil)
+	keeper.State = []bus.StateIssued{{Name: "servers", Bucket: "keeper_servers", Writes: true}}
+	peeker := mt.MembershipOf("peeker", "anchor", false, nil)
+	peeker.State = []bus.StateIssued{{Name: "keeper.servers", Bucket: "keeper_servers"}}
+	mesh.Issue(t, keeper)
+	mesh.Issue(t, peeker)
+
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	dir := t.TempDir()
+	keeperLog, peekerLog := filepath.Join(dir, "keeper.log"), filepath.Join(dir, "peeker.log")
+	said := &lines{}
+	stop, err := Run(nodeTools, []Served{
+		{Module: "keeper", Entrypoints: []string{mt.Fixture("state-keeper.mjs")}},
+		{Module: "peeker", Entrypoints: []string{mt.Fixture("state-keeper.mjs")}},
+	}, map[string]map[string]string{
+		"keeper": {"STATE_NAME": "servers", "STATE_LOG": keeperLog},
+		"peeker": {"STATE_NAME": "keeper.servers", "STATE_LOG": peekerLog},
+	}, said.logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+
+	// Both read the whole current state at start: the value, not the deleted key, then the end of it.
+	for _, log := range []string{keeperLog, peekerLog} {
+		waitFor(t, log, "current")
+		lines := read(t, log)
+		if lines[0] != `was put all.one {"url":"http://one"}` || lines[1] != "current" || strings.Contains(strings.Join(lines, "\n"), "all.gone") {
+			t.Fatalf("the current state was not handed over as it is:\n%s\nruntime:\n%s", strings.Join(lines, "\n"), said.all())
+		}
+	}
+
+	// The owner writes; every watch sees the change.
+	got, err := call(t, asker, "keeper.put@anchor", map[string]any{"state": "servers", "key": "anchor.two", "value": map[string]any{"url": "http://two"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(got, `"revision"`) {
+		t.Fatalf("a put answered %s", got)
+	}
+	waitFor(t, keeperLog, `now put anchor.two {"url":"http://two"}`)
+	waitFor(t, peekerLog, `now put anchor.two {"url":"http://two"}`)
+
+	// Get and keys, by the owner and by the reader.
+	got, err = call(t, asker, "peeker.get@anchor", map[string]any{"state": "keeper.servers", "key": "anchor.two"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(got, `"value":{"url":"http://two"}`) {
+		t.Fatalf("the reader's get answered %s", got)
+	}
+	got, err = call(t, asker, "peeker.get@anchor", map[string]any{"state": "keeper.servers", "key": "nothing.here"})
+	if err != nil || got != "null" {
+		t.Fatalf("a key with no value answered %s, %v", got, err)
+	}
+	got, err = call(t, asker, "keeper.keys@anchor", map[string]any{"state": "servers"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	same(t, got, `["all.one","anchor.two"]`)
+
+	// Refused, with the reason, before anything is sent.
+	for _, c := range []struct {
+		key, why string
+		args     map[string]any
+	}{
+		{"peeker.put@anchor", "peeker reads keeper.servers and does not keep it",
+			map[string]any{"state": "keeper.servers", "key": "x", "value": 1}},
+		{"keeper.get@anchor", `keeper keeps and reads no state called "other"`,
+			map[string]any{"state": "other", "key": "x"}},
+		{"keeper.put@anchor", `carries a field "accessToken", which names a credential`,
+			map[string]any{"state": "servers", "key": "x", "value": map[string]any{"headers": map[string]any{"accessToken": "s"}}}},
+		{"keeper.put@anchor", "is not a key the bus can hold",
+			map[string]any{"state": "servers", "key": "a..b", "value": 1}},
+	} {
+		if _, err := call(t, asker, c.key, c.args); err == nil || !strings.Contains(err.Error(), c.why) {
+			t.Errorf("%s %v: want refused for %q, got %v", c.key, c.args, c.why, err)
+		}
+	}
+
+	// A delete reaches every watch.
+	if _, err := call(t, asker, "keeper.del@anchor", map[string]any{"state": "servers", "key": "all.one"}); err != nil {
+		t.Fatal(err)
+	}
+	waitFor(t, peekerLog, "now delete all.one")
+	waitFor(t, keeperLog, "now delete all.one")
+}
+
+func read(t *testing.T, path string) []string {
+	t.Helper()
+	b, _ := os.ReadFile(path)
+	return strings.Split(strings.TrimSpace(string(b)), "\n")
+}
+
+func waitFor(t *testing.T, path, line string) {
+	t.Helper()
+	mt.Until(t, func() error {
+		for _, l := range read(t, path) {
+			if l == line {
+				return nil
+			}
+		}
+		return errorf("%s has no %q yet: %s", filepath.Base(path), line, strings.Join(read(t, path), " | "))
+	})
+}
+
+// The TypeScript SDK against the runtime (ADR 0201): two watches of one state, each handed only its
+// own changes, the current values handled before the module's import goes on.
+func TestTheSDKsStateReachesTheRuntime(t *testing.T) {
+	mesh := mt.New(t)
+	kv := mesh.Bucket(t, "sdkkeeper_servers")
+	if _, err := kv.Put("all.one", []byte(`{"url":"http://one"}`)); err != nil {
+		t.Fatal(err)
+	}
+	m := mt.MembershipOf("sdkkeeper", "anchor", false, nil)
+	m.State = []bus.StateIssued{{Name: "servers", Bucket: "sdkkeeper_servers", Writes: true}}
+	mesh.Issue(t, m)
+	nodeTools := connect(t, "node-tools", "anchor")
+	asker := connect(t, "console", "workstation")
+	log := filepath.Join(t.TempDir(), "sdk.log")
+	said := &lines{}
+	stop, err := Run(nodeTools, []Served{{Module: "sdkkeeper", Entrypoints: []string{mt.Fixture("state-sdk.serve.mjs")}}},
+		map[string]map[string]string{"sdkkeeper": {"STATE_LOG": log}}, said.logf)
+	if err != nil {
+		t.Fatalf("%v\n%s", err, said.all())
+	}
+	t.Cleanup(stop)
+	waitFor(t, log, "current")
+	if got := strings.Join(read(t, log), " | "); got != "was put all.one | current" {
+		t.Fatalf("the import went on with %q", got)
+	}
+	if _, err := call(t, asker, "sdkkeeper.register@anchor", map[string]any{"key": "anchor.two", "url": "http://two"}); err != nil {
+		t.Fatal(err)
+	}
+	waitFor(t, log, "now put anchor.two")
+	waitFor(t, log, "narrow put anchor.two")
+	if _, err := call(t, asker, "sdkkeeper.register@anchor", map[string]any{"key": "all.three", "url": "http://three"}); err != nil {
+		t.Fatal(err)
+	}
+	waitFor(t, log, "now put all.three")
+	for _, l := range read(t, log) {
+		if l == "narrow put all.three" {
+			t.Fatalf("a narrowed watch was handed a key outside it: %s", strings.Join(read(t, log), " | "))
+		}
+	}
+}

node-tools/internal/wire/wire.go

@@ -0,0 +1,18 @@
+// Package wire is JSON as the TypeScript runtime writes it: no HTML escaping of <, > and &.
+package wire
+
+import (
+	"bytes"
+	"encoding/json"
+)
+
+// Marshal encodes v the way JSON.stringify does, without a trailing newline.
+func Marshal(v any) ([]byte, error) {
+	var b bytes.Buffer
+	enc := json.NewEncoder(&b)
+	enc.SetEscapeHTML(false)
+	if err := enc.Encode(v); err != nil {
+		return nil, err
+	}
+	return bytes.TrimRight(b.Bytes(), "\n"), nil
+}

node-tools/module.json

@@ -0,0 +1,56 @@
+{
+  "module": "node-tools",
+  "version": "1",
+  "slug": "node-tools",
+  "invokes": [
+    "*"
+  ],
+  "provides": [
+    {
+      "name": "mcp-endpoint",
+      "scope": "node"
+    }
+  ],
+  "serves": {
+    "mcp-endpoint": {
+      "port": 4270
+    }
+  },
+  "own-secrets": {
+    "broker": "${dir:mesh-state}/broker"
+  },
+  "listens": [
+    {
+      "name": "mcp",
+      "port": 4270,
+      "protocol": "tcp",
+      "from": "machine",
+      "why": "the mesh's tools for whoever is on this machine, over MCP on loopback; the machine's login is the authority (novox/hq ADR 0152, 0175)"
+    }
+  ],
+  "resources": [
+    {
+      "id": "mesh-state",
+      "type": "directory",
+      "mode": "0755",
+      "place": "mesh"
+    },
+    {
+      "id": "interpreter",
+      "type": "package",
+      "package": "nodejs"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "runtime",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/node-tools",
+        "binary": "node-tools"
+      }
+    ]
+  }
+}

node-tools/package-lock.json

@@ -0,0 +1,76 @@
+{
+  "name": "@novox/mesh-tools",
+  "version": "0.1.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "@novox/mesh-tools",
+      "version": "0.1.0",
+      "dependencies": {
+        "@novox/mesh-sdk": "^0.1.0",
+        "nats": "^2.29.0"
+      },
+      "bin": {
+        "mesh": "dist/mesh.js",
+        "mesh-tools": "dist/main.js"
+      },
+      "devDependencies": {
+        "@types/node": "^22.20.1",
+        "typescript": "^5.9.3"
+      }
+    },
+    "node_modules/@novox/mesh-sdk": {
+      "version": "0.1.1"
+    },
+    "node_modules/@types/node": {
+      "version": "22.20.1",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~6.21.0"
+      }
+    },
+    "node_modules/nats": {
+      "version": "2.29.3",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "nkeys.js": "1.1.0"
+      },
+      "engines": {
+        "node": ">= 14.0.0"
+      }
+    },
+    "node_modules/nkeys.js": {
+      "version": "1.1.0",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "tweetnacl": "1.0.3"
+      },
+      "engines": {
+        "node": ">=10.0.0"
+      }
+    },
+    "node_modules/tweetnacl": {
+      "version": "1.0.3",
+      "license": "Unlicense"
+    },
+    "node_modules/typescript": {
+      "version": "5.9.3",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=14.17"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "6.21.0",
+      "dev": true,
+      "license": "MIT"
+    }
+  }
+}

node-tools/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "@novox/mesh-tools",
+  "version": "0.1.0",
+  "description": "The Novox Mesh tool runtime \u2014 binds the mesh broker and serves the assigned modules' tools.",
+  "type": "module",
+  "bin": {
+    "mesh-tools": "./dist/main.js",
+    "mesh": "./dist/mesh.js"
+  },
+  "scripts": {
+    "build": "tsc",
+    "pretest": "tsc",
+    "test": "node --test --test-concurrency=1 --experimental-strip-types 'test/*.test.ts'"
+  },
+  "dependencies": {
+    "@novox/mesh-sdk": "^0.1.6",
+    "nats": "^2.29.0"
+  },
+  "devDependencies": {
+    "@types/node": "^22.20.1",
+    "typescript": "^5.9.3",
+    "esbuild": "^0.25.0",
+    "mongodb": "^6.21.0",
+    "mssql": "^11.0.2",
+    "pg": "^8"
+  }
+}

node-tools/src/announce.ts

@@ -0,0 +1,139 @@
+// What a runtime serves, it announces (novox/hq ADR 0197): the NATS services protocol's discovery —
+// `$SRV.PING`, `$SRV.INFO`, `$SRV.STATS`, and the same followed by the service's name and its id —
+// answered in the io.nats.micro.v1 format with what is served at the moment of the request. Serving is
+// unchanged; this only says what is served. One service per runtime process, because the bus admits
+// one reply per request from each responder: one endpoint per tool per subject, its metadata saying
+// which module, seat, scope and machine it is. The same shape the Go runtime answers.
+
+import { StringCodec } from "nats";
+import { asSchema } from "@novox/mesh-sdk/stdio";
+import type { ToolDefinition } from "@novox/mesh-sdk/tools";
+import type { RuntimeBroker } from "./broker-nats.js";
+
+const sc = StringCodec();
+
+export const VERSION = "0.1.0";
+export const INFO_RESPONSE = "io.nats.micro.v1.info_response";
+export const PING_RESPONSE = "io.nats.micro.v1.ping_response";
+export const STATS_RESPONSE = "io.nats.micro.v1.stats_response";
+
+/** One tool served on one subject, as announced. */
+export interface Endpoint {
+  kind: "tool" | "seat";
+  module: string;
+  tool: string;
+  seat?: string;
+  scope?: "mesh" | "node";
+  node: string;
+  description: string;
+  schema: unknown;
+  interchangeable: boolean;
+  subject: string;
+  queue?: string;
+}
+
+/** A seat's verb as the runtime serves it, with the definition that answers it. */
+export interface ServedSeatVerb {
+  seat: string;
+  verb: string;
+  subject: string;
+  holder: string;
+  tool: ToolDefinition;
+}
+
+export interface Service {
+  name: string;
+  id: string;
+  description: string;
+  metadata: Record<string, string>;
+}
+
+/** The endpoint's name as the protocol allows it; the metadata, not the name, identifies it. */
+function nameOf(e: Endpoint): string {
+  const clean = (s: string) => s.replace(/[^A-Za-z0-9_-]/g, "_");
+  return `${clean(e.kind === "seat" ? e.seat ?? "" : e.module)}__${clean(e.tool)}`;
+}
+
+/** The info_response for these endpoints. */
+export function info(s: Service, endpoints: Endpoint[]): Record<string, unknown> {
+  return {
+    name: s.name, id: s.id, version: VERSION, metadata: s.metadata, type: INFO_RESPONSE, description: s.description,
+    endpoints: endpoints.map((e) => {
+      const metadata: Record<string, string> = {
+        kind: e.kind, module: e.module, tool: e.tool, node: e.node, description: e.description,
+        schema: JSON.stringify(e.schema ?? {}), interchangeable: e.interchangeable ? "true" : "false",
+      };
+      if (e.kind === "seat") {
+        metadata.seat = e.seat ?? "";
+        metadata.scope = e.scope ?? "mesh";
+      }
+      return { name: nameOf(e), subject: e.subject, queue_group: e.queue ?? "", metadata };
+    }),
+  };
+}
+
+/** Everything served now: each module's tools on every subject issued for them, and each held
+ *  seat's verbs on the seat's subject. */
+export function endpointsOf(
+  broker: RuntimeBroker,
+  own: { module: string; tools: ToolDefinition[] }[],
+  seats: ServedSeatVerb[],
+): Endpoint[] {
+  const node = broker.node ?? "";
+  const out: Endpoint[] = [];
+  for (const { module, tools } of own) {
+    for (const t of tools) {
+      const served = broker.servedOn ? broker.servedOn(module, t.name) : [];
+      const interchangeable = served.some((s) => s.subject === `mesh.mod.${module}.tool.${t.name}`);
+      for (const s of served) {
+        out.push({ kind: "tool", module, tool: t.name, node, description: t.description, schema: asSchema(t.input),
+          interchangeable, subject: s.subject, queue: s.queue });
+      }
+    }
+  }
+  for (const v of seats) {
+    out.push({ kind: "seat", module: v.holder, tool: v.verb, seat: v.seat,
+      scope: node && v.subject.endsWith(`.${node}`) ? "node" : "mesh", node, description: v.tool.description,
+      schema: asSchema(v.tool.input), interchangeable: false, subject: v.subject });
+  }
+  return out;
+}
+
+/** Answer discovery for one service until stopped. */
+export function announce(broker: RuntimeBroker, s: Service, current: () => Endpoint[]): () => void {
+  const started = new Date().toISOString();
+  const identity = { name: s.name, id: s.id, version: VERSION, metadata: s.metadata };
+  const answer = (subject: string): Uint8Array | undefined => {
+    const parts = subject.split(".");
+    if (parts[0] !== "$SRV" || parts.length < 2) return undefined;
+    if (parts.length >= 3 && parts[2] !== s.name) return undefined; // another service's
+    if (parts.length >= 4 && parts[3] !== s.id) return undefined; // another instance's
+    let v: unknown;
+    switch (parts[1]) {
+      case "PING":
+        v = { ...identity, type: PING_RESPONSE };
+        break;
+      case "INFO":
+        v = info(s, current());
+        break;
+      case "STATS":
+        v = { ...identity, type: STATS_RESPONSE, started, endpoints: current().map((e) => ({
+          name: nameOf(e), subject: e.subject, queue_group: e.queue ?? "", num_requests: 0, num_errors: 0,
+          last_error: "", processing_time: 0, average_processing_time: 0 })) };
+        break;
+      default:
+        return undefined;
+    }
+    return sc.encode(JSON.stringify(v));
+  };
+  const stops: (() => void)[] = [];
+  // Exactly the questions asked of every service and of this one by name and instance — what the
+  // grants allow (novox/hq ADR 0197). A wildcard is refused by the bus, and a refused subscription
+  // ends a runtime: on 2026-10-03 it crash-looped every container that announced itself.
+  for (const verb of ["PING", "INFO", "STATS"]) {
+    for (const subject of [`$SRV.${verb}`, `$SRV.${verb}.${s.name}`, `$SRV.${verb}.${s.name}.${s.id}`]) {
+      stops.push(broker.raw!(subject, (subj) => answer(subj)));
+    }
+  }
+  return () => stops.forEach((stop) => stop());
+}

node-tools/src/broker-nats.ts

@@ -0,0 +1,680 @@
+// The tool runtime's broker client, on NATS.
+//
+// **The sdk's contract does not change** (novox/hq ADR 0106, ADR 0039): a module is written
+// against `request`, `handle`, `publish`, `subscribe`, `close`, and the runtime implements them.
+// That is why a module built before any of this runs on the new runtime without a rebuild, and
+// why the sdk's own diff for the whole bus change is three comments.
+//
+// Underneath, everything is a subject and durability is JetStream (novox/hq design 25,
+// design 29).
+//
+//   mesh.mod.<module>.event.<type>   an event this module emits
+//   mesh.mod.<module>.tool.<tool>    a tool this module serves
+//   mesh.seat.<seat>.accept.<verb>   work submitted to a role
+//
+// The module never writes one of those: it names its events and tools locally and the mesh
+// derives the subject (design 29 §1), so reorganising the subject space leaves every module
+// correct.
+
+import { AsyncLocalStorage } from "node:async_hooks";
+import { createHash } from "node:crypto";
+import net from "node:net";
+import tls from "node:tls";
+import { connect as natsConnect, headers as natsHeaders, StringCodec, type JsMsg, type Subscription, type TlsOptions } from "nats";
+import type { Broker, Envelope, EventHeaders } from "@novox/mesh-sdk/messaging";
+
+const sc = StringCodec();
+
+/** Requests wait this long for an answer before failing. Unchanged from what modules already
+ *  expect, so a module's timeout handling is not something the bus quietly redefines. */
+const REQUEST_TIMEOUT_MS = 30_000;
+
+export class PinMismatchError extends Error {}
+
+/** A broker credential as the mesh delivers it (novox/hq ADR 0120): the bus's address, the
+ *  fingerprint of the certificate it must present, and the node and module the account is scoped
+ *  to — the runtime derives its subjects from those rather than being told them. */
+export interface Credential {
+  url: string;
+  fingerprint?: string;
+  node?: string;
+  module?: string;
+  user?: string;
+  password?: string;
+  /** The seats this module claims, with the verbs each promises (novox/hq ADR 0159). The runtime
+   *  serves each claimed seat's verbs with its tools of the same name; the bus admits only the
+   *  holder's subscription, so claiming and not holding costs a refused subscription and nothing else. */
+  claims?: { seat: string; scope?: string; serves?: string[] }[];
+}
+
+/**
+ * What the mesh issued this assignment (novox/hq ADR 0160): where its tools are served, in which
+ * queue, the verbs of the seats it holds, where its events land, what it may reach. Read from the
+ * ASSIGNMENTS stream at `mesh.assignment.<node>.<module>` — the one subject a runtime derives for
+ * itself — and followed live. Absent for a mesh older than the membership, and then the runtime
+ * serves the shape it always derived, and says so.
+ */
+export interface Membership {
+  node: string;
+  module: string;
+  /** Addresses a tool is answered on; `{tool}` stands for the tool's name. */
+  serves: { subject: string; queue?: string }[];
+  seats?: { seat: string; verb: string; subject: string }[];
+  emits: string;
+  reaches?: Record<string, string[]>;
+  tools: string;
+}
+
+/** What a tool call answers: the module's own result, and which machine answered it
+ *  (novox/hq ADR 0159) — a module on several machines is otherwise an answer from nowhere. */
+export interface Answered<Res> {
+  result: Res;
+  node?: string;
+}
+
+/** The bus as the runtime sees it: the sdk's contract, and the few things only the runtime needs —
+ *  an answer that says which machine gave it, serving a subject that is not a module's own tool
+ *  (a seat's verb), and following the memberships of the modules it serves beside its own. */
+export interface RuntimeBroker extends Broker {
+  /** Call a tool by key, or — when `on` names a subject the mesh listed for it (ADR 0160) — there. */
+  ask<Req, Res>(key: string, body: Req, on?: string): Promise<Answered<Res>>;
+  handleSubject<Req, Res>(subject: string, handler: (body: Req) => Promise<Res>): Promise<() => void>;
+  /**
+   * Serve another module's tools from this connection: read its membership on this machine and
+   * follow it, so `handle("<module>.<tool>")` is served where the mesh issued that module (novox/hq
+   * ADR 0175: one runtime per node, every assigned module's tools). The account must be allowed
+   * to read that membership and to subscribe its subjects — the node's is; a module's own is not,
+   * and is refused by the bus, not here.
+   */
+  follow(module: string): Promise<void>;
+  /** What the mesh issued this assignment — this module's when none is named — or undefined when
+   *  nothing has been issued yet. */
+  membership(module?: string): Membership | undefined;
+  /** Called when the mesh issues a new membership to any module this connection follows; the
+   *  runtime re-serves on it. The membership says which module it is for. */
+  onMembership(handler: (m: Membership) => void): void;
+  /** The modules whose memberships this connection follows: its own and every one `follow` added. */
+  serving(): string[];
+  /** The module this connection is: what its credential named, and what a bare key serves as. */
+  readonly module: string;
+  /** Where a served module's tool is answered right now (ADR 0197: what it serves, it announces). */
+  servedOn?(module: string, tool: string): { subject: string; queue?: string }[];
+  /** Answer a subject in a format of its own, not a tool's reply envelope — the NATS services
+   *  protocol's discovery (novox/hq ADR 0197). An undefined answer is no reply. */
+  raw?(subject: string, answer: (subject: string, data: Uint8Array) => Uint8Array | undefined): () => void;
+  /** The machine this connection serves on, when its credential names one. */
+  readonly node?: string;
+}
+
+/**
+ * Which module's tool is at work on this connection, when one is (novox/hq ADR 0175). One runtime
+ * carries many modules' tools, and an event a tool emits must land on the emitting *module's*
+ * subject, not the runtime's — so the runtime runs each tool inside this store, and `publish`
+ * reads the module from it. Outside a tool the connection's own module stands.
+ */
+export const atWork = new AsyncLocalStorage<{ module: string }>();
+
+const ASSIGNMENTS_STREAM = "ASSIGNMENTS";
+
+/** The one address a runtime derives for itself (ADR 0160). */
+export function membershipSubject(node: string, module: string): string {
+  return `mesh.assignment.${node}.${module}`;
+}
+
+/** Whether a connection failure is worth retrying, or is a fact about this configuration that
+ *  retrying cannot change. The runtime's supervisor asks this and does not need to know what it
+ *  is connected to. */
+export function fatalBrokerReason(err: unknown): string | null {
+  if (err instanceof PinMismatchError) return "the bus's certificate does not match the pin";
+  const e = err as { code?: string; message?: string };
+  const message = typeof e?.message === "string" ? e.message : String(err);
+  if (e?.code === "ERR_INVALID_URL" || /invalid url/i.test(message)) {
+    return "the bus address is not a usable URL";
+  }
+  if (/authorization violation|user authentication expired|permissions violation/i.test(message)) {
+    return "the bus refused this account";
+  }
+  return null;
+}
+
+/**
+ * Connect to the mesh bus and return a Broker.
+ *
+ * **A module's subjects come from its credential, not from its calls.** `node` and `module` name
+ * the account the mesh issued, and every subject this client publishes or subscribes is derived
+ * from them — so a module cannot name another's namespace even by mistake, and what it emits
+ * matches what the mesh authorised (ADR 0074's identity rule).
+ */
+export async function connectNats(
+  target: string | Credential,
+  opts: { module?: string } = {},
+): Promise<RuntimeBroker> {
+  const cred: Credential = typeof target === "string" ? { url: target } : target;
+  const self = cred.module ?? opts.module;
+  if (!self) {
+    throw new Error(
+      "a broker credential with no module: the runtime derives its subjects from the account " +
+        "the mesh issued, and cannot guess which module it is",
+    );
+  }
+
+  const conn = await natsConnect({
+    servers: cred.url,
+    user: cred.user,
+    pass: cred.password,
+    name: `${cred.node ?? "?"}.${self}`,
+    tls: cred.fingerprint ? await pinnedTls(cred.url, cred.fingerprint) : undefined,
+    // Its own inbox, not a random one: every user's inbox is private to it (design 25 §4), and the
+    // grant names `_INBOX.<user>.>` — a reply space the client invented would be refused, and with
+    // it every pull for the next message and every answer to a tool call.
+    inboxPrefix: cred.user ? `_INBOX.${cred.user}` : undefined,
+    // Reconnect forever: the bus being restarted is an upgrade, not a reason for every module on
+    // the mesh to exit. `close()` stays the only thing that ends the connection.
+    maxReconnectAttempts: -1,
+  });
+  const js = conn.jetstream();
+
+  const subs: Subscription[] = [];
+  // Every registration, and the one reader that dispatches to them. A module has one durable
+  // consumer; the loop belongs to the connection rather than to a subscription.
+  const listeners: { pattern: string; handler: (env: Envelope<unknown>) => Promise<void> }[] = [];
+  let reading: Awaited<ReturnType<Awaited<ReturnType<typeof js.consumers.get>>["consume"]>> | undefined;
+  let closed = false;
+
+  const node = cred.node;
+
+  // The memberships, one per module this connection serves, each read once and followed. A
+  // module's own runtime follows one, its own; the node's runtime follows one per assigned module
+  // (novox/hq ADR 0175) — the same subject shape, the same stream, read as many times as there are
+  // modules, and nothing on the bus learns a new shape for it. A direct get is one request on the
+  // stream's API, which is the whole of what an account may ask JetStream for a subject it is
+  // granted; a 404 is a mesh that has not issued one, which is a fact to say and not an error to
+  // retry.
+  const issued = new Map<string, Membership | undefined>();
+  const issuedHandlers: ((m: Membership) => void)[] = [];
+  const follow = async (module: string): Promise<void> => {
+    if (!node || issued.has(module)) return;
+    issued.set(module, undefined);
+    const subjectOfTheirs = membershipSubject(node, module);
+    try {
+      // The subject-addressed form of a direct get — the stream, then the subject, nothing in
+      // the body — because that is the one address the mesh grants this account on the
+      // stream's API; the body form asks the stream's root, which it may not.
+      const got = await conn.request(`$JS.API.DIRECT.GET.${ASSIGNMENTS_STREAM}.${subjectOfTheirs}`,
+        new Uint8Array(0), { timeout: 5_000 });
+      const status = got.headers?.code ?? 0;
+      if (status === 0 && got.data.length > 0) {
+        issued.set(module, JSON.parse(sc.decode(got.data)) as Membership);
+      }
+    } catch {
+      // Not readable here: an older mesh, a stream not yet asserted, or no grant. Said below.
+    }
+    if (!issued.get(module)) {
+      console.log(`[mesh-tools] no membership issued for ${module} on ${node} yet; serving the derived shape until one arrives`);
+    }
+    try {
+      const live = conn.subscribe(subjectOfTheirs);
+      subs.push(live);
+      void (async () => {
+        for await (const msg of live) {
+          try {
+            const m = JSON.parse(sc.decode(msg.data)) as Membership;
+            issued.set(module, m);
+            console.log(`[mesh-tools] ${module} on ${node} was issued a new membership; re-serving on it`);
+            for (const h of issuedHandlers) h(m);
+          } catch (err) {
+            console.log(`[mesh-tools] a membership arrived that is not one: ${err}`);
+          }
+        }
+      })();
+    } catch {
+      // A subscription this account may not make is a mesh older than the membership.
+    }
+  };
+  await follow(self);
+
+  /** The subjects a tool of a served module is served on: from that module's membership when
+   *  issued, derived otherwise (the shape the mesh issues on day one, so the two agree). */
+  const servedOn = (module: string, tool: string): { subject: string; queue?: string }[] => {
+    const m = issued.get(module);
+    if (m) {
+      const out = m.serves.map((s) => ({ subject: s.subject.replace("{tool}", tool), queue: s.queue }));
+      // The verb that lists what this module serves is answered on the mesh's plain address for it
+      // whatever the placement — one answer suffices, so a queue — and on this machine's beside it.
+      if (tool === "tools" && m.tools && !out.some((s) => s.subject === m.tools)) {
+        out.unshift({ subject: m.tools, queue: `serve.${module}` });
+      }
+      return out;
+    }
+    const base = `mesh.mod.${module}.tool.${tool}`;
+    const out: { subject: string; queue?: string }[] = [{ subject: base, queue: `serve.${module}` }];
+    if (node) out.push({ subject: `${base}.${node}` });
+    return out;
+  };
+
+  /** Where a call by key goes: a subject this connection's own membership says it reaches, when it
+   *  says one — the machine's when named — else the derived shape. */
+  const reachedAt = (key: string): string => {
+    const [name, wanted] = key.split("@", 2);
+    const reach = issued.get(self)?.reaches?.[name];
+    if (reach && reach.length > 0) {
+      if (wanted) {
+        const at = reach.find((s) => s.endsWith(`.${wanted}`));
+        if (at) return at;
+      } else {
+        return reach[0];
+      }
+    }
+    return toolSubject(key, self);
+  };
+
+  /** Answer one subject with one handler, and say which machine answered (novox/hq ADR 0159). */
+  const answerOn = <Req, Res>(
+    subject: string,
+    queue: string | undefined,
+    handler: (body: Req) => Promise<Res>,
+  ): (() => void) => {
+    const sub = conn.subscribe(subject, queue ? { queue } : {});
+    subs.push(sub);
+    void (async () => {
+      // **A refused subscription is said, never fatal** (novox/hq 04-ISSUES/218, as 217 for the
+      // announcements). The grants are the mesh's word on what this account may answer; a subject
+      // they leave out — a seat claimed here and held elsewhere — costs that subject, never the
+      // module's other tools, its handlers and its provisioning. Unhandled, the refusal ended the
+      // process and a module's runtime crash-looped on 2026-10-04.
+      try {
+        for await (const msg of sub) {
+          let reply: { result?: Res; error?: string; node?: string };
+          try {
+            reply = { result: await handler(JSON.parse(sc.decode(msg.data)) as Req) };
+          } catch (err) {
+            // The caller is told, rather than left to time out: a handler that threw is a
+            // different failure from a tool nobody serves, and only one of them is worth retrying.
+            reply = { error: err instanceof Error ? err.message : String(err) };
+          }
+          if (node) reply.node = node;
+          msg.respond(sc.encode(JSON.stringify(reply)));
+        }
+      } catch (err) {
+        console.log(`[mesh-tools] the bus refused ${subject}: ${err instanceof Error ? err.message : String(err)}; ` +
+          "not served here, and the rest serves on");
+      }
+    })();
+    return () => sub.unsubscribe();
+  };
+
+  /**
+   * Ask one question and await one answer, with the machine that gave it.
+   *
+   * Core NATS request/reply, not JetStream: a tool call must never be persisted (design 25 §3),
+   * and a lost one is a timeout the caller already handles. The reply travels on the inbox the
+   * request carries, which the responder may answer because its account has `allow_responses`
+   * — one reply to a message it actually received, and nothing wider.
+   */
+  const ask = async <Req, Res>(key: string, body: Req, on?: string): Promise<Answered<Res>> => {
+    const msg = await conn.request(on ?? reachedAt(key), sc.encode(JSON.stringify(body)), {
+      timeout: REQUEST_TIMEOUT_MS,
+    });
+    const reply = JSON.parse(sc.decode(msg.data)) as { result?: Res; error?: string; node?: string };
+    if (reply.error) throw new Error(reply.error);
+    return { result: reply.result as Res, node: reply.node };
+  };
+
+  return {
+    async request<Req, Res>(key: string, body: Req): Promise<Res> {
+      return (await ask<Req, Res>(key, body)).result;
+    },
+
+    ask,
+
+    /**
+     * Answer a question, two ways (novox/hq ADR 0159): on the module's subject in a queue group,
+     * so several machines may serve one tool and exactly one of them answers each call; and on the
+     * same subject with this machine as its last token, so a caller that names the machine reaches
+     * this instance and no other. A runtime that does not know its machine serves only the first,
+     * which is how it always behaved.
+     */
+    async handle<Req, Res>(key: string, handler: (body: Req) => Promise<Res>): Promise<() => void> {
+      // A seat's verb named outright is served on the seat's subject as given, for a holder that
+      // knows its role without a membership; everything else is a served module's own tool, served
+      // where the mesh issued that module (ADR 0160). A key naming a module this connection does
+      // not follow is not served here at all: a module serves its own tools, and the node's
+      // runtime those of the modules it was given (ADR 0175) — never a stranger's.
+      if (key.startsWith("seat:")) {
+        const stop = answerOn(toolSubject(key, self), undefined, handler);
+        return () => stop();
+      }
+      const dot = key.indexOf(".");
+      const module = dot < 0 ? self : key.slice(0, dot);
+      if (!issued.has(module) && module !== self) {
+        throw new Error(
+          `${self} cannot serve ${key}: a module serves its own tools, and a runtime those of the ` +
+            "modules it follows",
+        );
+      }
+      const tool = dot < 0 ? key : key.slice(dot + 1);
+      let stops = servedOn(module, tool).map((s) => answerOn(s.subject, s.queue, handler));
+      // When that module's new membership arrives, serve where it now says and stop serving where
+      // it no longer does.
+      issuedHandlers.push((m) => {
+        if (m.module !== module) return;
+        stops.forEach((stop) => stop());
+        stops = servedOn(module, tool).map((s) => answerOn(s.subject, s.queue, handler));
+      });
+      return () => stops.forEach((stop) => stop());
+    },
+
+    module: self,
+    node,
+    servedOn,
+    raw(subject: string, answer: (subject: string, data: Uint8Array) => Uint8Array | undefined): () => void {
+      const sub = conn.subscribe(subject);
+      subs.push(sub);
+      void (async () => {
+        // **A refusal here is said, never fatal** (novox/hq 04-ISSUES/217). This serves discovery —
+        // what the runtime says about itself — not the work; a bus that refuses it costs the mesh
+        // seeing this runtime, not the runtime's tools and handlers. Unhandled, the refusal ended the
+        // process and every per-module container crash-looped on 2026-10-03.
+        try {
+          for await (const msg of sub) {
+            const body = answer(msg.subject, msg.data);
+            if (body) msg.respond(body);
+          }
+        } catch (err) {
+          console.log(`[mesh-tools] the bus refused ${subject}: ${err instanceof Error ? err.message : String(err)}; ` +
+            "discovery will not see this runtime there, and it serves on");
+        }
+      })();
+      return () => sub.unsubscribe();
+    },
+    follow,
+    serving: () => [...issued.keys()],
+    membership: (module?: string) => issued.get(module ?? self),
+    onMembership: (handler: (m: Membership) => void) => {
+      issuedHandlers.push(handler);
+    },
+
+    async handleSubject<Req, Res>(subject: string, handler: (body: Req) => Promise<Res>): Promise<() => void> {
+      return answerOn(subject, undefined, handler);
+    },
+
+    /**
+     * Emit an event.
+     *
+     * Published into JetStream and awaited, so a publish the bus never accepted fails the emit
+     * rather than vanishing — at-least-once starts at the emitter, not only the consumer
+     * (ADR 0042).
+     *
+     * `msgID` is the event's own id, so a redelivery after a crash between publishing and
+     * acknowledging is de-duplicated by the server inside its window rather than seen twice.
+     */
+    async publish<T>(env: Envelope<T>): Promise<void> {
+      // **The body is the payload and the metadata rides as headers** (ADR 0042). That shape
+      // is what the conformance suite pins: an implementation that nested the whole envelope in
+      // the body would pass every one of its own tests and agree with nobody.
+      const meta = (env.headers ?? {}) as Record<string, string>;
+      const h = natsHeaders();
+      for (const [k, v] of Object.entries(meta)) {
+        if (v != null) h.set(k, String(v));
+      }
+      if (!meta["content-type"]) h.set("content-type", "application/json");
+      if (env.node) h.set("x-node", env.node);
+
+      // The emitting module's subject: the tool at work's when a served module's tool emits from
+      // the node's runtime (ADR 0175), this connection's own otherwise.
+      await js.publish(eventSubject(env.key, atWork.getStore()?.module ?? self), sc.encode(JSON.stringify(env.body)), {
+        headers: h,
+        // De-duplicated by the server inside its window, so a redelivery after a crash between
+        // publishing and acknowledging is not seen twice. Only the emitter can make this id.
+        msgID: meta["x-event-id"],
+      });
+    },
+
+    /**
+     * React to events.
+     *
+     * The durable consumer is the **controller's** to create, from what this module declared it
+     * consumes (design 29 §3) — this binds to it and never creates one. A runtime that created
+     * its own would be a module deciding its own delivery semantics, and its account cannot
+     * reach the JetStream API to do it anyway.
+     *
+     * **One consumer, one loop, however many patterns a module registers.** A module has exactly one
+     * durable consumer, so two loops reading it would each take half the messages — and a loop that
+     * received one its own pattern does not match acknowledges it, which is the right answer for a
+     * filter wider than anything registered and silent loss when it is another handler's. Every
+     * registration is therefore dispatched from one reader, and a message is acknowledged once every
+     * handler it is for has taken it.
+     */
+    async subscribe<T>(
+      pattern: string,
+      handler: (env: Envelope<T>) => Promise<void>,
+    ): Promise<() => void> {
+      const listener = { pattern, handler: handler as (env: Envelope<unknown>) => Promise<void> };
+      listeners.push(listener);
+      if (!reading) {
+        const durable = `${cred.node ?? "?"}_${self}`;
+        const consumer = await js.consumers.get("EVENTS", durable);
+        const messages = await consumer.consume();
+        reading = messages;
+        void (async () => {
+          for await (const msg of messages) {
+            await deliver(msg, listeners);
+          }
+        })();
+      }
+      return () => {
+        const at = listeners.indexOf(listener);
+        if (at >= 0) listeners.splice(at, 1);
+        if (listeners.length === 0 && reading) {
+          void reading.close();
+          reading = undefined;
+        }
+      };
+    },
+
+    async close(): Promise<void> {
+      if (closed) return;
+      closed = true;
+      for (const sub of subs) sub.unsubscribe();
+      // Drain rather than close: an in-flight reply is finished instead of dropped, which for a
+      // tool call is the difference between an answer and an unexplained timeout at the caller.
+      await conn.drain();
+    },
+  };
+}
+
+/**
+ * Deliver one event to every handler it is for, acknowledging only once each has taken it.
+ *
+ * Several registrations share one durable consumer, so matching happens here rather than by having
+ * each registration read the stream: two readers of one consumer would split it between them, and a
+ * message that reached the wrong one would be acknowledged as not-for-me and lost.
+ */
+async function deliver(
+  msg: JsMsg,
+  listeners: { pattern: string; handler: (env: Envelope<unknown>) => Promise<void> }[],
+): Promise<void> {
+  let env: Envelope<unknown>;
+  try {
+    env = toEnvelope<unknown>(msg);
+  } catch {
+    // Unparseable: terminate it. Redelivering a message no version of this code can read is
+    // an infinite loop, and what the controller keeps of a message given up on (DEAD_LETTERS,
+    // novox/hq issue 330) is for handlers that fail, not for bytes that were never an envelope.
+    msg.term();
+    return;
+  }
+  const forThis = listeners.filter((l) => topicMatches(l.pattern, env.key));
+  if (forThis.length === 0) {
+    // The consumer's filters are the controller's, derived from what the module declared it
+    // consumes, and may be wider than anything it registered a handler for. Acknowledge it, or it
+    // would be redelivered until it expired.
+    msg.ack();
+    return;
+  }
+  try {
+    for (const l of forThis) await l.handler(env);
+    msg.ack();
+  } catch {
+    // Negative-acknowledge with a delay, so a handler failing on a transient cause gets another
+    // attempt, and one failing permanently exhausts max-deliver rather than spinning: the consumer
+    // gives the event up, and the controller keeps it in DEAD_LETTERS until a person delivers it
+    // again or drops it (novox/hq issue 330). Delivered again, it arrives under
+    // `mesh.again.<consumer>.…`, and keyFromSubject reads the same key from it. The consumer's
+    // limits are the controller's; this only says "not done".
+    msg.nak(5_000);
+  }
+}
+
+/** Rebuild the envelope a module sees, from the subject, the headers and the payload — the
+ *  mirror of publish, and the reason both live beside each other. */
+function toEnvelope<T>(msg: JsMsg): Envelope<T> {
+  const headers: Record<string, string> = {};
+  if (msg.headers) {
+    for (const k of msg.headers.keys()) headers[k] = msg.headers.get(k);
+  }
+  return {
+    // The event's own key, recovered from the subject: `mesh.mod.<module>.event.<key>`. The
+    // module never sees the subject, only the key it declared.
+    key: keyFromSubject(msg.subject),
+    node: headers["x-node"] ?? "",
+    body: JSON.parse(sc.decode(msg.data)) as T,
+    headers: headers as EventHeaders,
+  };
+}
+
+/** The event key a module sees: the emitter and the event, which is exactly how its manifest names
+ *  what it consumes (novox/hq design 29 §1, 04-ISSUES/127).
+ *
+ *  **One vocabulary for the declaration and the handler.** This returned the event name alone, so a
+ *  manifest declaring `consumes: builder.built` produced a handler pattern that could never match
+ *  the key it was compared against — and a module consuming the same event from two emitters could
+ *  not tell them apart except by reading a header. The subject already carries the emitter; naming it
+ *  here makes a mismatch between manifest and code a typo rather than a category error. */
+function keyFromSubject(subject: string): string {
+  const marker = ".event.";
+  const at = subject.indexOf(marker);
+  if (at < 0) return subject;
+  const event = subject.slice(at + marker.length);
+  // `mesh.mod.<emitter>.event.…` — the emitter is the token before the marker.
+  const before = subject.slice(0, at).split(".");
+  const emitter = before[before.length - 1];
+  return emitter ? `${emitter}.${event}` : event;
+}
+
+/** A module's own event subject. Derived, never taken from the caller: the module names its
+ *  event and the mesh decides where it lands (design 29 §1). */
+function eventSubject(type: string, self: string): string {
+  return `mesh.mod.${self}.event.${type}`;
+}
+
+/** A tool's subject. A bare name is this module's own tool; `<module>.<tool>` addresses
+ *  another's, which is how a request reaches a module that is not this one; `seat:<seat>.<verb>`
+ *  addresses a role's tool, answered by whoever holds the seat (novox/hq ADR 0132) — with
+ *  `seat:<seat>.<verb>@<node>` for a node-scoped seat, whose tool carries the machine (design 33 §4). */
+function toolSubject(key: string, self: string): string {
+  if (key.startsWith("seat:")) {
+    const rest = key.slice("seat:".length);
+    const dot = rest.indexOf(".");
+    if (dot < 0) throw new Error(`"${key}" names a seat and no verb: seat:<seat>.<verb>`);
+    const seat = rest.slice(0, dot);
+    const [verb, node] = rest.slice(dot + 1).split("@", 2);
+    return node ? `mesh.seat.${seat}.tool.${verb}.${node}` : `mesh.seat.${seat}.tool.${verb}`;
+  }
+  // `<module>.<tool>@<node>` names the machine (novox/hq ADR 0159): the same subject with the
+  // machine as its last token, which is what that instance serves beside the queue.
+  const [name, node] = key.split("@", 2);
+  const dot = name.indexOf(".");
+  const base = dot < 0
+    ? `mesh.mod.${self}.tool.${name}`
+    : `mesh.mod.${name.slice(0, dot)}.tool.${name.slice(dot + 1)}`;
+  return node ? `${base}.${node}` : base;
+}
+
+/** A seat's verb, as its holder serves it: flat for a mesh seat, carrying the machine for a
+ *  node-scoped one (design 33 §4) — the same shape the controller grants. */
+export function seatToolSubject(seat: string, verb: string, scope: string | undefined, node: string | undefined): string {
+  const base = `mesh.seat.${seat}.tool.${verb}`;
+  return scope === "node" && node ? `${base}.${node}` : base;
+}
+
+function normalizeFingerprint(fingerprint: string): string {
+  return fingerprint.replace(/^sha256:/i, "").replace(/:/g, "").toLowerCase();
+}
+
+/**
+ * Dial once to see the certificate, and refuse unless it is exactly the one the mesh pinned.
+ * A certificate authority is not consulted: the mesh issued this and knows its fingerprint,
+ * which is stronger than trusting whoever a machine's trust store happens to contain.
+ *
+ * **The pin is the only check.** What comes back is handed to the client as its TLS options, and
+ * the client's transport spreads them into Node's own `tls.connect` — so the pinned certificate
+ * is the one authority the handshake accepts, and the hostname check beside it is replaced with
+ * one that always passes. Pinning the exact certificate makes verifying its name redundant, and
+ * the bus's certificate names the seat (`mesh-broker`), not the address a machine happens to
+ * dial it by: every module on the mesh met "does not match certificate's altnames" the first time
+ * it reached the handshake (2026-09-28).
+ */
+async function pinnedTls(rawUrl: string, fingerprint: string): Promise<TlsOptions> {
+  const url = new URL(rawUrl.includes("://") ? rawUrl : `nats://${rawUrl}`);
+  const port = url.port ? Number(url.port) : 4222;
+  // **The bus speaks first, in the clear.** A NATS server sends its INFO line before TLS begins,
+  // and only then expects the client to start the handshake; a raw TLS connect to that port reads
+  // the INFO line as a TLS record and fails with "wrong version number" — which is what every
+  // module met the first time it dialled the bus being built (2026-09-28). So: connect, wait for
+  // INFO, then start TLS on the same socket, and read the certificate the server presents.
+  const certificate = await new Promise<tls.DetailedPeerCertificate>((resolve, reject) => {
+    const plain = net.connect({ host: url.hostname, port }, () => {});
+    let seenInfo = false;
+    let buffered = "";
+    plain.on("error", reject);
+    plain.on("data", (chunk: Buffer) => {
+      if (seenInfo) return;
+      buffered += chunk.toString("utf8");
+      if (!buffered.includes("\r\n")) return;
+      seenInfo = true;
+      plain.removeAllListeners("data");
+      const secure = tls.connect(
+        { socket: plain, rejectUnauthorized: false, servername: url.hostname },
+        () => {
+          const peer = secure.getPeerCertificate(true);
+          secure.end();
+          resolve(peer);
+        },
+      );
+      secure.on("error", reject);
+    });
+  });
+  const seen = createHash("sha256").update(certificate.raw).digest("hex");
+  if (seen !== normalizeFingerprint(fingerprint)) {
+    throw new PinMismatchError(
+      `the bus at ${url.hostname}:${port} presented ${seen}, not the pinned ${normalizeFingerprint(fingerprint)}`,
+    );
+  }
+  const pem = `-----BEGIN CERTIFICATE-----\n${certificate.raw.toString("base64").replace(/(.{64})/g, "$1\n")}\n-----END CERTIFICATE-----\n`;
+  // Node's option, not the client's: the transport passes the whole object on. `undefined` from
+  // checkServerIdentity is "the name is fine"; the pin above already decided the rest.
+  return { ca: pem, checkServerIdentity: () => undefined } as TlsOptions;
+}
+
+/** The mesh's topic matching: `*` is one token, `#` the rest. This is the module's vocabulary —
+ *  a module's `consumes` pattern is matched here, and the subject it becomes is the mesh's
+ *  business, not the module's. */
+export function topicMatches(pattern: string, key: string): boolean {
+  return matchFrom(pattern.split("."), 0, key.split("."), 0);
+}
+
+function matchFrom(p: string[], pi: number, k: string[], ki: number): boolean {
+  if (pi === p.length) return ki === k.length;
+  // `**` is the mesh's wildcard for the rest of a name; `#` is the old bus's, accepted so a pattern
+  // written either way behaves the same while both buses ship (novox/hq design 29 §1).
+  if (p[pi] === "#" || p[pi] === "**") {
+    for (let skip = ki; skip <= k.length; skip++) {
+      if (matchFrom(p, pi + 1, k, skip)) return true;
+    }
+    return false;
+  }
+  if (ki === k.length) return false;
+  if (p[pi] !== "*" && p[pi] !== k[ki]) return false;
+  return matchFrom(p, pi + 1, k, ki + 1);
+}

node-tools/src/client.ts

@@ -0,0 +1,280 @@
+/**
+ * The mesh's tools, for whoever is on a machine (novox/hq design 25 §7, design 34).
+ *
+ * Two surfaces over one thing. A command line, for somebody at a terminal; an MCP server, for an
+ * agent. Both are adapters over the same three calls — what tools are there, what does this one take,
+ * call it — because a second way of reaching a tool is a second thing to keep correct.
+ *
+ * **It uses the same client a module's runtime uses.** Not a second protocol and not a bridge: the
+ * caller connects as its own bus user — a person's, or the console's — publishes on the tool subjects
+ * that account permits, and the server refuses anything else. So "what may this ask" is answered by the
+ * same permission list that answers it for a module, and there is nothing here for an audit to read
+ * separately.
+ *
+ * What the caller may NOT do is the more interesting half, and none of it is enforced here — it is the
+ * account (design 25 §4): it cannot publish an event, so it cannot claim a module said something; it
+ * has no consumer, so there is no delivery to acknowledge; and it cannot answer a request, so it cannot
+ * impersonate a module on a bus where anyone may serve a tool.
+ */
+import { readFile } from "node:fs/promises";
+
+import type { Broker } from "@novox/mesh-sdk/messaging";
+
+import { connectNats, type Answered, type Credential } from "./broker-nats.js";
+import { TOOLS_VERB, type ToolsAnswer } from "./runtime.js";
+
+/** Where the catalogue answers which modules the mesh holds. */
+const CATALOGUE_MODULES = "mesh-catalog.catalog_modules";
+
+/** Where the mesh answers every role's tools, from its records: the mesh-controller seat's own
+ *  `tools` verb (novox/hq ADR 0154, design 33 §5). */
+const SEAT_TOOLS = "seat:mesh-controller.tools";
+
+/** A tool as its module describes it. */
+export interface Tool {
+  /** The module that serves it — or, for a role's tool, the seat. */
+  module: string;
+  name: string;
+  description?: string;
+  /** The JSON schema of what it takes, as the module declared it. */
+  input?: unknown;
+  /** True for a role's tool: addressed to the seat, answered by whoever holds it (ADR 0132). */
+  seat?: boolean;
+  /** A role's scope: `node` for a seat held once per machine, whose verb is asked of one machine
+   *  (design 33 §4) and takes `node` for it; `mesh` or absent otherwise. */
+  scope?: string;
+  /** Where the tool is answered, as the mesh issued it (ADR 0160): the plain subject first when the
+   *  module answers for itself anywhere, then one per machine. Absent for a runtime older than this. */
+  subjects?: string[];
+}
+
+/**
+ * What the mesh could say about its tools when asked (design 34 §3).
+ *
+ * **Silence is named, never dropped.** A module the catalogue holds and nothing answered for is in
+ * `notAnswering`, because a tool that is not offered looks exactly like a tool that does not exist,
+ * and those need different people to fix them.
+ */
+export interface Listing {
+  tools: Tool[];
+  /** Modules the catalogue holds whose runtime did not answer `tools`: not assigned, not up, or built
+   *  before the runtime answered it. Each may still be called by name. The mesh's own records are
+   *  listed here as `mesh-controller (seat)` when the control plane did not answer. */
+  notAnswering: string[];
+}
+
+/** The seats and the verbs each declares, from the last listing, so a call can tell a role's tool
+ *  from a module's when the two share a prefix (a module and a seat may share a name). */
+export type Seats = Map<string, Set<string>>;
+
+/** The roles' tools, keyed the way `toolKey` names them. */
+export function seatsIn(have: Listing): Seats {
+  const seats: Seats = new Map();
+  for (const t of have.tools) {
+    if (!t.seat) continue;
+    if (!seats.has(t.module)) seats.set(t.module, new Set());
+    seats.get(t.module)!.add(t.name);
+  }
+  return seats;
+}
+
+/** The key a call uses for `<prefix>.<name>`: a role's when the prefix is a seat declaring that
+ *  verb, a module's otherwise. Both names for one capability are deliberate and bounded (ADR 0132);
+ *  the seat wins only for a verb it actually declares, so a module's own tool is never shadowed. */
+export function toolKey(name: string, seats?: Seats): string {
+  if (name.startsWith("seat:")) return name;
+  const dot = name.indexOf(".");
+  if (dot < 0) return name;
+  const prefix = name.slice(0, dot);
+  const verb = name.slice(dot + 1);
+  if (seats?.get(prefix)?.has(verb)) return `seat:${prefix}.${verb}`;
+  return name;
+}
+
+/**
+ * A person's credential, as `operator issue` prints it.
+ *
+ * The same shape a module is handed, minus the parts a module needs and a person does not: no node,
+ * because a person is not on a machine, and no module, because they are not one.
+ */
+export interface PersonCredential extends Credential {
+  person?: string;
+  invokes?: string[];
+}
+
+/** Read the credential from the file `operator issue` produced. */
+export async function credentialFrom(path: string): Promise<PersonCredential> {
+  const raw = await readFile(path, "utf8");
+  let held: PersonCredential;
+  try {
+    held = JSON.parse(raw) as PersonCredential;
+  } catch (e) {
+    throw new Error(
+      `${path} is not a credential this mesh issued: ${(e as Error).message}. ` +
+        "It is the JSON `operator issue` printed, saved verbatim.",
+    );
+  }
+  if (!held.url || !held.user || !held.password) {
+    throw new Error(
+      `${path} names no bus, user or password. It is the JSON \`operator issue\` printed, saved ` +
+        "verbatim — not an edited copy of it.",
+    );
+  }
+  return held;
+}
+
+/** Connect as this person. The module name the runtime wants is their own user, because every subject
+ *  it derives is for a tool somebody else serves. */
+export async function connectAs(held: PersonCredential): Promise<Broker> {
+  return connectNats({ ...held, module: held.user });
+}
+
+/**
+ * Connect as the console: the module credential the mesh delivered (novox/hq ADR 0152), read from
+ * the same variable every runtime reads. It names the node and the module, so the account's inbox
+ * and subjects derive from what the mesh authorised and from nothing in this process's environment.
+ */
+export async function connectAsTheConsole(path: string): Promise<{ bus: Broker; who: string }> {
+  const raw = await readFile(path, "utf8");
+  let held: Credential;
+  try {
+    held = JSON.parse(raw) as Credential;
+  } catch (e) {
+    throw new Error(`${path} is not a broker credential: ${(e as Error).message}`);
+  }
+  if (!held.url || !held.module || !held.user) {
+    throw new Error(
+      `${path} names no bus, module or user: the console runs on the credential the mesh sealed to ` +
+        "this machine for it, and nothing else",
+    );
+  }
+  return { bus: await connectNats(held), who: `${held.node ?? "?"}.${held.module}` };
+}
+
+/**
+ * What tools the mesh has, asked of the modules (design 34 §3).
+ *
+ * The catalogue says which modules the mesh holds; each module says what it serves, through the one
+ * verb its runtime answers for it. **Asked, not configured**: a client carrying its own list would be a
+ * list that goes stale the first time a module is assigned. Every module is asked at once, and the bus
+ * refuses at once a request nothing serves, so the cost is bounded by the modules that are up.
+ */
+export async function toolsOn(bus: Broker): Promise<Listing> {
+  const [answered, roles] = await Promise.all([
+    bus.request<Record<string, never>, { modules?: { module: string }[] }>(CATALOGUE_MODULES, {}),
+    // The roles' tools, from the mesh's records (design 33 §5). Asked beside the modules rather
+    // than first: a control plane that is restarting must not hide every module's tools with it.
+    bus
+      .request<Record<string, never>, { seats?: { seat: string; scope?: string; tools?: ToolsAnswer["tools"] }[] }>(
+        SEAT_TOOLS,
+        {},
+      )
+      .catch(() => undefined),
+  ]);
+  const names = (answered.modules ?? []).map((m) => m.module).filter((m) => typeof m === "string");
+
+  const asked = await Promise.allSettled(
+    names.map((module) => bus.request<Record<string, never>, ToolsAnswer>(`${module}.${TOOLS_VERB}`, {})),
+  );
+  const tools: Tool[] = [];
+  const notAnswering: string[] = [];
+  if (roles) {
+    for (const s of roles.seats ?? []) {
+      // A node-scoped seat's tool is asked of one machine (design 33 §4): listed with its scope, so
+      // a caller names the machine and the call carries it — `seat:<seat>.<verb>@<node>`. Left out
+      // of the listing, the verb never resolved as a seat's and nothing served it (ADR 0170).
+      for (const t of s.tools ?? []) {
+        tools.push({ module: s.seat, name: t.name, description: t.description, input: t.input, seat: true, scope: s.scope });
+      }
+    }
+  } else {
+    notAnswering.push("mesh-controller (seat)");
+  }
+  asked.forEach((outcome, i) => {
+    const module = names[i]!;
+    if (outcome.status === "fulfilled" && typeof outcome.value?.failed === "string") {
+      // The runtime answered for it and serves nothing: the bundle failed to load (ADR 0175). Said
+      // with the reason, because "not answering" would send somebody to check an assignment that
+      // is fine.
+      notAnswering.push(`${module} (its tools bundle failed to load: ${outcome.value.failed})`);
+    } else if (outcome.status === "fulfilled" && Array.isArray(outcome.value?.tools)) {
+      for (const t of outcome.value.tools) {
+        tools.push({ module, name: t.name, description: t.description, input: t.input, subjects: t.subjects });
+      }
+    } else {
+      notAnswering.push(module);
+    }
+  });
+  tools.sort((a, b) => `${a.module}.${a.name}`.localeCompare(`${b.module}.${b.name}`));
+  notAnswering.sort();
+  return { tools, notAnswering };
+}
+
+/** Call one tool. The key is `<module>.<tool>`, which is what a person types and what the account
+ *  permits — one vocabulary, so a refusal names the thing they asked for. */
+/** Call a tool and learn which machine answered (novox/hq ADR 0159). `<module>.<tool>@<node>` asks
+ *  the instance on one machine; without it, whichever instance answers first does, and the answer
+ *  says which. */
+export async function callTool(
+  bus: Broker,
+  key: string,
+  args: unknown,
+  seats?: Seats,
+  listing?: Listing,
+): Promise<Answered<unknown>> {
+  const at = key.indexOf("@");
+  const name = at < 0 ? key : key.slice(0, at);
+  const node = at < 0 ? "" : key.slice(at + 1);
+  if (!name.includes(".")) {
+    throw new Error(
+      `"${key}" does not name a tool: write <module>.<tool>, as \`mesh tools\` lists them, ` +
+        "or <module>.<tool>@<node> for the instance on one machine",
+    );
+  }
+  const resolved = toolKey(name, seats) + (node ? `@${node}` : "");
+  // Where the tool is answered is the module's to say and the mesh's to issue (ADR 0160): when the
+  // listing carried subjects for it, the call goes to one of those and composes nothing.
+  const on = subjectListed(name, node, listing);
+  const asking = bus as Broker & { ask?: <Req, Res>(k: string, b: Req, on?: string) => Promise<Answered<Res>> };
+  if (typeof asking.ask === "function") return asking.ask<unknown, unknown>(resolved, args ?? {}, on);
+  return { result: await bus.request<unknown, unknown>(resolved, args ?? {}) };
+}
+
+/** The subject the listing says answers `<module>.<tool>` — the machine's when one is named, else
+ *  the plain one — or undefined when the listing said none, and the key is composed as before. */
+export function subjectListed(name: string, node: string, listing?: Listing): string | undefined {
+  if (!listing) return undefined;
+  const dot = name.indexOf(".");
+  const module = name.slice(0, dot);
+  const tool = name.slice(dot + 1);
+  const found = listing.tools.find((t) => t.module === module && t.name === tool && !t.seat);
+  const subjects = found?.subjects ?? [];
+  if (subjects.length === 0) return undefined;
+  if (node) return subjects.find((s) => s.endsWith(`.${node}`));
+  return subjects[0];
+}
+
+/**
+ * Why a call failed, said so that the remedy is in the words.
+ *
+ * Three answers a person actually gets, and they need different things done: nobody serves that tool,
+ * the mesh refused this account, or the tool itself failed. Without this they are one timeout and a
+ * stack trace.
+ */
+export function whyItFailed(key: string, err: unknown): string {
+  const message = err instanceof Error ? err.message : String(err);
+  if (/no responders|503/i.test(message)) {
+    return `nothing serves ${key}. The module may not be assigned to any machine, or it is down` +
+      (key.startsWith("seat:") ? ", or nothing holds that seat" : "") +
+      " — `mesh tools` lists what answered.";
+  }
+  if (/permissions violation|authorization/i.test(message)) {
+    return `this account may not call ${key}. What it may call was fixed when it was issued — a ` +
+      "person's by `operator issue`, the console's by its manifest.";
+  }
+  if (/timeout/i.test(message)) {
+    return `${key} did not answer in time. Something is serving it, so this is the tool being slow ` +
+      "rather than absent.";
+  }
+  return `${key} failed: ${message}`;
+}

node-tools/src/http.ts

@@ -0,0 +1,165 @@
+/**
+ * The console's endpoint: MCP over HTTP, on a machine's loopback (novox/hq ADR 0152, design 34 §2).
+ *
+ * **Loopback is the authority boundary.** Whoever can connect is on the machine, and whoever is on the
+ * machine is the account that owns the mesh there (ADR 0034, ADR 0144). So there is no token and no
+ * login here, and the one thing this file enforces is that it binds nothing else: a console reachable
+ * from another machine would be authority over the mesh handed to whoever finds the port.
+ *
+ * The transport is the streamable-HTTP shape an agent host speaks: `POST /mcp` with one JSON-RPC
+ * message, answered with one JSON body. No session, because the surface holds nothing per caller; no
+ * event stream, because nothing here has anything to say unasked.
+ */
+import { createServer, type IncomingMessage, type ServerResponse } from "node:http";
+
+import type { Broker } from "@novox/mesh-sdk/messaging";
+
+import { mcpSurface, type Reply, type Request } from "./mcp.js";
+
+/** The most a request body may be. A tool's arguments are small; a megabyte is somebody else's file. */
+const BODY_LIMIT = 1 << 20;
+
+export interface Listening {
+  /** Where it listens, as `host:port`, with the port the machine actually gave. */
+  address: string;
+  close(): Promise<void>;
+}
+
+/** Hosts that are this machine and no other. */
+const loopback = new Set(["127.0.0.1", "::1", "localhost", "[::1]"]);
+
+/**
+ * Listen on `host:port`. Refused unless the host is loopback — said before binding, so a manifest or
+ * a flag that would open the console to a network is a startup failure rather than something
+ * discovered by whoever finds it.
+ */
+export async function serveMcpHttp(bus: Broker, who: string, listen: string): Promise<Listening> {
+  const at = listen.lastIndexOf(":");
+  if (at < 0) {
+    throw new Error(`"${listen}" is not host:port`);
+  }
+  const host = listen.slice(0, at);
+  const port = Number(listen.slice(at + 1));
+  if (!loopback.has(host)) {
+    throw new Error(
+      `the console listens on loopback and nowhere else (novox/hq ADR 0152): "${host}" is not this ` +
+        "machine's own address — whoever is on the machine owns the mesh there, and nobody else may reach this",
+    );
+  }
+  if (!Number.isInteger(port) || port < 0 || port > 65535) {
+    throw new Error(`"${listen.slice(at + 1)}" is not a port`);
+  }
+
+  const surface = mcpSurface(bus, who);
+  const server = createServer((req, res) => {
+    void route(req, res, surface.handle).catch((e) => {
+      json(res, 500, { jsonrpc: "2.0", id: null, error: { code: -32603, message: String(e) } });
+    });
+  });
+
+  await new Promise<void>((resolve, reject) => {
+    server.once("error", reject);
+    server.listen(port, host.replace(/^\[|\]$/g, ""), () => resolve());
+  });
+  const bound = server.address();
+  const address = typeof bound === "object" && bound ? `${host}:${bound.port}` : listen;
+  return {
+    address,
+    close: () =>
+      new Promise<void>((resolve) => {
+        server.close(() => resolve());
+      }),
+  };
+}
+
+async function route(
+  req: IncomingMessage,
+  res: ServerResponse,
+  handle: (r: Request) => Promise<Reply | undefined>,
+): Promise<void> {
+  const path = (req.url ?? "/").split("?")[0];
+  if (path === "/") {
+    res.writeHead(200, { "content-type": "text/plain; charset=utf-8" });
+    res.end("the mesh's console: MCP over HTTP at POST /mcp (novox/hq design 34)\n");
+    return;
+  }
+  if (path !== "/mcp") {
+    json(res, 404, { error: "the console serves /mcp and nothing else" });
+    return;
+  }
+  switch (req.method) {
+    case "POST":
+      break;
+    case "DELETE":
+      // A host ending a session. There is no session to end; saying so is the truthful answer.
+      res.writeHead(204).end();
+      return;
+    case "GET":
+      // A host opening an event stream. The console has nothing to say unasked.
+      res.writeHead(405, { allow: "POST, DELETE" }).end();
+      return;
+    default:
+      res.writeHead(405, { allow: "POST, DELETE" }).end();
+      return;
+  }
+
+  let body: string;
+  try {
+    body = await read(req);
+  } catch (e) {
+    json(res, 413, { jsonrpc: "2.0", id: null, error: { code: -32600, message: String(e) } });
+    return;
+  }
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(body);
+  } catch {
+    json(res, 400, { jsonrpc: "2.0", id: null, error: { code: -32700, message: "the body is not JSON" } });
+    return;
+  }
+
+  // One message, or a batch of them; a batch is answered as a batch. A notification gets no reply
+  // and, alone, no body: 202 is how the transport says "heard".
+  if (Array.isArray(parsed)) {
+    const replies = (await Promise.all(parsed.map((r) => handle(r as Request)))).filter(Boolean);
+    if (replies.length === 0) {
+      res.writeHead(202).end();
+    } else {
+      json(res, 200, replies);
+    }
+    return;
+  }
+  const reply = await handle(parsed as Request);
+  if (!reply) {
+    res.writeHead(202).end();
+    return;
+  }
+  json(res, 200, reply);
+}
+
+function read(req: IncomingMessage): Promise<string> {
+  return new Promise((resolve, reject) => {
+    let size = 0;
+    const chunks: Buffer[] = [];
+    req.on("data", (chunk: Buffer) => {
+      size += chunk.length;
+      if (size > BODY_LIMIT) {
+        reject(new Error(`the request is larger than ${BODY_LIMIT} bytes`));
+        req.destroy();
+        return;
+      }
+      chunks.push(chunk);
+    });
+    req.on("end", () => resolve(Buffer.concat(chunks).toString("utf8")));
+    req.on("error", reject);
+  });
+}
+
+function json(res: ServerResponse, status: number, body: unknown): void {
+  const text = JSON.stringify(body);
+  res.writeHead(status, {
+    "content-type": "application/json; charset=utf-8",
+    "content-length": Buffer.byteLength(text),
+  });
+  res.end(text);
+}

node-tools/src/launch.ts

@@ -0,0 +1,192 @@
+// A tools bundle as a process the runtime launches (novox/hq ADR 0188).
+//
+// The runtime does not run a tool's code itself when the bundle is not JavaScript: it starts the
+// bundle's executable as a child with the runtime's environment and speaks MCP over stdio to it —
+// `initialize`, `tools/list` once, `tools/call` per call. A Rust binary, a Go binary, a Python
+// script and a Node script are the same thing from here: a process that answers those. Everything
+// the mesh adds — the subjects from the membership, the held seats, the `tools` answer, a bundle
+// that failed named and the others serving — is the runtime's, outside this file.
+//
+// A tool the child lists as `<seat>.<verb>` is the module's implementation of that seat's verb;
+// any other name is the module's own tool. The same rule the in-process registration follows.
+
+import { spawn, type ChildProcess } from "node:child_process";
+import { accessSync, constants } from "node:fs";
+import type { ToolDefinition } from "@novox/mesh-sdk/tools";
+import { broker, type Envelope } from "@novox/mesh-sdk/messaging";
+import { atWork } from "./broker-nats.js";
+
+/** The protocol version this speaks; a bundle says the same. */
+export const PROTOCOL = "2025-03-26";
+
+/** How long a child has to answer `initialize` and `tools/list` before it is a failed bundle, and
+ *  how long a call may take before the caller is told the tool is slow rather than absent. */
+const HANDSHAKE_MS = 10_000;
+const CALL_MS = 30_000;
+
+/** Whether an entrypoint is launched as a process rather than imported: anything that is not a
+ *  plain JavaScript file, and a JavaScript file marked executable — a bundle written against the
+ *  protocol in TypeScript, served the same way as any other language. */
+export function launches(entry: string): boolean {
+  const javascript = /\.(m|c)?js$/.test(entry);
+  let executable = false;
+  try {
+    accessSync(entry, constants.X_OK);
+    executable = true;
+  } catch {
+    // not executable, or not there — importing will say which
+  }
+  return !javascript || executable;
+}
+
+/** What a launched bundle registers: the groups the in-process path would have, by name. */
+export interface Launched {
+  registrations: { module: string; tools: ToolDefinition[] }[];
+  stop(): void;
+}
+
+interface Pending {
+  resolve(v: any): void;
+  reject(e: Error): void;
+  timer: NodeJS.Timeout;
+}
+
+/**
+ * Launch a bundle and learn its tools. Rejects when the child cannot be started or does not complete
+ * the handshake, which the runtime records as the bundle having failed. A child that exits later is
+ * started again on the next call, once; a call in flight when it died is told so.
+ */
+export async function launch(module: string, entry: string, env: NodeJS.ProcessEnv = process.env): Promise<Launched> {
+  let child: ChildProcess | undefined;
+  let nextId = 1;
+  const pending = new Map<number, Pending>();
+  let stopped = false;
+
+  const start = async (): Promise<void> => {
+    const proc = spawn(entry, [], { stdio: ["pipe", "pipe", "pipe"], env });
+    child = proc;
+    let buffered = "";
+    proc.stdout!.on("data", (chunk: Buffer) => {
+      buffered += chunk.toString("utf8");
+      let at: number;
+      while ((at = buffered.indexOf("\n")) >= 0) {
+        const line = buffered.slice(0, at).trim();
+        buffered = buffered.slice(at + 1);
+        if (!line) continue;
+        let reply: { id?: number | string; method?: string; params?: unknown; result?: unknown; error?: { message?: string } };
+        try {
+          reply = JSON.parse(line);
+        } catch {
+          console.log(`[mesh-tools] ${module}'s bundle said something that is not a reply: ${line.slice(0, 120)}`);
+          continue;
+        }
+        // **The bundle asks the runtime to emit** (novox/hq ADR 0193): published on the bus as this
+        // module, and answered once the bus has accepted it, so the tool's emit means what it means
+        // in-process. Nothing else a bundle may ask.
+        if (typeof reply.method === "string") {
+          const id = reply.id;
+          const answer = (m: Record<string, unknown>) => proc.stdin!.write(JSON.stringify({ jsonrpc: "2.0", id, ...m }) + "\n");
+          if (reply.method !== "mesh/publish") {
+            if (id !== undefined) answer({ error: { code: -32601, message: `the runtime answers no ${reply.method} from a bundle` } });
+            continue;
+          }
+          atWork.run({ module }, () => broker().publish(reply.params as Envelope<unknown>))
+            .then(() => { if (id !== undefined) answer({ result: {} }); })
+            .catch((err: unknown) => { if (id !== undefined) answer({ error: { code: -32000, message: err instanceof Error ? err.message : String(err) } }); });
+          continue;
+        }
+        const waiting = typeof reply.id === "number" ? pending.get(reply.id) : undefined;
+        if (!waiting) continue;
+        pending.delete(reply.id as number);
+        clearTimeout(waiting.timer);
+        if (reply.error) waiting.reject(new Error(reply.error.message ?? "the bundle refused the request"));
+        else waiting.resolve(reply.result);
+      }
+    });
+    // stderr is the bundle's log; kept under the module's name so a fault reads where it belongs.
+    // The last thing it said is kept, so a bundle that dies says why in its own words, not by code.
+    let lastSaid = "";
+    proc.stderr!.on("data", (chunk: Buffer) => {
+      for (const line of chunk.toString("utf8").split("\n")) {
+        if (!line.trim()) continue;
+        console.log(`[${module}] ${line}`);
+        if (/\S/.test(line) && !/^\s+at\s/.test(line) && !/^Node\.js v/.test(line)) lastSaid = line.trim();
+      }
+    });
+    const exited = new Promise<never>((_, reject) => {
+      proc.once("error", (err) => reject(err));
+      proc.once("exit", (code, signal) => {
+        const why = `${module}'s bundle exited (${signal ?? code})` + (lastSaid ? `: ${lastSaid}` : "");
+        for (const [id, p] of pending) {
+          pending.delete(id);
+          clearTimeout(p.timer);
+          p.reject(new Error(why));
+        }
+        if (child === proc) child = undefined;
+        if (!stopped) console.log(`[mesh-tools] ${why}; started again on its next call`);
+        reject(new Error(why));
+      });
+    });
+    const ask = (method: string, params: unknown, ms: number): Promise<any> =>
+      Promise.race([
+        new Promise<any>((resolve, reject) => {
+          const id = nextId++;
+          const timer = setTimeout(() => {
+            pending.delete(id);
+            reject(new Error(`${module}'s bundle did not answer ${method} in ${ms / 1000}s`));
+          }, ms);
+          pending.set(id, { resolve, reject, timer });
+          proc.stdin!.write(JSON.stringify({ jsonrpc: "2.0", id, method, params }) + "\n");
+        }),
+        exited,
+      ]);
+    exited.catch(() => {}); // observed through the race; never unhandled
+    (proc as ChildProcess & { ask?: typeof ask }).ask = ask;
+    await ask("initialize", { protocolVersion: PROTOCOL, capabilities: {}, clientInfo: { name: "node-tools", version: "1" } }, HANDSHAKE_MS);
+    proc.stdin!.write(JSON.stringify({ jsonrpc: "2.0", method: "notifications/initialized" }) + "\n");
+  };
+
+  const asking = async (method: string, params: unknown, ms: number): Promise<any> => {
+    if (!child) await start();
+    return (child as ChildProcess & { ask: (m: string, p: unknown, ms: number) => Promise<any> }).ask(method, params, ms);
+  };
+
+  await start();
+  const listed = (await asking("tools/list", {}, HANDSHAKE_MS)) as { tools?: { name: string; description?: string; inputSchema?: unknown }[] };
+  const groups = new Map<string, ToolDefinition[]>();
+  for (const t of listed.tools ?? []) {
+    const dot = t.name.indexOf(".");
+    const under = dot < 0 ? module : t.name.slice(0, dot);
+    const name = dot < 0 ? t.name : t.name.slice(dot + 1);
+    const tools = groups.get(under) ?? [];
+    tools.push({
+      name,
+      description: t.description ?? "",
+      input: (t.inputSchema as Record<string, unknown> | undefined) ?? {},
+      run: async (args) => {
+        const result = (await asking("tools/call", { name: t.name, arguments: args ?? {} }, CALL_MS)) as {
+          content?: { type: string; text?: string }[];
+          isError?: boolean;
+        };
+        const text = result?.content?.find((c) => c.type === "text")?.text ?? "";
+        if (result?.isError) throw new Error(text || `${module}.${t.name} failed`);
+        // The bundle's answer is JSON as text (that is what every MCP host renders); handed back as
+        // the value it encodes so a caller on the bus sees what an in-process tool would return.
+        try {
+          return JSON.parse(text);
+        } catch {
+          return text;
+        }
+      },
+    });
+    groups.set(under, tools);
+  }
+  return {
+    registrations: [...groups].map(([under, tools]) => ({ module: under, tools })),
+    stop: () => {
+      stopped = true;
+      child?.kill("SIGTERM");
+      child = undefined;
+    },
+  };
+}

node-tools/src/main.ts

@@ -1,10 +1,14 @@
 // The runnable entrypoint. Three modes:
 //
 //   mesh-tools                    serve — bind the broker and serve the assigned modules until
-//                                 stopped. A module entrypoint that subscribes to events (on("#"))
+//                                 stopped; as the node-tools module, also the console on loopback. A module entrypoint that subscribes to events (on("#"))
 //                                 starts consuming as it is imported, so this also runs consumers.
 //   mesh-tools emit TYPE [JSON]   emit one event onto the mesh and exit — an operable primitive,
 //                                 and what an events test uses to put a message on the wire.
+//   mesh-tools prepare            bring this module's state to the shape this version needs and exit
+//                                 — the runtime's answer to the word the mesh asks every module
+//                                 (novox/hq ADR 0135). The entrypoints come from MESH_PREPARE, which
+//                                 the module's own image names beside MESH_TOOL_MODULES.
 //   mesh-tools run ENTRYPOINT     run one compiled module entrypoint to completion and exit — the
 //                                 runtime side of a run-once step (novox/hq ADR 0052). It imports
 //                                 the given entrypoint, whose top-level code does its work — seed a
@@ -17,14 +21,19 @@
 //   MESH_BROKER_FILE   a sealed {url, fingerprint} the mesh delivered (novox/hq ADR 0043) — an
 //                      amqps account scoped to this module. Preferred: a module holds its own.
 //   MESH_BROKER_URL    a plain URL, for the bootstrap/admin case before a module has an account.
-//   MESH_TOOL_MODULES  /path/a,/path/b,…   compiled module entrypoints (serve mode)
+//   MESH_TOOL_MODULES  <module>=/path/a,…   the modules to serve and their compiled entrypoints (serve
+//                      mode; ADR 0175); a bare path is an entrypoint of the credential's own module
+//   MESH_PREPARE       /path/a,/path/b,…   compiled entrypoints that prepare this module's state
 //   MESH_MODULE / MESH_NODE                the identity stamped onto emitted events (ADR 0042)
 
 import { readFileSync } from "node:fs";
 import { pathToFileURL } from "node:url";
-import { connectAmqp, fatalBrokerReason } from "./broker-amqp.js";
+import { connectNats, fatalBrokerReason as fatalNatsReason, type Credential } from "./broker-nats.js";
-import type { Credential } from "./broker-amqp.js";
+import { takeToolEnvs, runTools, type ServedModule } from "./runtime.js";
-import { runTools } from "./runtime.js";
+import { serveMcpHttp, type Listening } from "./http.js";
+
+/** The credential this process connected with, for what it says beyond the connection (ADR 0159). */
+let lastCredential: Credential | undefined;
 import { invokeTool } from "@novox/mesh-sdk/tools";
 import { useBroker } from "@novox/mesh-sdk/messaging";
 import type { Broker } from "@novox/mesh-sdk/messaging";
@@ -35,12 +44,19 @@ import { emit } from "@novox/mesh-sdk/events";
  * over the plain bootstrap URL otherwise. A scoped module assumes the foundation's exchanges exist —
  * its account may not declare them (ADR 0043).
  */
+// fatalBrokerReasonFor is the reason a connection failure is final rather than "not yet", for
+// whichever bus this runtime is on — each transport knows its own refusals.
+function fatalBrokerReasonFor(err: unknown): string | null {
+  return fatalNatsReason(err);
+}
+
 async function connectBroker(): Promise<Broker> {
   const file = process.env.MESH_BROKER_FILE;
   if (file) {
     let credential: Credential;
     try {
       credential = JSON.parse(readFileSync(file, "utf8")) as Credential;
+      lastCredential = credential;
     } catch (err) {
       console.error(`mesh-tools: cannot read the broker credential at ${file}: ${err}`);
       process.exit(1);
@@ -54,7 +70,13 @@ async function connectBroker(): Promise<Broker> {
     // what the environment says.
     if (credential.node) process.env.MESH_NODE = credential.node;
     if (credential.module) process.env.MESH_MODULE = credential.module;
-    return connectAmqp(credential, { assumeExchanges: true });
+    // **The credential names the bus.** A module moved to the bus being built was handed a
+    // credential for it — `nats://…` with user, password and fingerprint beside the address — and
+    // nothing else in its environment changed (design 25; novox/hq design 28 task 5.2). The scheme
+    // is enough to know which bus to speak; a runtime that always dialled the old one would keep
+    // serving and answer nobody.
+    // One bus (novox/hq ADR 0131, design 28 task 5.5): the credential names it, and it is this.
+    return connectNats(credential);
   }
   const url = process.env.MESH_BROKER_URL;
   if (!url) {
@@ -63,7 +85,7 @@ async function connectBroker(): Promise<Broker> {
     );
     process.exit(1);
   }
-  return connectAmqp(url);
+  return connectNats({ url });
 }
 
 /**
@@ -83,7 +105,7 @@ async function connectBrokerPatiently(): Promise<Broker> {
     try {
       return await connectBroker();
     } catch (err) {
-      const fatal = fatalBrokerReason(err);
+      const fatal = fatalBrokerReasonFor(err);
       if (fatal !== null) {
         console.error(`mesh-tools: ${fatal} — waiting will not fix this; giving up`);
         throw err;
@@ -98,17 +120,68 @@ async function connectBrokerPatiently(): Promise<Broker> {
   }
 }
 
-async function serve(): Promise<void> {
+/**
-  const moduleEntrypoints = (process.env.MESH_TOOL_MODULES ?? "")
+ * What MESH_TOOL_MODULES names (novox/hq ADR 0175, to-be 38 WP1): `<module>=<entrypoint>` entries,
-    .split(",")
+ * comma-separated, several per module allowed — the node's runtime serving every assigned module's
-    .map((s) => s.trim())
+ * bundle. A bare path is the one-module form the per-module containers still set: an entrypoint of
-    .filter(Boolean);
+ * the credential's own module. Both may appear; the result is one list of modules.
+ */
+export function servedModulesFrom(spec: string, own: string | undefined): { serves: ServedModule[]; moduleEntrypoints: string[] } {
+  const serves = new Map<string, string[]>();
+  const moduleEntrypoints: string[] = [];
+  for (const raw of spec.split(",")) {
+    const entry = raw.trim();
+    if (!entry) continue;
+    const eq = entry.indexOf("=");
+    if (eq < 0) {
+      moduleEntrypoints.push(entry);
+      continue;
+    }
+    const module = entry.slice(0, eq).trim();
+    const path = entry.slice(eq + 1).trim();
+    if (!module || !path) {
+      throw new Error(`MESH_TOOL_MODULES: "${entry}" is neither <module>=<entrypoint> nor an entrypoint of this module`);
+    }
+    if (module === own) {
+      moduleEntrypoints.push(path);
+      continue;
+    }
+    serves.set(module, [...(serves.get(module) ?? []), path]);
+  }
+  return { serves: [...serves].map(([module, entrypoints]) => ({ module, entrypoints })), moduleEntrypoints };
+}
 
+/** The module that is the node's tool runtime (novox/hq ADR 0175, to-be 38 WP3): on its credential,
+ *  `serve` is also the console — MCP on the machine's loopback (design 34). */
+export const RUNTIME_MODULE = "node-tools";
+
+/** Where the console listens when the runtime is node-tools and nothing says otherwise: the port
+ *  the module's manifest declares `from: machine`. MESH_CONSOLE_LISTEN overrides it either way. */
+const CONSOLE_LISTEN = "127.0.0.1:4270";
+
+async function serve(): Promise<void> {
   const broker = await connectBrokerPatiently();
-  const stop = await runTools({ broker, moduleEntrypoints });
+  // Parsed after connecting: a bare entrypoint belongs to the module the credential names.
+  const { serves, moduleEntrypoints } = servedModulesFrom(process.env.MESH_TOOL_MODULES ?? "", lastCredential?.module);
+  // Each module's environment, composed by the mesh (ADR 0192): taken before any bundle is imported.
+  const envs = takeToolEnvs();
+  const stop = await runTools({ broker, serves, moduleEntrypoints, credential: lastCredential, envs });
+
+  // The console is this runtime's serving mode (ADR 0175 §6): as node-tools, or wherever the
+  // listen address is given, the same process answers MCP on loopback for whoever is on the
+  // machine. A module's own runtime in a container on the machine's network does not — two of
+  // them on one port would be the fault, and the console is one per machine.
+  const listen = process.env.MESH_CONSOLE_LISTEN ?? (lastCredential?.module === RUNTIME_MODULE ? CONSOLE_LISTEN : "");
+  let consoleUp: Listening | undefined;
+  if (listen) {
+    const who = `${lastCredential?.node ?? "?"}.${lastCredential?.module ?? RUNTIME_MODULE}`;
+    consoleUp = await serveMcpHttp(broker, who, listen);
+    console.log(`mesh console listening on http://${consoleUp.address}/mcp as ${who}`);
+  }
 
   const shutdown = async (): Promise<void> => {
     stop();
+    await consoleUp?.close();
     await broker.close();
     process.exit(0);
   };
@@ -166,12 +239,49 @@ async function runEntry(entrypoint: string): Promise<void> {
   await import(pathToFileURL(entrypoint).href);
 }
 
+/**
+ * Bring this module's state to the shape this version needs, and exit — the runtime's answer to the
+ * one word the mesh asks every module (novox/hq ADR 0135).
+ *
+ * The entrypoints come from `MESH_PREPARE`, which a module's own image sets beside the entrypoints it
+ * already lists there: the module knows which of its files prepares its state, and nothing else could.
+ * Each is imported in the order given, to completion, with no broker — preparation runs before the
+ * version that would use it, so there is nothing yet to talk to.
+ *
+ * **An empty list is a failure, not a no-op.** The mesh only asks this of a module whose manifest says
+ * it prepares something; a module that says so and names nothing has been built wrong, and exiting 0
+ * would let that version serve against a state nobody shaped.
+ */
+async function prepareState(): Promise<void> {
+  const named = (process.env.MESH_PREPARE ?? "")
+    .split(",")
+    .map((entry) => entry.trim())
+    .filter((entry) => entry !== "");
+  if (named.length === 0) {
+    console.error(
+      "mesh-tools prepare: this module was asked to prepare its state and its image names nothing " +
+        "to do it with — set MESH_PREPARE to the compiled entrypoint(s) that prepare it, the way " +
+        "MESH_TOOL_MODULES names the ones it serves",
+    );
+    process.exit(1);
+  }
+  for (const entrypoint of named) {
+    console.log(`[mesh-tools] preparing with ${entrypoint}`);
+    await runEntry(entrypoint);
+  }
+  console.log(`[mesh-tools] prepared: ${named.length} entrypoint(s) ran to completion`);
+}
+
 async function main(): Promise<void> {
   const [command, ...rest] = process.argv.slice(2);
   if (command === "run") {
     await runEntry(rest[0] ?? "");
     return;
   }
+  if (command === "prepare") {
+    await prepareState();
+    return;
+  }
   if (command === "invoke") {
     const [module, tool] = rest;
     if (!module || !tool) {
@@ -193,4 +303,7 @@ async function main(): Promise<void> {
   await serve();
 }
 
-void main();
+// Only when run, so a test can import the pieces.
+if (process.argv[1] && import.meta.url === new URL(`file://${process.argv[1]}`).href) {
+  void main();
+}

node-tools/src/mcp.ts

@@ -0,0 +1,258 @@
+/**
+ * The mesh's tools as an MCP server (novox/hq design 25 §7, design 34).
+ *
+ * **A thin adapter and nothing more.** Every tool an agent sees is one a module answered for and one
+ * this account may call; the schema is the module's own; the answer is the module's own. Nothing here
+ * decides anything, which is why it is short — an MCP surface that reshaped arguments or summarised
+ * answers would be a second definition of what a tool is, and the module's code is the first.
+ *
+ * Implemented against the protocol directly rather than through a library: the surface is three
+ * methods and one framing, and a dependency here would be a dependency on every machine.
+ *
+ * One handler, two transports. Over stdio for a program a person starts (`mesh mcp`), over HTTP on a
+ * machine's loopback for the console the mesh assigns there (`mesh serve`, http.ts). The handler does
+ * not know which asked.
+ */
+import type { Broker } from "@novox/mesh-sdk/messaging";
+
+import { callTool, seatsIn, toolKey, toolsOn, whyItFailed, type Listing, type Seats } from "./client.js";
+
+/** The protocol version this speaks. Stated, because a host that wants another should be told so
+ *  rather than discovering it through a shape it did not expect. */
+export const PROTOCOL = "2025-03-26";
+
+export interface Request {
+  jsonrpc: string;
+  id?: number | string | null;
+  method: string;
+  params?: Record<string, unknown>;
+}
+
+export interface Reply {
+  jsonrpc: "2.0";
+  id: Request["id"];
+  result?: unknown;
+  error?: { code: number; message: string };
+}
+
+/** How long a fetched tool list is kept before the modules are asked again. An agent asks on every
+ *  turn; the mesh changes on the order of minutes. */
+export const LISTING_KEPT_MS = 30_000;
+
+export interface Surface {
+  /** Answer one request; undefined for a notification, which expects none. */
+  handle(request: Request): Promise<Reply | undefined>;
+}
+
+/**
+ * The surface over one bus connection, as one account.
+ *
+ * The tool list is fetched when first asked and kept for a short while (design 34 §3): asking every
+ * module on every `tools/list` would fan out on every agent turn for something nobody changed, and
+ * never refreshing would hide a module assigned a moment ago.
+ */
+export function mcpSurface(bus: Broker, who: string): Surface {
+  let known: { listing: Listing; at: number } | undefined;
+
+  const answer = (id: Request["id"], result: unknown): Reply => ({ jsonrpc: "2.0", id, result });
+  const refuse = (id: Request["id"], code: number, message: string): Reply => ({
+    jsonrpc: "2.0",
+    id,
+    error: { code, message },
+  });
+
+  const listing = async (): Promise<Listing> => {
+    if (!known || Date.now() - known.at > LISTING_KEPT_MS) {
+      known = { listing: await toolsOn(bus), at: Date.now() };
+    }
+    return known.listing;
+  };
+  // The roles the last listing knew, so `<seat>.<verb>` resolves to the seat. Fetched once if a
+  // call arrives before any list did; a listing that failed leaves no roles, and the name is then
+  // a module's, which is the right fallback for a mesh whose control plane is away.
+  const roles = async (): Promise<Seats | undefined> => {
+    try {
+      return seatsIn(await listing());
+    } catch {
+      return undefined;
+    }
+  };
+
+  return {
+    async handle(request) {
+      // A notification has no id and expects no answer; `initialized` is the one every host sends.
+      const notification = request.id === undefined || request.id === null;
+
+      switch (request.method) {
+        case "initialize":
+          return answer(request.id, {
+            protocolVersion: PROTOCOL,
+            capabilities: { tools: {} },
+            serverInfo: { name: "mesh", version: "1" },
+            // Said in the handshake, because an agent that knows whose authority it is acting under
+            // can say so when a call is refused — and a refusal is the one thing here that is not
+            // the mesh's fault or the tool's.
+            instructions:
+              `These are the tools of a Novox mesh, reached as ${who}. Every call goes to the module ` +
+              `that serves it; what may be called was fixed when this account was issued, so a ` +
+              `refusal means the account, not the tool. The list is what the running modules ` +
+              `answered, plus every role's tools from the mesh's records — the mesh's own verbs ` +
+              `(mesh-controller.status, .push, .assign …) among them; a module that did not answer ` +
+              `is named in the list's _meta and can still be called by <module>.<tool>.`,
+          });
+
+        case "notifications/initialized":
+          return undefined;
+
+        case "ping":
+          return notification ? undefined : answer(request.id, {});
+
+        case "tools/list": {
+          let have: Listing;
+          try {
+            have = await listing();
+          } catch (e) {
+            return refuse(request.id, -32603, whyItFailed("mesh-catalog.catalog_modules", e));
+          }
+          return answer(request.id, {
+            tools: have.tools.map((t) => ({
+              name: `${t.module}.${t.name}`,
+              description: t.description ?? `${t.name}, served by ${t.module}`,
+              // The module's own schema, passed through — with `node`, the machine to ask when
+              // the module runs on several (novox/hq ADR 0159); a seat's verb takes none, the
+              // seat's scope decides. An empty object is a tool that takes nothing, which is a
+              // real answer and not a missing one.
+              inputSchema: t.seat && t.scope !== "node" ? asSchema(t.input)
+                : t.seat ? withNode(asSchema(t.input), "the machine whose seat answers; required, the seat is held once per machine", true)
+                : withNode(asSchema(t.input)),
+            })),
+            // Silence, named (design 34 §3): the modules the catalogue holds and nothing answered
+            // for. Not a tool, so not in `tools`; not dropped either.
+            _meta: { notAnswering: have.notAnswering },
+          });
+        }
+
+        case "tools/call": {
+          const given = String(request.params?.name ?? "");
+          const args = { ...((request.params?.arguments as Record<string, unknown> | undefined) ?? {}) };
+          // The machine, when the caller names one, travels in the subject and never reaches the
+          // module's arguments (novox/hq ADR 0159) — for a module's tool. A seat's verb takes no
+          // machine from the console (the seat's scope decides), so a `node` among its arguments
+          // is the verb's own, as `push` and `assign` take one, and is handed through untouched.
+          const have = await listing().catch(() => undefined);
+          const roles = have && seatsIn(have);
+          const bare = given.split("@", 1)[0];
+          const isSeatVerb = roles ? toolKey(bare, roles).startsWith("seat:") : false;
+          // A node-scoped seat's verb is asked of one machine (design 33 §4, ADR 0170): `node`
+          // names it and travels in the subject, as for a module's tool.
+          const nodeScoped = isSeatVerb && (have?.tools.some((t) => t.seat && t.scope === "node" &&
+            `${t.module}.${t.name}` === bare) ?? false);
+          const takesNode = !isSeatVerb || nodeScoped;
+          const node = takesNode && typeof args.node === "string" && args.node !== "" ? args.node : "";
+          if (takesNode) delete args.node;
+          if (nodeScoped && !node && !given.includes("@")) {
+            return refuse(request.id, -32602, `${given} is a machine's seat's verb: name the machine with \`node\``);
+          }
+          const name = node && !given.includes("@") ? `${given}@${node}` : given;
+          try {
+            const { result, node: answeredBy } = await callTool(bus, name, args, roles, have);
+            // Text, because that is what every host renders. The content is the module's answer
+            // as JSON, unshaped: an adapter that flattened it would be deciding what matters in
+            // somebody else's answer. Which machine answered follows it as its own line.
+            const content: { type: string; text: string }[] = [
+              { type: "text", text: JSON.stringify(result, null, 2) },
+            ];
+            if (answeredBy) content.push({ type: "text", text: `answered by ${answeredBy}` });
+            return answer(request.id, { content });
+          } catch (e) {
+            // **An error the agent can act on, not a stack.** isError rather than a protocol
+            // failure, because the call was well-formed and the mesh answered it — with a refusal,
+            // an absence or a fault, and the words say which.
+            return answer(request.id, {
+              content: [{ type: "text", text: whyItFailed(name, e) }],
+              isError: true,
+            });
+          }
+        }
+
+        default:
+          return notification ? undefined : refuse(request.id, -32601, `mesh's MCP surface has no ${request.method}`);
+      }
+    },
+  };
+}
+
+/**
+ * A module's declared input as a JSON schema an agent can read.
+ *
+ * The sdk keeps a tool's input opaque, and the catalogue's modules write it as a bare map of
+ * property to description — `{ module: { type, description } }` — which is the `properties` of a
+ * schema rather than a schema. Wrapped here when that is what arrived; passed through when a module
+ * already wrote a schema; an empty object when it declared nothing. The module's words are kept
+ * either way.
+ */
+export function asSchema(input: unknown): Record<string, unknown> {
+  if (!input || typeof input !== "object" || Array.isArray(input)) {
+    return { type: "object", properties: {} };
+  }
+  const given = input as Record<string, unknown>;
+  if (given.type === "object" || "properties" in given) return given;
+  if (Object.keys(given).length === 0) return { type: "object", properties: {} };
+  return { type: "object", properties: given };
+}
+
+/**
+ * Serve over stdio until stdin closes, which is how a host ends a session.
+ */
+export async function serveMcp(bus: Broker, who: string): Promise<void> {
+  const surface = mcpSurface(bus, who);
+  const say = (message: unknown) => {
+    process.stdout.write(`${JSON.stringify(message)}\n`);
+  };
+  for await (const line of lines()) {
+    let request: Request;
+    try {
+      request = JSON.parse(line) as Request;
+    } catch {
+      // Unparseable, and with no id there is nobody to tell. Skipped rather than answered, because a
+      // reply to a request that was never framed is noise on the same channel.
+      continue;
+    }
+    const reply = await surface.handle(request);
+    if (reply) say(reply);
+  }
+}
+
+/** stdin as newline-framed messages, which is what MCP over stdio is. */
+async function* lines(): AsyncGenerator<string> {
+  let buffered = "";
+  for await (const chunk of process.stdin) {
+    buffered += (chunk as Buffer).toString("utf8");
+    let at: number;
+    while ((at = buffered.indexOf("\n")) >= 0) {
+      const line = buffered.slice(0, at).trim();
+      buffered = buffered.slice(at + 1);
+      if (line !== "") yield line;
+    }
+  }
+  if (buffered.trim() !== "") yield buffered.trim();
+}
+
+/** Every module tool takes an optional `node`: the machine to ask when the module runs on several
+ *  (novox/hq ADR 0159). Added to the listing, stripped before the call, never seen by the module. */
+function withNode(schema: Record<string, unknown>, description?: string, required = false): Record<string, unknown> {
+  const properties = { ...((schema.properties as Record<string, unknown> | undefined) ?? {}) };
+  if (!("node" in properties)) {
+    properties.node = {
+      type: "string",
+      description: description ??
+        "the machine to ask, when this module runs on several; else whichever answers, and the answer says which",
+    };
+  }
+  const out: Record<string, unknown> = { ...schema, type: "object", properties };
+  if (required) {
+    const have = Array.isArray(schema.required) ? (schema.required as string[]) : [];
+    out.required = have.includes("node") ? have : [...have, "node"];
+  }
+  return out;
+}

node-tools/src/mesh.ts

@@ -0,0 +1,278 @@
+#!/usr/bin/env node
+/**
+ * `mesh` — the mesh's tools, for whoever is on a machine (novox/hq design 25 §7, design 34).
+ *
+ * Four verbs and nothing else. What tools are there, call one, serve the same two to an agent over
+ * stdio, and serve them on a machine's loopback as the console the mesh assigns. Deliberately thin:
+ * everything that could be a decision is one the mesh already made, and a client that grew opinions
+ * would be a second place the mesh's behaviour is defined.
+ *
+ *     mesh tools                        what the running modules answer
+ *     mesh call <module>.<tool> [json]  call one, arguments as JSON on the command line or on stdin
+ *     mesh mcp                          the same two, as an MCP server over stdio
+ *     mesh serve [--listen host:port]   the console: MCP over HTTP on this machine's loopback
+ *
+ * Who it speaks as, in order of preference:
+ *   MESH_BROKER_FILE     the module credential the mesh delivered — the console's (ADR 0152)
+ *   MESH_CREDENTIAL / --credential <file>   a person's, as `operator issue` printed it (design 25 §7)
+ *   MESH_CONSOLE / --console <url>          no credential: `tools` and `call` go through a console
+ *                                           already running on this machine, over loopback HTTP
+ */
+import { readFile } from "node:fs/promises";
+
+import type { Broker } from "@novox/mesh-sdk/messaging";
+
+import {
+  callTool,
+  connectAs,
+  connectAsTheConsole,
+  credentialFrom,
+  seatsIn,
+  toolsOn,
+  whyItFailed,
+  type Listing,
+} from "./client.js";
+import { serveMcpHttp } from "./http.js";
+import { serveMcp } from "./mcp.js";
+
+const usage = `mesh tools
+mesh call <module>.<tool> [json]
+mesh mcp
+mesh serve [--listen host:port]
+
+  --credential <file>   a person's credential, the JSON \`operator issue\` printed; default $MESH_CREDENTIAL
+  --console <url>       a console on this machine to ask through instead; default $MESH_CONSOLE
+  --listen <host:port>  where \`serve\` listens; loopback only; default $MESH_CONSOLE_LISTEN or 127.0.0.1:4270
+  MESH_BROKER_FILE      the module credential the mesh delivered, which \`serve\` runs on`;
+
+/** What the console listens on when nothing says otherwise. */
+const DEFAULT_LISTEN = "127.0.0.1:4270";
+
+async function main(argv: string[]): Promise<number> {
+  const args = [...argv];
+  let credentialPath = process.env.MESH_CREDENTIAL ?? "";
+  let consoleUrl = process.env.MESH_CONSOLE ?? "";
+  let listen = process.env.MESH_CONSOLE_LISTEN ?? DEFAULT_LISTEN;
+  for (let i = 0; i < args.length; i++) {
+    const take = () => {
+      const v = args[i + 1] ?? "";
+      args.splice(i, 2);
+      i--;
+      return v;
+    };
+    if (args[i] === "--credential") credentialPath = take();
+    else if (args[i] === "--console") consoleUrl = take();
+    else if (args[i] === "--listen") listen = take();
+  }
+  const verb = args.shift();
+  if (!verb || verb === "help" || verb === "--help") {
+    console.log(usage);
+    return verb ? 0 : 1;
+  }
+
+  // Through a console already on this machine: no credential to hold, which is the point of one.
+  if (consoleUrl && (verb === "tools" || verb === "call")) {
+    return verb === "tools" ? listingVia(consoleUrl) : callingVia(consoleUrl, args);
+  }
+
+  const { bus, who } = await connecting(credentialPath, verb);
+  try {
+    switch (verb) {
+      case "tools":
+        return await listing(bus, who);
+      case "call":
+        return await calling(bus, args);
+      case "mcp":
+        // Serves until stdin closes, which is how an MCP host ends a session.
+        await serveMcp(bus, who);
+        return 0;
+      case "serve": {
+        const up = await serveMcpHttp(bus, who, listen);
+        console.log(`mesh console listening on http://${up.address}/mcp as ${who}`);
+        await new Promise<void>((resolve) => {
+          process.once("SIGTERM", () => resolve());
+          process.once("SIGINT", () => resolve());
+        });
+        await up.close();
+        return 0;
+      }
+      default:
+        console.error(`mesh has no "${verb}".\n\n${usage}`);
+        return 1;
+    }
+  } finally {
+    await bus.close();
+  }
+}
+
+/**
+ * Who this process is on the bus. The module credential first: a console is started by the mesh with
+ * MESH_BROKER_FILE and nothing else, and must not fall back to a person's file lying around.
+ */
+async function connecting(credentialPath: string, verb: string): Promise<{ bus: Broker; who: string }> {
+  const delivered = process.env.MESH_BROKER_FILE;
+  if (delivered) {
+    return connectAsTheConsole(delivered);
+  }
+  if (!credentialPath) {
+    throw new Error(
+      verb === "serve"
+        ? "no credential: the console runs on MESH_BROKER_FILE, the module credential the mesh " +
+          "delivered; to run it by hand, pass --credential <file> with a person's credential"
+        : "no credential: set MESH_CREDENTIAL or pass --credential <file> (the JSON `operator issue` " +
+          "printed, saved verbatim), or --console <url> to ask through a console on this machine",
+    );
+  }
+  const held = await credentialFrom(credentialPath);
+  return { bus: await connectAs(held), who: held.person ?? held.user ?? "somebody" };
+}
+
+function printListing(have: Listing, who?: string): void {
+  if (have.tools.length === 0) {
+    console.log("no running module answered with any tool");
+  }
+  // **What the modules answered, not what this account may call.** The two differ and the
+  // difference is the point: an account seeing only its own tools cannot tell "not installed" from
+  // "not yours", and those need different people to fix them.
+  for (const t of have.tools) {
+    const name = `${t.module}.${t.name}`;
+    const line = t.description ? `${name.padEnd(36)} ${t.description}` : name;
+    console.log(t.seat ? `${line}  (a role's tool: answered by whoever holds the ${t.module} seat)` : line);
+  }
+  if (have.notAnswering.length > 0) {
+    console.log(
+      `\nheld by the mesh and not answering: ${have.notAnswering.join(", ")} — not assigned, not up, ` +
+        "or built before the runtime answered `tools`; each can still be called by name",
+    );
+  }
+  if (who) {
+    console.log(`\nasked as ${who}; what ${who} may call was fixed when the account was issued.`);
+  }
+}
+
+async function listing(bus: Broker, who?: string): Promise<number> {
+  let have: Listing;
+  try {
+    have = await toolsOn(bus);
+  } catch (e) {
+    console.error(whyItFailed("mesh-catalog.catalog_modules", e));
+    return 1;
+  }
+  printListing(have, who);
+  return 0;
+}
+
+async function calling(bus: Broker, args: string[]): Promise<number> {
+  const key = args.shift();
+  if (!key) {
+    console.error("mesh call <module>.<tool> [json]");
+    return 1;
+  }
+  const parsed = await argumentsFrom(args);
+  if (parsed === undefined) return 1;
+  try {
+    // `<seat>.<verb>` reaches the role when the mesh lists that verb for the seat; `seat:` says so
+    // outright and asks nothing first.
+    const have = key.startsWith("seat:") ? undefined : await toolsOn(bus).catch(() => undefined);
+    const { result, node } = await callTool(bus, key, parsed, have && seatsIn(have), have);
+    console.log(JSON.stringify(result, null, 2));
+    if (node) console.error(`answered by ${node}`);
+    return 0;
+  } catch (e) {
+    console.error(whyItFailed(key, e));
+    return 1;
+  }
+}
+
+/** The console's answer to one MCP request, over loopback HTTP. */
+async function viaConsole(consoleUrl: string, method: string, params?: unknown): Promise<any> {
+  const endpoint = consoleUrl.endsWith("/mcp") ? consoleUrl : `${consoleUrl.replace(/\/$/, "")}/mcp`;
+  const res = await fetch(endpoint, {
+    method: "POST",
+    headers: { "content-type": "application/json", accept: "application/json" },
+    body: JSON.stringify({ jsonrpc: "2.0", id: 1, method, params }),
+  });
+  if (!res.ok) {
+    throw new Error(`the console at ${endpoint} answered ${res.status}`);
+  }
+  const reply = (await res.json()) as { result?: any; error?: { message: string } };
+  if (reply.error) throw new Error(reply.error.message);
+  return reply.result;
+}
+
+async function listingVia(consoleUrl: string): Promise<number> {
+  try {
+    const result = await viaConsole(consoleUrl, "tools/list");
+    const have: Listing = {
+      tools: (result.tools ?? []).map((t: { name: string; description?: string; inputSchema?: unknown }) => {
+        const at = t.name.indexOf(".");
+        return { module: t.name.slice(0, at), name: t.name.slice(at + 1), description: t.description, input: t.inputSchema };
+      }),
+      notAnswering: result._meta?.notAnswering ?? [],
+    };
+    printListing(have);
+    return 0;
+  } catch (e) {
+    console.error(e instanceof Error ? e.message : String(e));
+    return 1;
+  }
+}
+
+async function callingVia(consoleUrl: string, args: string[]): Promise<number> {
+  const key = args.shift();
+  if (!key) {
+    console.error("mesh call <module>.<tool> [json]");
+    return 1;
+  }
+  const parsed = await argumentsFrom(args);
+  if (parsed === undefined) return 1;
+  try {
+    const result = await viaConsole(consoleUrl, "tools/call", { name: key, arguments: parsed });
+    const text = result?.content?.[0]?.text ?? JSON.stringify(result);
+    if (result?.isError) {
+      console.error(text);
+      return 1;
+    }
+    console.log(text);
+    return 0;
+  } catch (e) {
+    console.error(e instanceof Error ? e.message : String(e));
+    return 1;
+  }
+}
+
+/** A call's arguments: JSON on the command line, else on stdin, else nothing. Undefined when what
+ *  was given is not JSON, after saying so. */
+async function argumentsFrom(args: string[]): Promise<unknown> {
+  const raw = args.length > 0 ? args.join(" ") : await maybeStdin();
+  if (raw.trim() === "") return {};
+  try {
+    return JSON.parse(raw);
+  } catch (e) {
+    console.error(`the arguments are not JSON: ${(e as Error).message}`);
+    return undefined;
+  }
+}
+
+/** Arguments on stdin, for a call whose JSON is too long or too quoted to type. Empty when stdin is a
+ *  terminal, so `mesh call x.y` with no arguments does not hang waiting for something nobody is
+ *  typing. */
+async function maybeStdin(): Promise<string> {
+  if (process.stdin.isTTY) return "";
+  const chunks: Buffer[] = [];
+  for await (const chunk of process.stdin) chunks.push(chunk as Buffer);
+  return Buffer.concat(chunks).toString("utf8");
+}
+
+// Only when run, so a test can import the pieces.
+if (process.argv[1] && import.meta.url === new URL(`file://${process.argv[1]}`).href) {
+  main(process.argv.slice(2))
+    .then((code) => process.exit(code))
+    .catch((e) => {
+      console.error(e instanceof Error ? e.message : String(e));
+      process.exit(1);
+    });
+}
+
+export { main, usage };
+export const _readFile = readFile;

node-tools/src/runtime.ts

@@ -0,0 +1,384 @@
+// The tool runtime — the per-node process that makes the mesh's tools actually serve (novox/hq
+// ADR 0175). It binds the mesh broker, loads the served modules' tool bundles (each of which calls
+// registerModuleTools as it imports), and serves every module's tools on that module's subjects and
+// every held seat's verbs on the seat's. Everything hard — dispatch, collection, duplicate-name
+// safety — is the sdk's; this is the wrapper.
+//
+// One runtime, many modules. It was written for one module per process and ran that way in a
+// container per module; it now serves a list, as the one process per node the host supervises,
+// and the per-module shape is the list with one entry. A bundle that fails to import is named —
+// in the log and in what `tools` answers for it — and the others serve.
+
+import { pathToFileURL } from "node:url";
+import { resolve } from "node:path";
+import { useBroker } from "@novox/mesh-sdk/messaging";
+import { collectTools, toolKey, type ToolDefinition } from "@novox/mesh-sdk/tools";
+import type { Broker } from "@novox/mesh-sdk/messaging";
+import { atWork, seatToolSubject, type Credential, type RuntimeBroker } from "./broker-nats.js";
+import { launch, launches } from "./launch.js";
+import { announce, endpointsOf, type ServedSeatVerb } from "./announce.js";
+
+/**
+ * The one verb every module's runtime answers for it (novox/hq ADR 0152, design 34 §3): the
+ * module's tool names, descriptions and argument schemas, from the code that answers them and
+ * from nowhere else. Discovery asks the module, because a copy kept anywhere else drifts.
+ */
+export const TOOLS_VERB = "tools";
+
+/** What `tools` answers for one module. */
+export interface ToolsAnswer {
+  module: string;
+  tools: {
+    name: string;
+    description: string;
+    input: Readonly<Record<string, unknown>>;
+    /** Where this tool is answered, as the mesh issued it (ADR 0160): the module's plain subject
+     *  first when there is one, then this machine's. A caller composes nothing. */
+    subjects?: string[];
+  }[];
+  /** Why this module serves nothing here, when its bundle failed to load (ADR 0175): said where
+   *  discovery looks, so a module that is silent and one that is broken are told apart. */
+  failed?: string;
+}
+
+/** One module this runtime serves: its name and its compiled tool entrypoints. */
+export interface ServedModule {
+  module: string;
+  /** Absolute paths to the module's compiled tool entrypoints (e.g. .../umami/tools/index.js). */
+  entrypoints: string[];
+}
+
+export interface RuntimeOptions {
+  /** The mesh broker to serve over. */
+  broker: Broker;
+  /** The modules to serve, each with its entrypoints. */
+  serves?: ServedModule[];
+  /** The credential's own module's entrypoints — the one-module form, which the per-module
+   *  containers still use; the same as naming the credential's module in `serves`. */
+  moduleEntrypoints?: string[];
+  /** The credential the mesh delivered, for what it says about the seats this module claims
+   *  (novox/hq ADR 0159). Absent for a runtime started by hand, which then serves no seat its
+   *  memberships do not name. */
+  credential?: Credential;
+  /** What each served module's bundles are given (novox/hq ADR 0192): module → words, composed by
+   *  the mesh per machine. A module absent here is given the runtime's own words and nothing more. */
+  envs?: ReadonlyMap<string, Readonly<Record<string, string>>>;
+}
+
+/** The variable the mesh composes every served module's environment into, as JSON (ADR 0192). Read
+ *  once at start and removed from the process's environment, so no bundle finds another's there. */
+export const TOOL_ENV = "MESH_TOOL_ENV";
+
+/** Read and remove the composed environments from an environment (the process's, by default). */
+export function takeToolEnvs(env: NodeJS.ProcessEnv = process.env): Map<string, Record<string, string>> {
+  const raw = env[TOOL_ENV];
+  delete env[TOOL_ENV];
+  const out = new Map<string, Record<string, string>>();
+  if (!raw) return out;
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(raw);
+  } catch {
+    throw new Error(`${TOOL_ENV} is not JSON; the mesh composes it as {"<module>": {"<word>": "<value>"}}`);
+  }
+  if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) {
+    throw new Error(`${TOOL_ENV} is not an object of modules`);
+  }
+  for (const [module, words] of Object.entries(parsed as Record<string, unknown>)) {
+    if (!words || typeof words !== "object" || Array.isArray(words)) {
+      throw new Error(`${TOOL_ENV}: ${module}'s environment is not an object of words`);
+    }
+    const own: Record<string, string> = {};
+    for (const [k, v] of Object.entries(words as Record<string, unknown>)) own[k] = String(v);
+    out.set(module, own);
+  }
+  return out;
+}
+
+/** Two environment words the mesh sets for the node's runtime and every tool reads from its
+ *  environment: whose machine this is (novox/hq to-be 37 §3, ADR 0175). */
+export const OPERATOR_ACCOUNT = "MESH_OPERATOR_ACCOUNT";
+export const OPERATOR_HOME = "MESH_OPERATOR_HOME";
+
+/** Load the modules, bind the broker, and serve. Returns a stop function that unhooks serving. */
+export async function runTools(opts: RuntimeOptions): Promise<() => void> {
+  useBroker(() => opts.broker);
+  const runtime = opts.broker as RuntimeBroker;
+  // Whose runtime this is: the credential's module, or the connection's own when a runtime is
+  // started by hand without one — the broker was told its module when it connected.
+  const self = opts.credential?.module ?? (typeof runtime.module === "string" ? runtime.module : undefined);
+
+  // What to serve: the list, with the one-module form folded in as the credential's own entry.
+  const served = new Map<string, string[]>();
+  for (const s of opts.serves ?? []) {
+    served.set(s.module, [...(served.get(s.module) ?? []), ...s.entrypoints]);
+  }
+  const ownEntrypoints = opts.moduleEntrypoints ?? [];
+  if (opts.moduleEntrypoints?.length) {
+    if (!self) {
+      throw new Error(
+        "entrypoints were given with no module to serve them as: name the module (MESH_TOOL_MODULES " +
+          "as <module>=<entrypoint>) or connect on a credential that names one",
+      );
+    }
+    served.set(self, [...(served.get(self) ?? []), ...opts.moduleEntrypoints]);
+  }
+
+  // The operator's machine, said once so a tool's behaviour under it can be read back from the
+  // log. Tools read the two words from their own environment, which is this process's.
+  const account = process.env[OPERATOR_ACCOUNT];
+  if (account) {
+    console.log(`[mesh-tools] the operator's account here is ${account}` +
+      (process.env[OPERATOR_HOME] ? ` (home ${process.env[OPERATOR_HOME]})` : ""));
+  }
+
+  // Follow every served module's membership before loading anything, so what each is issued is
+  // known when its tools are bound. A module's own runtime already follows its own.
+  if (typeof runtime.follow === "function") {
+    for (const module of served.keys()) await runtime.follow(module);
+  }
+
+  // What each module's bundles are given: the runtime's own words, and over them the module's own.
+  const envs = opts.envs ?? new Map<string, Record<string, string>>();
+  const envFor = (module: string): NodeJS.ProcessEnv => ({ ...process.env, ...(envs.get(module) ?? {}) });
+
+  // Every bundle this runtime serves is launched as a process and spoken to over MCP on stdio (ADR
+  // 0188, ADR 0193): given the runtime's words and its module's own, and told the module it serves
+  // it as. The runtime knows no language; an entrypoint that is not executable was not built to be
+  // served, and is refused by name. A bundle that fails to start is named, and the others serve
+  // (ADR 0175: one faulty bundle must not take the node's tools down).
+  //
+  // The one-module form — the credential's own module's entrypoints, which the per-module containers
+  // still use for their event handlers and provisioners until they move (to-be 38 WP4c) — is imported
+  // into this process as before: one module, one SDK, its container's own environment.
+  // The machine this runtime serves, which an event a launched tool emits is stamped with.
+  const node = opts.credential?.node ?? (typeof (runtime as unknown as { node?: unknown }).node === "string" ? (runtime as unknown as { node: string }).node : undefined);
+  const failed = new Map<string, string>();
+  const launched: { module: string; owner: string; tools: ToolDefinition[] }[] = [];
+  const children: Array<() => void> = [];
+  for (const [module, entrypoints] of served) {
+    const imported = module === self && ownEntrypoints.length > 0;
+    for (const entry of entrypoints) {
+      const path = resolve(entry);
+      try {
+        if (imported) {
+          await import(pathToFileURL(path).href);
+          continue;
+        }
+        if (!launches(path)) {
+          throw new Error(`${path} is not executable; a bundle the runtime serves is started, never imported, and its build makes it executable (novox/hq ADR 0193)`);
+        }
+        const child = await launch(module, path, {
+          ...envFor(module), MESH_SERVED_MODULE: module, MESH_MODULE: module,
+          ...(node ? { MESH_NODE: node } : {}),
+        });
+        children.push(child.stop);
+        for (const r of child.registrations) launched.push({ ...r, owner: module });
+      } catch (err) {
+        const why = err instanceof Error ? err.message : String(err);
+        failed.set(module, why);
+        console.log(`[mesh-tools] ${module}'s bundle ${entry} failed to load: ${why}; its tools are not served here`);
+      }
+    }
+  }
+
+  // A registration under a served module's name is that module's tools, served on its subjects.
+  // One under a seat's name is the module's implementation of that seat's verbs (ADR 0159, 0160):
+  // served on the seat's subjects by serveClaimedSeats where some served module claims the seat,
+  // never as a module's tools and never listed among them. A module named like its seat (the
+  // catalogue is the mesh-catalog seat) registers once and is both. Anything else is said and left
+  // out rather than fatal — on 2026-10-01 the credential of a module that had just learned to
+  // implement a seat did not yet name the claim, and the whole runtime restarted for it.
+  const claimed = seatsClaimed(served.keys(), self, opts.credential, runtime);
+  const registrations = [
+    ...collectTools().map((r) => ({ ...r, owner: self ?? r.module })),
+    ...launched,
+  ];
+  const ownRegistrations = registrations.filter(({ module, owner: by }) => {
+    if (served.has(module)) return true;
+    if (claimed.has(module)) return false;
+    console.log(`[mesh-tools] ${by} registers tools under "${module}", which is neither a module served here nor a seat one of them claims; not served until the mesh issues the claim`);
+    return false;
+  });
+  const stops: Array<() => void> = [...children];
+  const stop = (): void => stops.splice(0).forEach((s) => s());
+
+  // Refused before anything is bound if a module named a tool of its own `tools`: one name
+  // answering two things is the fault nobody can diagnose afterwards, and the runtime is the only
+  // place that sees both. Likewise two tools of one module under one name.
+  for (const { module, tools: own } of ownRegistrations) {
+    if (own.some((t) => t.name === TOOLS_VERB)) {
+      throw new Error(
+        `${module} names a tool "${TOOLS_VERB}", which is the verb the runtime answers for every ` +
+          "module with what it serves (novox/hq ADR 0152) — refused, rename it",
+      );
+    }
+    const seen = new Set<string>();
+    for (const t of own) {
+      if (seen.has(t.name)) throw new Error(`${module} exposes two tools named ${t.name} — refused`);
+      seen.add(t.name);
+    }
+  }
+
+  // Each tool on its own key, namespaced by its module (ADR 0047); where that key is answered is
+  // the broker's to know from the module's membership (ADR 0160). A tool runs attributed to its
+  // module, so what it emits lands on the module's subject and not the runtime's.
+  const names: string[] = [];
+  for (const { module, tools: own } of ownRegistrations) {
+    for (const t of own) {
+      names.push(toolKey(module, t.name));
+      stops.push(await opts.broker.handle(toolKey(module, t.name), (args: Record<string, unknown> | undefined) =>
+        atWork.run({ module }, () => t.run(args ?? {}))));
+    }
+  }
+
+  // And, for every served module, the verb that says what it serves — nothing, and why, for a
+  // module whose bundle failed. A module that registered nothing and did not fail is a pure-events
+  // module (the audit logger), whose scoped account may not declare the serve queue; it is left
+  // silent as it always was.
+  const byModule = new Map<string, ToolDefinition[]>();
+  for (const { module, tools: own } of ownRegistrations) {
+    byModule.set(module, [...(byModule.get(module) ?? []), ...own]);
+  }
+  for (const module of served.keys()) {
+    const own = byModule.get(module) ?? [];
+    const why = failed.get(module);
+    if (own.length === 0 && !why) continue;
+    const subjectsOf = (tool: string): string[] | undefined => {
+      const m = typeof runtime.membership === "function" ? runtime.membership(module) : undefined;
+      if (!m) return undefined;
+      const plain = m.serves.filter((s) => s.queue).map((s) => s.subject.replace("{tool}", tool));
+      const mine = m.serves.filter((s) => !s.queue).map((s) => s.subject.replace("{tool}", tool));
+      return [...plain, ...mine];
+    };
+    stops.push(await opts.broker.handle(toolKey(module, TOOLS_VERB), async (): Promise<ToolsAnswer> => ({
+      module,
+      tools: own.map((t) => ({ name: t.name, description: t.description, input: t.input, subjects: subjectsOf(t.name) })),
+      ...(why ? { failed: why } : {}),
+    })));
+  }
+
+  console.log(`[mesh-tools] serving ${names.length} tool(s) for ${served.size} module(s): ${names.join(", ") || "(none)"}` +
+    (failed.size ? `; not serving ${[...failed.keys()].join(", ")}, whose bundle(s) failed to load` : ""));
+  const seats = await serveClaimedSeats(runtime, [...served.keys()], self, opts.credential, registrations);
+  stops.push(seats.stop);
+  // **What it serves, it announces** (novox/hq ADR 0197), asked at the moment of the request.
+  if (typeof runtime.raw === "function") {
+    stops.push(announce(runtime, {
+      name: self ?? "runtime", id: runtime.node ?? self ?? "runtime",
+      description: `the tool runtime of ${self ?? "a module"}${runtime.node ? ` on ${runtime.node}` : ""}`,
+      metadata: runtime.node ? { node: runtime.node } : {},
+    }, () => endpointsOf(runtime, ownRegistrations, seats.serving())));
+  }
+  return () => stop();
+}
+
+/** The seats some served module claims: from the credential for its own module, and from every
+ *  served module's membership (ADR 0160) — the node's runtime holds no claims of its own. */
+function seatsClaimed(
+  modules: Iterable<string>,
+  self: string | undefined,
+  credential: Credential | undefined,
+  runtime: RuntimeBroker,
+): Set<string> {
+  const out = new Set<string>();
+  for (const c of credential?.claims ?? []) if (credential?.module === self) out.add(c.seat);
+  for (const module of modules) {
+    const m = typeof runtime.membership === "function" ? runtime.membership(module) : undefined;
+    for (const s of m?.seats ?? []) out.add(s.seat);
+  }
+  return out;
+}
+
+/** One seat's verb, where its callers ask, and which served module holds the seat. */
+interface SeatVerb {
+  seat: string;
+  verb: string;
+  subject: string;
+  holder: string;
+}
+
+/**
+ * Holding a seat means serving its tools (design 33 §3, novox/hq ADR 0159). What a served module
+ * claims and promises comes from its membership (ADR 0160) — and, for a module's own runtime, from
+ * its credential, which named the claims before memberships did. Each verb is served on the seat's
+ * own subject by the tool of the same name registered under the seat's name. Whether this instance
+ * *holds* the seat is the bus's to decide: only the holder's account may subscribe the seat's
+ * subjects, so a claimant that does not hold it here is refused the subscription and serves nothing
+ * — never a failure of its own tools.
+ */
+async function serveClaimedSeats(
+  broker: RuntimeBroker,
+  served: string[],
+  self: string | undefined,
+  credential: Credential | undefined,
+  registrations: { module: string; owner: string; tools: ToolDefinition[] }[],
+): Promise<{ stop: () => void; serving: () => ServedSeatVerb[] }> {
+  if (typeof broker.handleSubject !== "function") return { stop: () => {}, serving: () => [] };
+  // A seat's verbs are the role's, not the software's (ADR 0159): implemented under the seat's
+  // name — `registerModuleTools("mesh-store", …)` — and never confused with the module's own tools.
+  const implementations = new Map<string, Map<string, (args: Record<string, unknown>) => Promise<unknown>>>();
+  const definitions = new Map<string, Map<string, ToolDefinition>>();
+  for (const { module, tools } of registrations) {
+    const defs = definitions.get(module) ?? new Map<string, ToolDefinition>();
+    for (const t of tools) defs.set(t.name, t);
+    definitions.set(module, defs);
+  }
+  for (const { module, owner, tools } of registrations) {
+    const verbs = implementations.get(module) ?? new Map<string, (args: Record<string, unknown>) => Promise<unknown>>();
+    for (const t of tools) verbs.set(t.name, (args) => atWork.run({ module: owner }, () => t.run(args)));
+    implementations.set(module, verbs);
+  }
+
+  /** Every verb of every seat a served module claims, where the mesh issued it. */
+  const wanted = (): SeatVerb[] => {
+    const out: SeatVerb[] = [];
+    const have = new Set<string>();
+    const add = (v: SeatVerb): void => {
+      if (have.has(v.subject)) return;
+      have.add(v.subject);
+      out.push(v);
+    };
+    for (const module of served) {
+      const m = typeof broker.membership === "function" ? broker.membership(module) : undefined;
+      for (const s of m?.seats ?? []) add({ seat: s.seat, verb: s.verb, subject: s.subject, holder: module });
+      // The credential's claims, for the module's own runtime, ONLY until the mesh issues a
+      // membership (novox/hq issue 218). The credential names what the module claims; the membership
+      // names what it holds on this machine. A seat held once for the mesh is claimed by every
+      // machine running the module and held by one, so once a membership exists it decides: a claim
+      // it leaves out is not held here, and serving it anyway announced the seat from a machine the
+      // bus then refused it on.
+      if (module !== self || m) continue;
+      for (const claim of credential?.claims ?? []) {
+        for (const verb of claim.serves ?? []) {
+          const subject = seatToolSubject(claim.seat, verb, claim.scope, credential?.node);
+          add({ seat: claim.seat, verb, subject, holder: module });
+        }
+      }
+    }
+    return out;
+  };
+
+  let stops: (() => void)[] = [];
+  let servingNow: ServedSeatVerb[] = [];
+  const serve = async (): Promise<void> => {
+    stops.forEach((s) => s());
+    stops = [];
+    servingNow = [];
+    for (const v of wanted()) {
+      const run = implementations.get(v.seat)?.get(v.verb);
+      const tool = definitions.get(v.seat)?.get(v.verb);
+      if (!run) {
+        console.log(`[mesh-tools] ${v.holder} claims ${v.seat} and implements no ${v.verb}, which that seat promises; not served`);
+        continue;
+      }
+      stops.push(await broker.handleSubject(v.subject, run));
+      if (tool) servingNow.push({ ...v, tool });
+      console.log(`[mesh-tools] serving ${v.seat}'s ${v.verb} on ${v.subject}, admitted where ${v.holder} holds the seat`);
+    }
+  };
+  await serve();
+  // A membership issued to any served module may add, move or withdraw a seat's verbs.
+  if (typeof broker.onMembership === "function") broker.onMembership(() => void serve());
+  return { stop: () => stops.forEach((s) => s()), serving: () => servingNow };
+}

node-tools/test/announce.test.ts

@@ -0,0 +1,69 @@
+/**
+ * What a runtime serves, it announces (novox/hq ADR 0197): the TypeScript runtime the per-module
+ * containers still run answers the NATS services protocol's discovery in the same shape as the Go
+ * tool runtime — its module's tools on every subject issued, and the seat verbs it serves.
+ *
+ *   MESH_TEST_NATS=nats://127.0.0.1:14232 node --test --experimental-strip-types test/announce.test.ts
+ */
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { fileURLToPath } from "node:url";
+import { connect, StringCodec } from "nats";
+
+import { resetTools } from "@novox/mesh-sdk/tools";
+
+import { connectNats, membershipSubject } from "../dist/broker-nats.js";
+import { runTools } from "../dist/runtime.js";
+
+const url = process.env.MESH_TEST_NATS;
+const fixture = (name: string) => fileURLToPath(new URL(`./fixtures/${name}`, import.meta.url));
+const sc = StringCodec();
+
+test("the runtime answers $SRV.INFO with what it serves, in the services protocol's format", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const nc = await connect({ servers: url });
+  const jsm = await nc.jetstreamManager();
+  try {
+    await jsm.streams.delete("ASSIGNMENTS");
+  } catch {
+    // none yet
+  }
+  await jsm.streams.add({ name: "ASSIGNMENTS", subjects: ["mesh.assignment.>"], max_msgs_per_subject: 1, allow_direct: true } as never);
+  await nc.jetstream().publish(membershipSubject("anchor", "shop"), sc.encode(JSON.stringify({
+    node: "anchor", module: "shop",
+    serves: [{ subject: "mesh.mod.shop.tool.{tool}.anchor" }, { subject: "mesh.mod.shop.tool.{tool}", queue: "serve.shop" }],
+    emits: "mesh.mod.shop.event.{event}", tools: "mesh.mod.shop.tool.tools",
+  })));
+  const shop = await connectNats({ url, node: "anchor", module: "shop" });
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: shop, moduleEntrypoints: [fixture("shop-tools.mjs")] });
+    const msg = await nc.request("$SRV.INFO.shop.anchor", sc.encode(""), { timeout: 2000 });
+    const info = JSON.parse(sc.decode(msg.data)) as {
+      type: string; name: string; id: string; version: string;
+      endpoints: { name: string; subject: string; queue_group: string; metadata: Record<string, string> }[];
+    };
+    assert.equal(info.type, "io.nats.micro.v1.info_response");
+    assert.equal(info.name, "shop");
+    assert.equal(info.id, "anchor");
+    assert.ok(info.version);
+    const price = info.endpoints.filter((e) => e.metadata.tool === "price").map((e) => `${e.subject}|${e.queue_group}`).sort();
+    assert.deepEqual(price, ["mesh.mod.shop.tool.price.anchor|", "mesh.mod.shop.tool.price|serve.shop"]);
+    const one = info.endpoints.find((e) => e.metadata.tool === "price")!;
+    assert.equal(one.metadata.kind, "tool");
+    assert.equal(one.metadata.module, "shop");
+    assert.equal(one.metadata.node, "anchor");
+    assert.equal(one.metadata.interchangeable, "true");
+    assert.ok(JSON.parse(one.metadata.schema).type === "object");
+    // Ping answers with the same identity; another service's request is not answered.
+    const ping = JSON.parse(sc.decode((await nc.request("$SRV.PING", sc.encode(""), { timeout: 2000 })).data));
+    assert.equal(ping.type, "io.nats.micro.v1.ping_response");
+    await assert.rejects(nc.request("$SRV.INFO.somebody-else", sc.encode(""), { timeout: 300 }));
+  } finally {
+    stop();
+    await shop.close();
+    await nc.close();
+    resetTools();
+  }
+});

node-tools/test/client.test.ts

@@ -0,0 +1,188 @@
+/**
+ * A person's client, against a real bus.
+ *
+ * What is worth checking is not that a request/reply works — the runtime's own tests cover that — but
+ * that the two surfaces are the same thing. An agent and a person must see the same tools and get the
+ * same answers, or the MCP surface becomes a second definition of what a tool is.
+ *
+ *   docker run -d --rm --name t -p 14232:4222 nats:2.10-alpine -js
+ *   MESH_TEST_NATS=nats://127.0.0.1:14232 node --test --experimental-strip-types test/client.test.ts
+ */
+import assert from "node:assert/strict";
+import { test } from "node:test";
+
+// The built output, not the source: the client imports its siblings as `.js`, which is what ships and
+// what every other file here does, and cannot be loaded as TypeScript directly. `pretest` builds.
+import { connectNats } from "../dist/broker-nats.js";
+import { callTool, seatsIn, toolKey, toolsOn, whyItFailed } from "../dist/client.js";
+
+const url = process.env.MESH_TEST_NATS;
+
+/** A mesh as discovery sees it (design 34 §3): the catalogue holding three modules, two of them up
+ *  and answering `tools`, one held and not running. Two connections, because a person and a module
+ *  are different users even in a test. */
+async function aMeshWithTools() {
+  const catalogue = await connectNats({ url: url!, module: "mesh-catalog" });
+  const shop = await connectNats({ url: url!, module: "shop" });
+  await catalogue.handle("catalog_modules", async () => ({
+    modules: [{ module: "shop" }, { module: "mesh-catalog" }, { module: "ghost" }],
+  }));
+  await catalogue.handle("tools", async () => ({
+    module: "mesh-catalog",
+    tools: [{ name: "catalog_modules", description: "what modules the mesh has", input: {} }],
+  }));
+  await shop.handle("tools", async () => ({
+    module: "shop",
+    tools: [{ name: "price", description: "what something costs", input: { type: "object" } }],
+  }));
+  await shop.handle("price", async (body: { of?: string }) => ({ of: body.of ?? "nothing", cost: 12 }));
+  // And the mesh's own records, served by the holder of the mesh-controller seat (ADR 0154): one
+  // role's tool, and the verb that lists every role's.
+  const controller = await connectNats({ url: url!, module: "mesh-controller" });
+  await controller.handle("seat:mesh-controller.tools", async () => ({
+    seats: [
+      { seat: "mesh-controller", scope: "mesh", tools: [{ name: "status", description: "what is wrong", input: {} }] },
+      { seat: "node-dns-resolver", scope: "node", tools: [{ name: "lookup", description: "one machine's", input: {} }] },
+    ],
+  }));
+  await controller.handle("seat:mesh-controller.status", async () => ({ output: "all quiet", ok: true }));
+  return {
+    async close() {
+      await catalogue.close();
+      await shop.close();
+      await controller.close();
+    },
+  };
+}
+
+test("a person sees what the running modules answer, sorted, and who did not answer", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const mesh = await aMeshWithTools();
+  const person = await connectNats({ url, module: "person.ada" });
+  try {
+    const began = Date.now();
+    const have = await toolsOn(person);
+    assert.deepEqual(
+      have.tools.map((x) => `${x.module}.${x.name}`),
+      ["mesh-catalog.catalog_modules", "mesh-controller.status", "node-dns-resolver.lookup", "shop.price"],
+      "the list is what the modules answered plus every role's tools, in a stable order",
+    );
+    // A role's tool is marked as one; a node-scoped seat's carries its scope, so a caller names
+    // the machine and the verb resolves as the seat's (design 33 §4, ADR 0170).
+    assert.ok(have.tools.find((x) => x.module === "mesh-controller")!.seat);
+    const lookup = have.tools.find((x) => x.module === "node-dns-resolver")!;
+    assert.ok(lookup.seat && lookup.scope === "node");
+    assert.equal(toolKey("node-dns-resolver.lookup", seatsIn(have)), "seat:node-dns-resolver.lookup");
+    // Silence is named, never dropped: a module the catalogue holds and nothing answered for.
+    assert.deepEqual(have.notAnswering, ["ghost"]);
+    // And at once: a module that is not running costs nothing, or the list is unusable.
+    assert.ok(Date.now() - began < 5_000, "an absent module waited out the timeout");
+  } finally {
+    await person.close();
+    await mesh.close();
+  }
+});
+
+test("a person calls a tool and gets the module's own answer, unshaped", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const mesh = await aMeshWithTools();
+  const person = await connectNats({ url, module: "person.ada" });
+  try {
+    const answer = await callTool(person, "shop.price", { of: "a hat" });
+    assert.deepEqual(answer.result, { of: "a hat", cost: 12 });
+  } finally {
+    await person.close();
+    await mesh.close();
+  }
+});
+
+test("a tool nobody serves says so at once, and says what to do about it", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const person = await connectNats({ url: url!, module: "person.ada" });
+  try {
+    const began = Date.now();
+    await assert.rejects(() => callTool(person, "ghost.missing", {}));
+    // At once, not after the whole wait: "that module is down" and "that tool is slow" need
+    // different things done, and a timeout cannot tell them apart.
+    assert.ok(Date.now() - began < 5_000, "a tool nobody serves waited out the timeout");
+  } finally {
+    await person.close();
+  }
+});
+
+test("a name that is not <module>.<tool> is refused before anything is sent", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const person = await connectNats({ url: url!, module: "person.ada" });
+  try {
+    await assert.rejects(() => callTool(person, "price", {}), /does not name a tool/);
+  } finally {
+    await person.close();
+  }
+});
+
+test("each way a call fails says what to do about it", () => {
+  // The three answers a person actually gets. Without this they are one timeout and a stack trace,
+  // and the remedies are in three different places.
+  assert.match(whyItFailed("shop.price", new Error("no responders")), /nothing serves shop\.price/);
+  assert.match(
+    whyItFailed("shop.price", new Error("Permissions Violation for Publish")),
+    /may not call shop\.price/,
+  );
+  assert.match(whyItFailed("shop.price", new Error("timeout")), /did not answer in time/);
+  assert.match(whyItFailed("shop.price", new Error("something else")), /something else/);
+});
+
+test("a role's tool is reached through the seat, and a module's own name is never shadowed", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const { seatsIn, toolKey } = await import("../dist/client.js");
+  const mesh = await aMeshWithTools();
+  const person = await connectNats({ url, module: "person.ada" });
+  try {
+    const roles = seatsIn(await toolsOn(person));
+    assert.equal(toolKey("mesh-controller.status", roles), "seat:mesh-controller.status");
+    assert.equal(toolKey("mesh-controller.other", roles), "mesh-controller.other", "a verb the seat does not declare is a module's");
+    assert.equal(toolKey("shop.price", roles), "shop.price");
+    const answer = await callTool(person, "mesh-controller.status", {}, roles);
+    assert.deepEqual(answer.result, { output: "all quiet", ok: true });
+    const direct = await callTool(person, "seat:mesh-controller.status", {});
+    assert.deepEqual(direct.result, { output: "all quiet", ok: true });
+  } finally {
+    await person.close();
+    await mesh.close();
+  }
+});
+
+// A module on two machines (novox/hq ADR 0159): a call names the machine and reaches that instance
+// and no other; a call that names none reaches one of them and says which; a seat's verb is served
+// by the claimant's tool of the same name on the seat's own subject.
+test("a tool call names the machine it is for, and every answer says which machine answered", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const onAnchor = await connectNats({ url: url!, module: "store", node: "anchor" });
+  const onHome = await connectNats({ url: url!, module: "store", node: "home-server" });
+  const asker = await connectNats({ url: url!, module: "console", node: "workstation" });
+  try {
+    await onAnchor.handle("databases", async () => ({ at: "anchor" }));
+    await onHome.handle("databases", async () => ({ at: "home-server" }));
+
+    const home = await callTool(asker, "store.databases@home-server", {});
+    assert.deepEqual(home.result, { at: "home-server" });
+    assert.equal(home.node, "home-server");
+    const anchor = await callTool(asker, "store.databases@anchor", {});
+    assert.deepEqual(anchor.result, { at: "anchor" });
+    assert.equal(anchor.node, "anchor");
+
+    const whichever = await callTool(asker, "store.databases", {});
+    assert.ok(["anchor", "home-server"].includes(whichever.node ?? ""), `an unnamed call still says who answered: ${whichever.node}`);
+    assert.deepEqual(whichever.result, { at: whichever.node });
+
+    // A seat's verb, served by the claimant on the seat's subject; a mesh seat's is flat.
+    await onAnchor.handleSubject("mesh.seat.mesh-store.tool.databases", async () => ({ seat: "mesh-store", at: "anchor" }));
+    const viaSeat = await callTool(asker, "seat:mesh-store.databases", {});
+    assert.deepEqual(viaSeat.result, { seat: "mesh-store", at: "anchor" });
+    assert.equal(viaSeat.node, "anchor");
+  } finally {
+    await onAnchor.close();
+    await onHome.close();
+    await asker.close();
+  }
+});

node-tools/test/conformance.mjs

@@ -0,0 +1,54 @@
+// The TypeScript implementation, held to the shared fixtures (novox/hq ADR 0074, design 19).
+//
+// Run against a NATS server, because the question is what actually reaches the wire:
+//
+//   docker run -d --rm --name c -p 14222:4222 nats:2.10-alpine -js
+//   node test/conformance.mjs
+//
+// **The runner lives with the implementation it exercises; the fixture does not.** It is read
+// from the sdk's conformance directory by sibling path — the same file the Go suite reads. A
+// fixture copied into each implementation is two fixtures, and two fixtures drift, which is the
+// failure the suite exists to prevent.
+import { readFileSync } from "node:fs";
+import { connect } from "nats";
+
+const clientPath = process.argv[2] ?? "../dist/broker-nats.js";
+const { connectNats } = await import(clientPath);
+const f = JSON.parse(readFileSync(new URL("../../mesh-sdk/conformance/events/module-event.json", import.meta.url)));
+const URL_ = process.env.MESH_TEST_NATS ?? "nats://127.0.0.1:14222";
+
+let failed = 0;
+const check = (ok, what) => { console.log(`  ${ok ? "ok  " : "FAIL"}  ${what}`); if (!ok) failed++; };
+
+const admin = await connect({ servers: URL_ });
+const jsm = await admin.jetstreamManager();
+await jsm.streams.add({ name: "EVENTS", subjects: ["mesh.mod.*.event.>", "mesh.seat.*.event.>"] });
+
+const shop = await connectNats({ url: URL_, node: f.given.node, module: f.given.module });
+await shop.publish({ key: f.given.key, node: f.given.node, body: f.given.body, headers: f.given.headers });
+
+// What actually landed, read back from the stream rather than from the client that wrote it.
+const msg = await jsm.streams.getMessage("EVENTS", { last_by_subj: f.wire.subject });
+check(!!msg, `it lands on ${f.wire.subject}`);
+
+if (msg) {
+  const got = {};
+  if (msg.header) for (const k of msg.header.keys()) got[k] = msg.header.get(k);
+  for (const h of f.wire.requiredHeaders) {
+    check(got[h] !== undefined && got[h] !== "", `${h} is set`);
+  }
+  check(got["content-type"] === f.wire.headerFormats["content-type"], "content-type is as pinned");
+  check(new RegExp(f.wire.headerFormats["x-event-id"]).test(got["x-event-id"]), "x-event-id is as pinned");
+  check(!Number.isNaN(Date.parse(got["x-time"])), "x-time parses as a date");
+  check(got["x-source"] === f.given.module, "x-source agrees with the subject's module");
+
+  const payload = JSON.parse(new TextDecoder().decode(msg.data));
+  check(payload.envelope === undefined && payload.key === undefined,
+    "the payload is the body alone, not the envelope (the fixture refuses nesting)");
+  check(JSON.stringify(payload) === JSON.stringify(f.given.body),
+    "the body round-trips — semantic, not byte-exact, per the README");
+}
+
+await shop.close(); await admin.close();
+console.log(failed ? `\n${failed} failed` : "\nall passed");
+process.exit(failed ? 1 : 0);

node-tools/test/fixtures/caller-echo.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+# A tools bundle that says who the runtime said called it (novox/hq issue 365): MCP over stdio, no SDK. Its tool
+# and its seat verb answer the caller the call's `_meta` named — "" when it named none — and the arguments as given.
+import json, sys
+
+def say(m):
+    m["jsonrpc"] = "2.0"; sys.stdout.write(json.dumps(m) + "\n"); sys.stdout.flush()
+
+TOOLS = [
+    {"name": "who", "description": "who called", "inputSchema": {"type": "object", "properties": {}}},
+    {"name": "node-desk.who", "description": "who called the seat's verb", "inputSchema": {"type": "object", "properties": {}}},
+]
+for line in sys.stdin:
+    req = json.loads(line); rid = req.get("id"); m = req.get("method"); p = req.get("params") or {}
+    if m == "initialize":
+        say({"id": rid, "result": {"protocolVersion": "2025-03-26", "capabilities": {"tools": {}}, "serverInfo": {"name": "ledger", "version": "1"}}})
+    elif m == "tools/list":
+        say({"id": rid, "result": {"tools": TOOLS}})
+    elif m == "tools/call":
+        meta = p.get("_meta") or {}
+        said = {"caller": meta.get("mesh/caller", ""), "arguments": p.get("arguments") or {}}
+        say({"id": rid, "result": {"content": [{"type": "text", "text": json.dumps(said)}]}})
+    elif rid is not None:
+        say({"id": rid, "result": {}})

node-tools/test/fixtures/clash-tools.mjs

@@ -0,0 +1,6 @@
+// A module naming a tool after the verb the runtime answers for every module — refused at load.
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+
+registerModuleTools("clash", () => [
+  { name: "tools", description: "mine, not the runtime's", input: {}, run: async () => ({}) },
+]);

node-tools/test/fixtures/clash-tools.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for clash-tools.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./clash-tools.mjs");
+await serveRegisteredOverStdio();

node-tools/test/fixtures/env-delta.mjs

@@ -0,0 +1,4 @@
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+registerModuleTools("delta", (env) => [
+  { name: "given", description: "what delta was given", input: {}, run: async () => ({ mine: env.DELTA_TOKEN_FILE ?? null, theirs: env.GAMMA_CONFIG_FILE ?? null }) },
+]);

node-tools/test/fixtures/env-delta.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for env-delta.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./env-delta.mjs");
+await serveRegisteredOverStdio();

node-tools/test/fixtures/env-gamma.mjs

@@ -0,0 +1,5 @@
+// A bundle that reads what it was given (novox/hq ADR 0192): its contributor's environment.
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+registerModuleTools("gamma", (env) => [
+  { name: "given", description: "what gamma was given", input: {}, run: async () => ({ mine: env.GAMMA_CONFIG_FILE ?? null, theirs: env.DELTA_TOKEN_FILE ?? null, runtime: env.MESH_OPERATOR_ACCOUNT ?? null, composed: env.MESH_TOOL_ENV ?? null }) },
+]);

node-tools/test/fixtures/env-gamma.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for env-gamma.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./env-gamma.mjs");
+await serveRegisteredOverStdio();

node-tools/test/fixtures/env-zeta.mjs

@@ -0,0 +1,6 @@
+#!/usr/bin/env node
+// Launched (ADR 0188): its environment is the child's own.
+import { serveStdio } from "@novox/mesh-sdk/stdio";
+await serveStdio("zeta", [
+  { name: "given", description: "what zeta was given", input: {}, run: async () => ({ mine: process.env.ZETA_URL ?? null, theirs: process.env.GAMMA_CONFIG_FILE ?? null, composed: process.env.MESH_TOOL_ENV ?? null }) },
+]);

node-tools/test/fixtures/flaky.serve.mjs

@@ -0,0 +1,7 @@
+#!/usr/bin/env node
+// A long-running bundle that keeps exiting (novox/hq ADR 0198): the runtime starts it again each time.
+import { appendFileSync } from "node:fs";
+import { serveStdio } from "@novox/mesh-sdk/stdio";
+appendFileSync(process.env.FLAKY_LOG, "started\n");
+setTimeout(() => process.exit(3), 300);
+await serveStdio("flaky", []);

node-tools/test/fixtures/many-alpha.mjs

@@ -0,0 +1,9 @@
+// One of several bundles the node's runtime loads (novox/hq ADR 0175): a module with two tools.
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+import { emit } from "@novox/mesh-sdk/events";
+
+registerModuleTools("alpha", () => [
+  { name: "one", description: "alpha's first", input: {}, run: async () => ({ alpha: 1 }) },
+  // A tool that emits: the event must land on alpha's subject, not the runtime's.
+  { name: "two", description: "alpha's second, which emits", input: {}, run: async () => { await emit("happened", { by: "alpha" }); return { alpha: 2 }; } },
+]);

node-tools/test/fixtures/many-alpha.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for many-alpha.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./many-alpha.mjs");
+await serveRegisteredOverStdio();

node-tools/test/fixtures/many-beta.mjs

@@ -0,0 +1,14 @@
+// One of several bundles the node's runtime loads (novox/hq ADR 0175): a module with three tools of
+// its own and the implementation of a node seat's two verbs under the seat's name (ADR 0159).
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+
+registerModuleTools("beta", () => [
+  { name: "three", description: "beta's", input: { verbose: { type: "boolean", description: "say more" } }, run: async () => ({ beta: 3 }) },
+  { name: "four", description: "beta's", input: {}, run: async () => ({ beta: 4 }) },
+  { name: "five", description: "beta's", input: {}, run: async () => ({ beta: 5 }) },
+]);
+
+registerModuleTools("node-shelf", () => [
+  { name: "list", description: "what is on the shelf", input: {}, run: async () => ({ shelf: ["a", "b"] }) },
+  { name: "clear", description: "take it all off", input: {}, run: async () => ({ cleared: true }) },
+]);

node-tools/test/fixtures/many-beta.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for many-beta.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./many-beta.mjs");
+await serveRegisteredOverStdio();

node-tools/test/fixtures/many-broken.mjs

@@ -0,0 +1,3 @@
+// A bundle that throws on import — the fault ADR 0175 names as what got harder: one module's bundle
+// must not take the node's other tools down.
+throw new Error("gamma's bundle cannot find its client");

node-tools/test/fixtures/many-broken.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for many-broken.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./many-broken.mjs");
+await serveRegisteredOverStdio();

node-tools/test/fixtures/many-delta.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+# A tools bundle in a second language (novox/hq ADR 0188): MCP over stdio, no SDK, no dependencies.
+# One tool of its own, one seat verb, and one that exits the process mid-call.
+import json, sys
+
+def say(m):
+    m["jsonrpc"] = "2.0"; sys.stdout.write(json.dumps(m) + "\n"); sys.stdout.flush()
+
+TOOLS = [
+    {"name": "greet", "description": "say hello", "inputSchema": {"type": "object", "properties": {"who": {"type": "string"}}}},
+    {"name": "node-lamp.on", "description": "the seat's verb", "inputSchema": {"type": "object", "properties": {}}},
+    {"name": "die", "description": "exit without answering", "inputSchema": {"type": "object", "properties": {}}},
+]
+for line in sys.stdin:
+    req = json.loads(line); rid = req.get("id"); m = req.get("method"); p = req.get("params") or {}
+    if m == "initialize":
+        say({"id": rid, "result": {"protocolVersion": "2025-03-26", "capabilities": {"tools": {}}, "serverInfo": {"name": "delta", "version": "1"}}})
+    elif m == "tools/list":
+        say({"id": rid, "result": {"tools": TOOLS}})
+    elif m == "tools/call":
+        name = p.get("name"); args = p.get("arguments") or {}
+        if name == "greet":
+            say({"id": rid, "result": {"content": [{"type": "text", "text": json.dumps({"greeting": "hello " + args.get("who", "world"), "language": "python"})}]}})
+        elif name == "node-lamp.on":
+            say({"id": rid, "result": {"content": [{"type": "text", "text": json.dumps({"on": True, "language": "python"})}]}})
+        elif name == "die":
+            print("delta: told to die", file=sys.stderr); sys.exit(3)
+        else:
+            say({"id": rid, "error": {"code": -32602, "message": "no such tool"}})

node-tools/test/fixtures/many-epsilon.mjs

@@ -0,0 +1,8 @@
+#!/usr/bin/env node
+// A TypeScript bundle written against the protocol and marked executable: served through the
+// launcher like any other language, with the in-process shortcut off (novox/hq ADR 0188).
+import { serveStdio } from "@novox/mesh-sdk/stdio";
+
+await serveStdio("epsilon", [
+  { name: "seven", description: "epsilon's", input: {}, run: async () => ({ epsilon: 7, via: "stdio" }) },
+]);

node-tools/test/fixtures/refusing-nats.conf

@@ -0,0 +1,10 @@
+# A bus that refuses one subject: what the mesh's grants do to a subject they do not name (issue 217).
+authorization {
+  users = [
+    { user: "runtime", password: "runtime", permissions: {
+        publish: { allow: [">"] }
+        subscribe: { allow: [">"], deny: ["$SRV.PING.>", "mesh.seat.held-elsewhere.>"] }
+    } }
+  ]
+}
+jetstream: enabled

node-tools/test/fixtures/served-seat-first.mjs

@@ -0,0 +1,8 @@
+#!/usr/bin/env node
+// A launched bundle registering its seat before its own tools, served through the SDK's loop
+// (novox/hq ADR 0193): which is the seat's and which the module's comes from the name it is given.
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+registerModuleTools("node-shelf", () => [{ name: "list", description: "the shelf", input: {}, run: async () => ({ shelf: ["x"] }) }]);
+registerModuleTools("theta", (env) => [{ name: "own", description: "theta's", input: {}, run: async () => ({ theta: env.THETA_WORD ?? null }) }]);
+await serveRegisteredOverStdio();

node-tools/test/fixtures/shop-seat.mjs

@@ -0,0 +1,12 @@
+// The shop again, in a file of its own: a module imported once stays imported, so a second test needs a second entrypoint.
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+
+registerModuleTools("shop", () => [
+  {
+    name: "price",
+    description: "what something costs",
+    input: { of: { type: "string", description: "the thing" } },
+    run: async (args) => ({ of: args.of ?? "nothing", cost: 12 }),
+  },
+  { name: "refund", description: "give it back", input: {}, run: async () => ({ done: true }) },
+]);

node-tools/test/fixtures/shop-seat.serve.mjs

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+// The launcher the builder writes beside an entrypoint (novox/hq ADR 0193), for shop-seat.mjs.
+import { serveRegisteredOverStdio } from "@novox/mesh-sdk/stdio";
+await import("./shop-seat.mjs");
+await serveRegisteredOverStdio();