One SDK per runtime: a bundle's SDK import resolves to the runtime's copy (hq issue 209)

A bundle carries its dependencies, the SDK among them; imported in-process that copy was a
second SDK with its own tool registry, so a bundle registered its tools into a list the
runtime never read and served nothing, silently. A resolve hook now sends every import of
@novox/mesh-sdk, from whichever bundle, to the runtime's own copy: one registry, one broker.
The test loads a bundle from a directory holding its own SDK copy and sees its tool served.

.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 +22,42 @@ 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
 
-# ---- 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 ---------------------------------------
+# 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.
+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
+
+# ---- 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 +1,76 @@
 # 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.
+
+Discovery asks the modules: every runtime answers a `tools` verb for each module it serves, with names,
+descriptions and schemas from the code that answers them, and the console asks the catalogue which
+modules the mesh holds and each module what it serves. A module that does not answer is named, never
+dropped. 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)}`);
-  }
-}

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/module.json

@@ -0,0 +1,45 @@
+{
+  "module": "node-tools",
+  "version": "1",
+  "slug": "node-tools",
+  "invokes": [
+    "*"
+  ],
+  "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": "typescript",
+        "entrypoints": [
+          "src/main.js"
+        ]
+      }
+    ]
+  }
+}

node-tools/src/broker-nats.ts

@@ -16,6 +16,7 @@
 // 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";
@@ -40,6 +41,77 @@ export interface Credential {
   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;
+}
+
+/**
+ * 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
@@ -69,7 +141,7 @@ export function fatalBrokerReason(err: unknown): string | null {
 export async function connectNats(
   target: string | Credential,
   opts: { module?: string } = {},
-): Promise<Broker> {
+): Promise<RuntimeBroker> {
   const cred: Credential = typeof target === "string" ? { url: target } : target;
   const self = cred.module ?? opts.module;
   if (!self) {
@@ -102,36 +174,104 @@ export async function connectNats(
   let reading: Awaited<ReturnType<Awaited<ReturnType<typeof js.consumers.get>>["consume"]>> | undefined;
   let closed = false;
 
-  return {
+  const node = cred.node;
-    /**
-     * Ask one question and await one answer.
-     *
-     * 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.
-     */
-    async request<Req, Res>(key: string, body: Req): Promise<Res> {
-      const msg = await conn.request(toolSubject(key, self), sc.encode(JSON.stringify(body)), {
-        timeout: REQUEST_TIMEOUT_MS,
-      });
-      const reply = JSON.parse(sc.decode(msg.data)) as { result?: Res; error?: string };
-      if (reply.error) throw new Error(reply.error);
-      return reply.result as Res;
-    },
 
-    /**
+  // The memberships, one per module this connection serves, each read once and followed. A
-     * Answer a question.
+  // 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
-     * A queue group, so several nodes may serve one tool and exactly one of them answers each
+  // modules, and nothing on the bus learns a new shape for it. A direct get is one request on the
-     * call.
+  // 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
-    async handle<Req, Res>(key: string, handler: (body: Req) => Promise<Res>): Promise<() => void> {
+  // retry.
-      const sub = conn.subscribe(toolSubject(key, self), { queue: `serve.${self}` });
+  const issued = new Map<string, Membership | undefined>();
+  const issuedHandlers: ((m: Membership) => void)[] = [];
+  const follow = async (module: string): Promise<void> => {
+    if (!node || issued.has(module)) return;
+    issued.set(module, undefined);
+    const subjectOfTheirs = membershipSubject(node, module);
+    try {
+      // The subject-addressed form of a direct get — the stream, then the subject, nothing in
+      // the body — because that is the one address the mesh grants this account on the
+      // stream's API; the body form asks the stream's root, which it may not.
+      const got = await conn.request(`$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 () => {
       for await (const msg of sub) {
-          let reply: { result?: Res; error?: string };
+        let reply: { result?: Res; error?: string; node?: string };
         try {
           reply = { result: await handler(JSON.parse(sc.decode(msg.data)) as Req) };
         } catch (err) {
@@ -139,12 +279,84 @@ export async function connectNats(
           // 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)));
       }
     })();
-      return () => {
+    return () => sub.unsubscribe();
-        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,
+    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);
     },
 
     /**
@@ -169,7 +381,9 @@ export async function connectNats(
       if (!meta["content-type"]) h.set("content-type", "application/json");
       if (env.node) h.set("x-node", env.node);
 
-      await js.publish(eventSubject(env.key, self), sc.encode(JSON.stringify(env.body)), {
+      // 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.
@@ -313,11 +527,33 @@ function eventSubject(type: string, self: string): string {
 }
 
 /** 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. */
+ *  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 {
-  const dot = key.indexOf(".");
+  if (key.startsWith("seat:")) {
-  if (dot < 0) return `mesh.mod.${self}.tool.${key}`;
+    const rest = key.slice("seat:".length);
-  return `mesh.mod.${key.slice(0, dot)}.tool.${key.slice(dot + 1)}`;
+    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 {

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 +1,169 @@
+// 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";
+
+/** 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; 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: ${line.slice(0, 120)}`);
+          continue;
+        }
+        const waiting = typeof reply.id === "number" ? pending.get(reply.id) : undefined;
+        if (!waiting) continue;
+        pending.delete(reply.id!);
+        clearTimeout(waiting.timer);
+        if (reply.error) waiting.reject(new Error(reply.error.message ?? "the bundle refused the request"));
+        else waiting.resolve(reply.result);
+      }
+    });
+    // stderr is the bundle's log; kept under the module's name so a fault reads where it belongs.
+    proc.stderr!.on("data", (chunk: Buffer) => {
+      for (const line of chunk.toString("utf8").split("\n")) if (line.trim()) console.log(`[${module}] ${line}`);
+    });
+    const exited = new Promise<never>((_, reject) => {
+      proc.once("error", (err) => reject(err));
+      proc.once("exit", (code, signal) => {
+        const why = `${module}'s bundle exited (${signal ?? code})`;
+        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

@@ -1,7 +1,7 @@
 // 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.
@@ -21,14 +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 { connectNats, fatalBrokerReason as fatalNatsReason, type Credential } from "./broker-nats.js";
-import { runTools } from "./runtime.js";
+import { runTools, type ServedModule } 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";
@@ -51,6 +56,7 @@ async function connectBroker(): Promise<Broker> {
     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);
@@ -114,17 +120,66 @@ 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);
+  const stop = await runTools({ broker, serves, moduleEntrypoints, credential: lastCredential });
+
+  // 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);
   };
@@ -246,4 +301,7 @@ async function main(): Promise<void> {
   await serve();
 }
 
+// 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 +1,327 @@
+// 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 { register } from "node:module";
+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";
+
+/**
+ * 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;
+}
+
+/** 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]);
+  }
+  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);
+  }
+
+  // Import each bundle, guarded (ADR 0175: one faulty bundle must not take the node's tools down).
+  // Importing the entrypoint runs its registerModuleTools(...) — that is the whole handshake — and
+  // the registrations it adds are the ones that appear after it, which is how each is attributed
+  // to the module whose bundle made it.
+  // A bundle that is not plain JavaScript — or is marked executable — is launched as a process
+  // and spoken to over MCP on stdio instead (ADR 0188); what it lists is registered the same way.
+  // Every bundle's import of the SDK resolves to this runtime's copy (04-ISSUES/209): one registry
+  // of tools, one broker. Installed before the first bundle is imported.
+  oneSdk();
+  const failed = new Map<string, string>();
+  const owner: string[] = []; // registration index → the module whose bundle registered it
+  const launched: { module: string; owner: string; tools: ToolDefinition[] }[] = [];
+  const children: Array<() => void> = [];
+  for (const [module, entrypoints] of served) {
+    for (const entry of entrypoints) {
+      const path = resolve(entry);
+      try {
+        if (launches(path)) {
+          const child = await launch(module, path);
+          children.push(child.stop);
+          for (const r of child.registrations) launched.push({ ...r, owner: module });
+          continue;
+        }
+        const before = collectTools().length;
+        await import(pathToFileURL(path).href);
+        const after = collectTools().length;
+        for (let i = before; i < after; i++) owner[i] = 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, i) => ({ ...r, owner: owner[i] ?? 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` : ""));
+  stops.push(await serveClaimedSeats(runtime, [...served.keys()], self, opts.credential, registrations));
+  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<() => void> {
+  if (typeof broker.handleSubject !== "function") return () => {};
+  // 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>>>();
+  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: where the mesh issued the verb when
+      // it has; the derived shape until then.
+      if (module !== self) continue;
+      for (const claim of credential?.claims ?? []) {
+        for (const verb of claim.serves ?? []) {
+          const subject = m?.seats?.find((s) => s.seat === claim.seat && s.verb === verb)?.subject
+            ?? seatToolSubject(claim.seat, verb, claim.scope, credential?.node);
+          add({ seat: claim.seat, verb, subject, holder: module });
+        }
+      }
+    }
+    return out;
+  };
+
+  let stops: (() => void)[] = [];
+  const serve = async (): Promise<void> => {
+    stops.forEach((s) => s());
+    stops = [];
+    for (const v of wanted()) {
+      const run = implementations.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));
+      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 () => stops.forEach((s) => s());
+}
+
+let sdkHooked = false;
+/** Resolve `@novox/mesh-sdk` for every bundle to the copy this runtime imported (sdk-hooks.ts). */
+function oneSdk(): void {
+  if (sdkHooked) return;
+  sdkHooked = true;
+  register("./sdk-hooks.js", { parentURL: import.meta.url, data: { runtimeURL: import.meta.url } });
+}

node-tools/src/sdk-hooks.ts

@@ -0,0 +1,38 @@
+// The one SDK in a node's runtime (novox/hq ADR 0175, 04-ISSUES/209).
+//
+// A bundle carries its own dependencies — the toolchain copies them in so a bundle starts anywhere
+// (to-be 38 WP3) — and among them is a copy of @novox/mesh-sdk. Imported in this process, that copy
+// would be a second SDK: its own registry of tools, its own broker handle. A bundle calling
+// registerModuleTools through it registers into a list this runtime never reads, and its tools are
+// silently not served. So every import of the SDK, from whichever bundle, is resolved as if this
+// runtime had written it: one registry, one broker — the runtime's. Everything else a bundle
+// carries resolves from the bundle's own tree, as before.
+//
+// Installed through module.register(), whose resolve hook sees every import that follows.
+
+interface ResolveContext {
+  parentURL?: string;
+  conditions: string[];
+  importAttributes: Record<string, string>;
+}
+interface Resolved {
+  url: string;
+  format?: string | null;
+  shortCircuit?: boolean;
+}
+type NextResolve = (specifier: string, context?: Partial<ResolveContext>) => Promise<Resolved>;
+
+const SDK = "@novox/mesh-sdk";
+let runtimeURL = "";
+
+/** Told, once, which file's tree holds the runtime's SDK. */
+export function initialize(data: { runtimeURL: string }): void {
+  runtimeURL = data.runtimeURL;
+}
+
+export async function resolve(specifier: string, context: ResolveContext, next: NextResolve): Promise<Resolved> {
+  if (runtimeURL && (specifier === SDK || specifier.startsWith(SDK + "/"))) {
+    return next(specifier, { ...context, parentURL: runtimeURL });
+  }
+  return next(specifier, context);
+}

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/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/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-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: {}, 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-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-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/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-tools.mjs

@@ -0,0 +1,12 @@
+// A module's tool entrypoint, as the runtime imports one: registers and returns.
+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/store-seat-unclaimed.mjs

@@ -0,0 +1,12 @@
+// A module that is both software and a role: postgres's own tools under its name, and its
+// implementation of the mesh-store seat's verbs under the seat's (novox/hq ADR 0159, 0160).
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+
+registerModuleTools("postgres", () => [
+  { name: "postgres_create_database", description: "make one", input: {}, run: async () => ({ made: true }) },
+  { name: "databases", description: "postgres's own listing", input: {}, run: async () => ({ software: "postgres" }) },
+]);
+
+registerModuleTools("mesh-store", () => [
+  { name: "databases", description: "what the store holds", input: {}, run: async () => ({ seat: "mesh-store" }) },
+]);

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

@@ -0,0 +1,12 @@
+// A module that is both software and a role: postgres's own tools under its name, and its
+// implementation of the mesh-store seat's verbs under the seat's (novox/hq ADR 0159, 0160).
+import { registerModuleTools } from "@novox/mesh-sdk/tools";
+
+registerModuleTools("postgres", () => [
+  { name: "postgres_create_database", description: "make one", input: {}, run: async () => ({ made: true }) },
+  { name: "databases", description: "postgres's own listing", input: {}, run: async () => ({ software: "postgres" }) },
+]);
+
+registerModuleTools("mesh-store", () => [
+  { name: "databases", description: "what the store holds", input: {}, run: async () => ({ seat: "mesh-store" }) },
+]);

node-tools/test/http.test.ts

@@ -0,0 +1,113 @@
+/**
+ * The console: the same surface over HTTP on loopback, started the way the mesh starts it — on the
+ * module credential in MESH_BROKER_FILE (novox/hq ADR 0152, design 34 §2).
+ *
+ *   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/http.test.ts
+ */
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { spawn, type ChildProcess } from "node:child_process";
+import { mkdtemp, writeFile } from "node:fs/promises";
+import { join } from "node:path";
+
+import { connectNats } from "../dist/broker-nats.js";
+import { serveMcpHttp } from "../dist/http.js";
+
+const url = process.env.MESH_TEST_NATS;
+
+async function aMesh(t: { after: (fn: () => Promise<void> | void) => void }) {
+  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" }] }));
+  await shop.handle("tools", async () => ({
+    module: "shop",
+    tools: [{ name: "price", description: "what something costs", input: {} }],
+  }));
+  await shop.handle("price", async (body: { of?: string }) => ({ of: body.of ?? "nothing", cost: 12 }));
+  t.after(async () => {
+    await catalogue.close();
+    await shop.close();
+  });
+}
+
+/** `mesh serve` as the mesh runs it: MESH_BROKER_FILE, a listen address, nothing else. */
+async function aConsole(t: { after: (fn: () => Promise<void> | void) => void }): Promise<string> {
+  const dir = await mkdtemp("/tmp/mesh-console-");
+  const credential = join(dir, "broker");
+  await writeFile(credential, JSON.stringify({ url, node: "desk", module: "mesh-console", user: "desk.mesh-console", password: "x" }));
+  const child: ChildProcess = spawn(process.execPath, ["dist/mesh.js", "serve", "--listen", "127.0.0.1:0"], {
+    env: { ...process.env, MESH_BROKER_FILE: credential, MESH_CREDENTIAL: "" },
+    stdio: ["ignore", "pipe", "pipe"],
+  });
+  t.after(() => {
+    child.kill("SIGTERM");
+  });
+  return new Promise((resolve, reject) => {
+    let out = "";
+    let err = "";
+    child.stdout!.on("data", (d) => {
+      out += d.toString();
+      const m = /listening on (http:\/\/[^/]+\/mcp)/.exec(out);
+      if (m) resolve(m[1]!);
+    });
+    child.stderr!.on("data", (d) => (err += d.toString()));
+    child.on("exit", (code) => reject(new Error(`serve exited ${code}: ${err}`)));
+  });
+}
+
+async function post(endpoint: string, body: unknown): Promise<{ status: number; json?: any }> {
+  const res = await fetch(endpoint, {
+    method: "POST",
+    headers: { "content-type": "application/json", accept: "application/json" },
+    body: JSON.stringify(body),
+  });
+  const text = await res.text();
+  return { status: res.status, json: text ? JSON.parse(text) : undefined };
+}
+
+test("the console answers a host on loopback, as the account the mesh gave it", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  await aMesh(t);
+  const endpoint = await aConsole(t);
+
+  const hello = await post(endpoint, { jsonrpc: "2.0", id: 1, method: "initialize", params: {} });
+  assert.equal(hello.status, 200);
+  assert.match(hello.json.result.instructions, /desk\.mesh-console/, "the handshake names the console's account");
+
+  const heard = await post(endpoint, { jsonrpc: "2.0", method: "notifications/initialized" });
+  assert.equal(heard.status, 202, "a notification is heard and not answered");
+
+  const listed = await post(endpoint, { jsonrpc: "2.0", id: 2, method: "tools/list" });
+  assert.deepEqual(listed.json.result.tools.map((x: { name: string }) => x.name), ["shop.price"]);
+
+  const called = await post(endpoint, {
+    jsonrpc: "2.0", id: 3, method: "tools/call", params: { name: "shop.price", arguments: { of: "a hat" } },
+  });
+  assert.deepEqual(JSON.parse(called.json.result.content[0].text), { of: "a hat", cost: 12 });
+
+  // A person's client through the same endpoint, with no credential of its own.
+  const { main } = await import("../dist/mesh.js");
+  const logged: string[] = [];
+  const was = console.log;
+  console.log = (line: string) => logged.push(String(line));
+  try {
+    assert.equal(await main(["tools", "--console", endpoint]), 0);
+  } finally {
+    console.log = was;
+  }
+  assert.ok(logged.some((l) => l.startsWith("shop.price")), `the client did not list through the console: ${logged}`);
+});
+
+test("the console binds loopback and nowhere else", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const bus = await connectNats({ url, module: "mesh-console", node: "desk" });
+  try {
+    await assert.rejects(() => serveMcpHttp(bus, "desk.mesh-console", "0.0.0.0:0"), /loopback and nowhere else/);
+    const up = await serveMcpHttp(bus, "desk.mesh-console", "127.0.0.1:0");
+    assert.match(up.address, /^127\.0\.0\.1:\d+$/);
+    await up.close();
+  } finally {
+    await bus.close();
+  }
+});

node-tools/test/mcp.test.ts

@@ -20,13 +20,32 @@ const url = process.env.MESH_TEST_NATS;
 async function aMeshAndACredential(t: { after: (fn: () => Promise<void> | void) => void }) {
   const catalogue = await connectNats({ url: url!, module: "mesh-catalog" });
   const shop = await connectNats({ url: url!, module: "shop" });
-  await catalogue.handle("catalog_tools", async () => ({
+  await catalogue.handle("catalog_modules", async () => ({
-    tools: [{ module: "shop", name: "price", description: "what something costs" }],
+    modules: [{ module: "shop" }, { module: "ghost" }],
+  }));
+  await shop.handle("tools", async () => ({
+    module: "shop",
+    tools: [{ name: "price", description: "what something costs", input: { of: { type: "string" } } }],
   }));
   await shop.handle("price", async (body: { of?: string }) => ({ of: body.of ?? "nothing", cost: 12 }));
+  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: {} },
+        { name: "push", description: "tell a machine", input: { node: { type: "string" } } },
+      ] },
+      // A seat held once per machine (design 33 §4, ADR 0170): its verb is asked of one.
+      { seat: "node-dns-resolver", scope: "node", tools: [{ name: "lookup", description: "one machine's", input: {} }] },
+    ],
+  }));
+  await controller.handle("seat:node-dns-resolver.lookup@anchor", async () => ({ machine: "anchor", answered: true }));
+  await controller.handle("seat:mesh-controller.status", async () => ({ output: "all quiet", ok: true }));
+  await controller.handle("seat:mesh-controller.push", async (body: { node?: string }) => ({ told: body.node ?? "nobody" }));
   t.after(async () => {
     await catalogue.close();
     await shop.close();
+    await controller.close();
   });
 
   const { mkdtemp, writeFile } = await import("node:fs/promises");
@@ -80,14 +99,28 @@ test("a host initialises, lists the mesh's tools and calls one", async (t) => {
   assert.equal(replies.length, 3, `expected three replies, got ${JSON.stringify(replies)}`);
 
   const hello = byId.get(1)!.result;
-  assert.equal(hello.protocolVersion, "2024-11-05");
+  assert.equal(hello.protocolVersion, "2025-03-26");
   assert.ok(hello.capabilities.tools, "a server offering no tools is not this one");
   assert.match(hello.instructions, /ada/, "the handshake says whose authority a call is made under");
 
   const listed = byId.get(2)!.result.tools;
-  assert.equal(listed.length, 1);
+  assert.deepEqual(listed.map((x: { name: string }) => x.name),
-  assert.equal(listed[0].name, "shop.price", "a tool is named the way a person names it");
+    ["mesh-controller.push", "mesh-controller.status", "node-dns-resolver.lookup", "shop.price"],
-  assert.ok(listed[0].inputSchema, "a tool with no schema is one an agent cannot call");
+    "the modules' tools and the roles', named the way a person names them");
+  // A node-scoped seat's verb takes the machine, and requires it (ADR 0170).
+  const lookup = listed[2];
+  assert.equal(lookup.inputSchema.properties.node.type, "string");
+  assert.deepEqual(lookup.inputSchema.required, ["node"]);
+  const price = listed[3];
+  assert.ok(price.inputSchema, "a tool with no schema is one an agent cannot call");
+  // A module's bare property map arrives as a schema an agent can read, its words kept — and
+  // `node`, the machine to ask when the module runs on several (novox/hq ADR 0159), beside them.
+  assert.deepEqual(price.inputSchema.properties.of, { type: "string" });
+  assert.equal(price.inputSchema.properties.node.type, "string", "a module's tool takes the machine to ask");
+  assert.ok(!listed[1].inputSchema.properties?.node, "a seat's verb takes no machine; the seat's scope decides");
+  assert.equal(listed[0].inputSchema.properties?.node?.type, "string", "a seat's verb that takes a node of its own keeps it");
+  // Silence is named: the module the catalogue holds and nothing answered for.
+  assert.deepEqual(byId.get(2)!.result._meta.notAnswering, ["ghost"]);
 
   const called = byId.get(3)!.result;
   assert.ok(!called.isError, `the call failed: ${JSON.stringify(called)}`);
@@ -122,3 +155,42 @@ test("a method this surface does not have is refused, and a notification is not"
   assert.equal(replies[0].error.code, -32601);
   assert.match(replies[0].error.message, /resources\/list/);
 });
+
+// A seat's verb that takes a machine as its own argument — `push <node>` — keeps it: the console
+// moves `node` into the subject for a module's tool only (ADR 0159), never for a role's verb.
+test("a seat's verb keeps a node of its own; only a module's tool gives it to the subject", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const credential = await aMeshAndACredential(t);
+  const replies = await driving(credential, [
+    { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "mesh-controller.push", arguments: { node: "anchor" } } },
+  ]);
+  const result = replies[0].result;
+  assert.ok(!result.isError, JSON.stringify(replies[0]));
+  assert.deepEqual(JSON.parse(result.content[0].text), { told: "anchor" });
+});
+
+test("a host calls the mesh's own verb through the seat", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const credential = await aMeshAndACredential(t);
+  const replies = await driving(credential, [
+    { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "mesh-controller.status", arguments: {} } },
+  ]);
+  const result = replies[0].result;
+  assert.ok(!result.isError, JSON.stringify(replies[0]));
+  assert.deepEqual(JSON.parse(result.content[0].text), { output: "all quiet", ok: true });
+});
+
+test("a node-scoped seat's verb is asked of the machine named, and refused without one", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const credential = await aMeshAndACredential(t);
+  const replies = await driving(credential, [
+    { jsonrpc: "2.0", id: 1, method: "initialize", params: {} },
+    { jsonrpc: "2.0", id: 2, method: "tools/call", params: { name: "node-dns-resolver.lookup", arguments: { node: "anchor" } } },
+    { jsonrpc: "2.0", id: 3, method: "tools/call", params: { name: "node-dns-resolver.lookup", arguments: {} } },
+  ]);
+  const byId = new Map(replies.map((r) => [r.id, r]));
+  const answered = byId.get(2)!.result;
+  assert.ok(!answered.isError, JSON.stringify(answered));
+  assert.match(answered.content[0].text, /"machine": "anchor"/, "the machine's holder answered");
+  assert.match(byId.get(3)!.error?.message ?? JSON.stringify(byId.get(3)), /name the machine/);
+});

node-tools/test/membership.test.ts

@@ -0,0 +1,225 @@
+/**
+ * The mesh issues an assignment's subjects, and a runtime serves what it is issued (novox/hq ADR
+ * 0160). A runtime derives one address for itself — `mesh.assignment.<node>.<module>` — reads the
+ * membership there, serves exactly what it says, and re-serves when a new one arrives. Against a
+ * real bus with JetStream, because the membership is a direct get on a stream.
+ *
+ *   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/membership.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 { callTool, subjectListed } from "../dist/client.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();
+
+/** The ASSIGNMENTS stream as the controller asserts it: last-per-subject, readable by direct get. */
+async function anAssignmentsStream() {
+  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);
+  return {
+    async issue(m: object & { node: string; module: string }) {
+      await nc.jetstream().publish(membershipSubject(m.node, m.module), sc.encode(JSON.stringify(m)));
+    },
+    async close() {
+      await nc.close();
+    },
+  };
+}
+
+test("a runtime serves exactly the subjects it is issued, and the listing carries them", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const stream = await anAssignmentsStream();
+  // The mesh placed shop on two machines that are not interchangeable: each is served by name only.
+  await stream.issue({
+    node: "anchor",
+    module: "shop",
+    serves: [{ subject: "mesh.mod.shop.tool.{tool}.anchor" }],
+    emits: "mesh.mod.shop.event.{event}",
+    tools: "mesh.mod.shop.tool.tools",
+  });
+  const shop = await connectNats({ url, node: "anchor", module: "shop" });
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: shop, moduleEntrypoints: [fixture("shop-tools.mjs")] });
+    assert.equal(shop.membership()?.module, "shop", "the runtime read what the mesh issued");
+    // By name it answers; the plain subject was not issued, so nothing serves it.
+    const named = await callTool(asker, "shop.price@anchor", { of: "a hat" });
+    assert.deepEqual(named.result, { of: "a hat", cost: 12 });
+    assert.equal(named.node, "anchor");
+    await assert.rejects(callTool(asker, "shop.price", {}), /no responders|503/i, "a subject not issued is not served");
+    // The tools answer says where each is served, and the client composes nothing.
+    const tools = await asker.request<Record<string, never>, { tools: { name: string; subjects?: string[] }[] }>(
+      "shop.tools",
+      {},
+    );
+    assert.deepEqual(tools.tools.find((x) => x.name === "price")?.subjects, ["mesh.mod.shop.tool.price.anchor"]);
+    const listing = { tools: [{ module: "shop", name: "price", subjects: ["mesh.mod.shop.tool.price.anchor"] }], notAnswering: [] };
+    assert.equal(subjectListed("shop.price", "anchor", listing as never), "mesh.mod.shop.tool.price.anchor");
+    assert.equal(subjectListed("shop.price", "elsewhere", listing as never), undefined);
+
+    // The mesh re-issues the membership with the plain subject too (the modules became
+    // interchangeable); the runtime re-serves on it without a restart.
+    await stream.issue({
+      node: "anchor",
+      module: "shop",
+      serves: [{ subject: "mesh.mod.shop.tool.{tool}", queue: "serve.shop" }, { subject: "mesh.mod.shop.tool.{tool}.anchor" }],
+      emits: "mesh.mod.shop.event.{event}",
+      tools: "mesh.mod.shop.tool.tools",
+    });
+    await new Promise((r) => setTimeout(r, 300));
+    const plain = await callTool(asker, "shop.price", { of: "a coat" });
+    assert.deepEqual(plain.result, { of: "a coat", cost: 12 });
+    assert.equal(plain.node, "anchor");
+  } finally {
+    stop();
+    await asker.close();
+    await shop.close();
+    await stream.close();
+  }
+});
+
+test("a seat's verbs are implemented under the seat's name, served where issued, never listed as the module's", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const stream = await anAssignmentsStream();
+  await stream.issue({
+    node: "anchor",
+    module: "postgres",
+    serves: [{ subject: "mesh.mod.postgres.tool.{tool}", queue: "serve.postgres" }, { subject: "mesh.mod.postgres.tool.{tool}.anchor" }],
+    seats: [{ seat: "mesh-store", verb: "databases", subject: "mesh.seat.mesh-store.tool.databases" }],
+    emits: "mesh.mod.postgres.event.{event}",
+    tools: "mesh.mod.postgres.tool.tools",
+  });
+  const credential = { url, node: "anchor", module: "postgres", claims: [{ seat: "mesh-store", scope: "mesh", serves: ["databases", "query"] }] };
+  const pg = await connectNats(credential);
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: pg, credential, moduleEntrypoints: [fixture("store-seat.mjs")] });
+    // The module's own `databases` and the seat's are two tools: postgres's on its subject, the
+    // store's on the seat's, each answering as itself.
+    const own = await callTool(asker, "postgres.databases", {});
+    assert.deepEqual(own.result, { software: "postgres" });
+    const seat = await callTool(asker, "seat:mesh-store.databases", {});
+    assert.deepEqual(seat.result, { seat: "mesh-store" });
+    assert.equal(seat.node, "anchor");
+    // What the seat does not promise — creating a database — is postgres's tool and not the store's.
+    await assert.rejects(callTool(asker, "seat:mesh-store.postgres_create_database", {}), /no responders|503/i);
+    // And the module's `tools` lists only postgres's own, never the seat's implementation.
+    const tools = await asker.request<Record<string, never>, { module: string; tools: { name: string }[] }>("postgres.tools", {});
+    assert.deepEqual(tools.tools.map((x) => x.name).sort(), ["databases", "postgres_create_database"]);
+    await assert.rejects(asker.request("mesh-store.tools", {}), /no responders|503/i, "a seat is not a module with a tools verb");
+  } finally {
+    stop();
+    await asker.close();
+    await pg.close();
+    await stream.close();
+  }
+});
+
+test("a module named like its seat registers once, and answers as the module and as the seat", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const stream = await anAssignmentsStream();
+  await stream.issue({
+    node: "anchor",
+    module: "shop",
+    serves: [{ subject: "mesh.mod.shop.tool.{tool}", queue: "serve.shop" }, { subject: "mesh.mod.shop.tool.{tool}.anchor" }],
+    seats: [{ seat: "shop", verb: "price", subject: "mesh.seat.shop.tool.price" }],
+    emits: "mesh.mod.shop.event.{event}",
+    tools: "mesh.mod.shop.tool.tools",
+  });
+  const credential = { url, node: "anchor", module: "shop", claims: [{ seat: "shop", scope: "mesh", serves: ["price"] }] };
+  const shop = await connectNats(credential);
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: shop, credential, moduleEntrypoints: [fixture("shop-seat.mjs")] });
+    assert.deepEqual((await callTool(asker, "shop.price", { of: "a hat" })).result, { of: "a hat", cost: 12 });
+    assert.deepEqual((await callTool(asker, "seat:shop.price", { of: "a hat" })).result, { of: "a hat", cost: 12 });
+    const tools = await asker.request<Record<string, never>, { tools: { name: string }[] }>("shop.tools", {});
+    assert.deepEqual(tools.tools.map((x) => x.name), ["price", "refund"]);
+  } finally {
+    stop();
+    await asker.close();
+    await shop.close();
+    await stream.close();
+  }
+});
+
+test("a mesh that has issued nothing yet gets the derived shape, and says so", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  const stream = await anAssignmentsStream();
+  const said: string[] = [];
+  const log = console.log;
+  console.log = (...a: unknown[]) => said.push(a.join(" "));
+  let lone;
+  try {
+    lone = await connectNats({ url, node: "home-server", module: "lone" });
+  } finally {
+    console.log = log;
+  }
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  try {
+    assert.equal(lone.membership(), undefined);
+    assert.ok(said.some((s) => /no membership issued for lone on home-server/.test(s)), said.join("\n"));
+    await lone.handle("ping", async () => ({ pong: true }));
+    assert.deepEqual((await callTool(asker, "lone.ping", {})).result, { pong: true });
+    assert.deepEqual((await callTool(asker, "lone.ping@home-server", {})).result, { pong: true });
+  } finally {
+    await asker.close();
+    await lone.close();
+    await stream.close();
+  }
+});
+
+// A module that implements a seat its credential does not (yet) claim is not served for it and does
+// not fall over either: the runtime says so and serves the module's own tools.
+test("a registration under a seat the credential does not claim is said and skipped, not fatal", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const stream = await anAssignmentsStream();
+  const credential = { url, node: "anchor", module: "postgres" };
+  const pg = await connectNats(credential);
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  const said: string[] = [];
+  const log = console.log;
+  console.log = (...a: unknown[]) => said.push(a.join(" "));
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: pg, credential, moduleEntrypoints: [fixture("store-seat-unclaimed.mjs")] });
+    console.log = log;
+    assert.ok(said.some((s) => /registers tools under "mesh-store".*not served/.test(s)), said.join("\n"));
+    assert.deepEqual((await callTool(asker, "postgres.databases", {})).result, { software: "postgres" });
+    await assert.rejects(callTool(asker, "seat:mesh-store.databases", {}), /no responders|503/i);
+  } finally {
+    console.log = log;
+    stop();
+    await asker.close();
+    await pg.close();
+    await stream.close();
+  }
+});

node-tools/test/node-runtime.test.ts

@@ -0,0 +1,234 @@
+/**
+ * One runtime per node serves every assigned module's tools (novox/hq ADR 0175, to-be 38 WP1). The
+ * node's runtime is handed a list of modules and their bundles on the node's credential; it reads
+ * one membership per module, serves each module's tools on that module's subjects and each held
+ * seat's verbs on the seat's, names a bundle that fails to load without dropping the others, and
+ * re-serves a module whose membership is re-issued mid-run. Against a real bus with JetStream.
+ *
+ *   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/node-runtime.test.ts
+ */
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { fileURLToPath } from "node:url";
+import { cpSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from "node:fs";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { connect, StringCodec } from "nats";
+
+import { resetTools } from "@novox/mesh-sdk/tools";
+
+import { connectNats, membershipSubject } from "../dist/broker-nats.js";
+import { callTool, toolsOn } from "../dist/client.js";
+import { servedModulesFrom } from "../dist/main.js";
+import { runTools } from "../dist/runtime.js";
+
+const url = process.env.MESH_TEST_NATS;
+const fixture = (name: string) => fileURLToPath(new URL(`./fixtures/${name}`, import.meta.url));
+const sc = StringCodec();
+
+/** The controller's job, done by hand: the ASSIGNMENTS stream (last-per-subject, direct get) and an
+ *  EVENTS stream for what a tool emits. */
+async function aMesh() {
+  const nc = await connect({ servers: url! });
+  const jsm = await nc.jetstreamManager();
+  for (const name of ["ASSIGNMENTS", "EVENTS"]) {
+    try {
+      await jsm.streams.delete(name);
+    } catch {
+      // none yet
+    }
+  }
+  await jsm.streams.add({ name: "ASSIGNMENTS", subjects: ["mesh.assignment.>"], max_msgs_per_subject: 1, allow_direct: true } as never);
+  await jsm.streams.add({ name: "EVENTS", subjects: ["mesh.mod.*.event.>"] });
+  return {
+    async issue(m: object & { node: string; module: string }) {
+      await nc.jetstream().publish(membershipSubject(m.node, m.module), sc.encode(JSON.stringify(m)));
+    },
+    /** The next subject an event lands on, under a pattern. */
+    nextEvent(pattern: string): Promise<string> {
+      const sub = nc.subscribe(pattern, { max: 1 });
+      return (async () => {
+        for await (const m of sub) return m.subject;
+        throw new Error("no event");
+      })();
+    },
+    async close() {
+      await nc.close();
+    },
+  };
+}
+
+/** A membership as the controller issues one on a machine, with the module's own subject when it
+ *  answers for the module anywhere, and the verbs of the node seats it holds. */
+function membershipOf(module: string, node: string, opts: { plain?: boolean; seats?: Record<string, string[]> } = {}) {
+  const own = `mesh.mod.${module}`;
+  const serves: { subject: string; queue?: string }[] = [{ subject: `${own}.tool.{tool}.${node}` }];
+  if (opts.plain) serves.push({ subject: `${own}.tool.{tool}`, queue: `serve.${module}` });
+  const seats = Object.entries(opts.seats ?? {}).flatMap(([seat, verbs]) =>
+    verbs.map((verb) => ({ seat, verb, subject: `mesh.seat.${seat}.tool.${verb}.${node}` })));
+  return { node, module, serves, seats, emits: `${own}.event.{event}`, tools: `${own}.tool.tools` };
+}
+
+/** Wait for something to be served: the bus answers "no responders" at once until it is. */
+async function until<T>(attempt: () => Promise<T>, tries = 50): Promise<T> {
+  for (let i = 0; ; i++) {
+    try {
+      return await attempt();
+    } catch (e) {
+      if (i >= tries) throw e;
+      await new Promise((r) => setTimeout(r, 100));
+    }
+  }
+}
+
+test("MESH_TOOL_MODULES names modules and their entrypoints; a bare path is the credential's own module's", () => {
+  const have = servedModulesFrom(" alpha=/a/tools/index.js, beta=/b/one.js ,beta=/b/two.js, /mine/index.js ,node-tools=/own/x.js", "node-tools");
+  assert.deepEqual(have.serves, [
+    { module: "alpha", entrypoints: ["/a/tools/index.js"] },
+    { module: "beta", entrypoints: ["/b/one.js", "/b/two.js"] },
+  ]);
+  // The credential's own module, named or bare, is the one-module form either way.
+  assert.deepEqual(have.moduleEntrypoints, ["/mine/index.js", "/own/x.js"]);
+  assert.throws(() => servedModulesFrom("=/nothing.js", undefined), /neither <module>=<entrypoint>/);
+  assert.deepEqual(servedModulesFrom("", "x"), { serves: [], moduleEntrypoints: [] });
+});
+
+test("the node's runtime serves five modules' bundles on one credential — two of them launched, one broken — and follows a re-issued membership", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const mesh = await aMesh();
+  // Three modules assigned to the machine: alpha answers for itself anywhere, beta only here and
+  // holds the node-shelf seat, gamma's bundle is broken.
+  await mesh.issue(membershipOf("alpha", "anchor", { plain: true }));
+  await mesh.issue(membershipOf("beta", "anchor", { seats: { "node-shelf": ["list", "clear"] } }));
+  await mesh.issue(membershipOf("gamma", "anchor"));
+  // Two more, launched rather than loaded (ADR 0188): delta is Python and holds the node-lamp seat;
+  // epsilon is TypeScript written against the protocol and marked executable.
+  await mesh.issue(membershipOf("delta", "anchor", { seats: { "node-lamp": ["on"] } }));
+  await mesh.issue(membershipOf("epsilon", "anchor"));
+  // The node's credential: the runtime module's name, no claims (seats come from the memberships).
+  const credential = { url, node: "anchor", module: "node-tools" };
+  const nodeTools = await connectNats(credential);
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  const said: string[] = [];
+  const log = console.log;
+  console.log = (...a: unknown[]) => said.push(a.join(" "));
+  let stop = () => {};
+  try {
+    process.env.MESH_OPERATOR_ACCOUNT = "somebody";
+    process.env.MESH_OPERATOR_HOME = "/home/somebody";
+    stop = await runTools({
+      broker: nodeTools,
+      credential,
+      serves: [
+        { module: "alpha", entrypoints: [fixture("many-alpha.mjs")] },
+        { module: "beta", entrypoints: [fixture("many-beta.mjs")] },
+        { module: "gamma", entrypoints: [fixture("many-broken.mjs")] },
+        { module: "delta", entrypoints: [fixture("many-delta.py")] },
+        { module: "epsilon", entrypoints: [fixture("many-epsilon.mjs")] },
+      ],
+    });
+    console.log = log;
+    assert.deepEqual(nodeTools.serving().sort(), ["alpha", "beta", "delta", "epsilon", "gamma", "node-tools"]);
+    assert.ok(said.some((s) => /the operator's account here is somebody \(home \/home\/somebody\)/.test(s)), said.join("\n"));
+    assert.ok(said.some((s) => /gamma's bundle .*many-broken\.mjs failed to load: gamma's bundle cannot find its client; its tools are not served here/.test(s)), said.join("\n"));
+    assert.ok(said.some((s) => /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/.test(s)), said.join("\n"));
+
+    // Five tools answer, each where its module's membership says: alpha anywhere and here, beta here only.
+    assert.deepEqual((await callTool(asker, "alpha.one", {})).result, { alpha: 1 });
+    assert.deepEqual((await callTool(asker, "alpha.one@anchor", {})).result, { alpha: 1 });
+    assert.deepEqual((await callTool(asker, "beta.three@anchor", {})).result, { beta: 3 });
+    assert.deepEqual((await callTool(asker, "beta.four@anchor", {})).result, { beta: 4 });
+    assert.deepEqual((await callTool(asker, "beta.five@anchor", {})).result, { beta: 5 });
+    await assert.rejects(callTool(asker, "beta.three", {}), /no responders|503/i, "beta was not issued the module's plain subject");
+
+    // Two seat verbs answer on the seat's subjects, held by beta.
+    assert.deepEqual((await callTool(asker, "seat:node-shelf.list@anchor", {})).result, { shelf: ["a", "b"] });
+    assert.deepEqual((await callTool(asker, "seat:node-shelf.clear@anchor", {})).result, { cleared: true });
+
+    // A bundle in another language answers the same way, its seat verb among them; so does a
+    // TypeScript bundle served through the protocol rather than imported.
+    assert.deepEqual((await callTool(asker, "delta.greet@anchor", { who: "mesh" })).result, { greeting: "hello mesh", language: "python" });
+    assert.deepEqual((await callTool(asker, "seat:node-lamp.on@anchor", {})).result, { on: true, language: "python" });
+    assert.deepEqual((await callTool(asker, "epsilon.seven@anchor", {})).result, { epsilon: 7, via: "stdio" });
+    // A child that exits mid-call tells the caller so and is started again on the next call.
+    await assert.rejects(callTool(asker, "delta.die@anchor", {}), /delta's bundle exited \(3\)/);
+    assert.deepEqual((await callTool(asker, "delta.greet@anchor", {})).result, { greeting: "hello world", language: "python" });
+
+    // A tool that emits does so as its module, not as the runtime.
+    const landed = mesh.nextEvent("mesh.mod.*.event.>");
+    assert.deepEqual((await callTool(asker, "alpha.two", {})).result, { alpha: 2 });
+    assert.equal(await landed, "mesh.mod.alpha.event.happened");
+
+    // `tools` answers for each: what alpha and beta serve, and why gamma serves nothing.
+    const gamma = await asker.request<Record<string, never>, { module: string; tools: unknown[]; failed?: string }>("gamma.tools@anchor", {});
+    assert.deepEqual(gamma, { module: "gamma", tools: [], failed: "gamma's bundle cannot find its client" });
+    const beta = await asker.request<Record<string, never>, { tools: { name: string; subjects?: string[] }[] }>("beta.tools@anchor", {});
+    assert.deepEqual(beta.tools.map((x) => x.name), ["three", "four", "five"]);
+    assert.deepEqual(beta.tools[0]!.subjects, ["mesh.mod.beta.tool.three.anchor"]);
+
+    // And discovery says so, with the reason, beside the modules that answered.
+    const catalogue = await connectNats({ url, module: "mesh-catalog" });
+    await catalogue.handle("catalog_modules", async () => ({ modules: [{ module: "alpha" }, { module: "beta" }, { module: "gamma" }, { module: "delta" }, { module: "epsilon" }] }));
+    try {
+      const have = await toolsOn(asker);
+      assert.deepEqual(have.tools.map((x) => `${x.module}.${x.name}`), ["alpha.one", "alpha.two", "beta.five", "beta.four", "beta.three", "delta.die", "delta.greet", "epsilon.seven"]);
+      assert.deepEqual(have.notAnswering, ["gamma (its tools bundle failed to load: gamma's bundle cannot find its client)", "mesh-controller (seat)"]);
+    } finally {
+      await catalogue.close();
+    }
+
+    // The mesh re-issues beta's membership mid-run — now answering for the module anywhere — and
+    // the runtime serves the new subject without a restart.
+    await mesh.issue(membershipOf("beta", "anchor", { plain: true, seats: { "node-shelf": ["list", "clear"] } }));
+    assert.deepEqual((await until(() => callTool(asker, "beta.three", {}))).result, { beta: 3 });
+    assert.deepEqual((await callTool(asker, "seat:node-shelf.list@anchor", {})).result, { shelf: ["a", "b"] });
+  } finally {
+    console.log = log;
+    delete process.env.MESH_OPERATOR_ACCOUNT;
+    delete process.env.MESH_OPERATOR_HOME;
+    stop();
+    await asker.close();
+    await nodeTools.close();
+    await mesh.close();
+    resetTools();
+  }
+});
+
+test("a bundle carrying its own copy of the SDK registers into the runtime's registry, and its tools are served (issue 209)", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  // A bundle as the toolchain packs one: its compiled entrypoint, a package.json saying ES modules,
+  // and its dependencies copied in — the SDK among them, a second copy beside the runtime's own.
+  const dir = mkdtempSync(join(tmpdir(), "mesh-bundle-"));
+  const sdk = realpathSync(fileURLToPath(new URL("../node_modules/@novox/mesh-sdk/", import.meta.url)));
+  cpSync(sdk, join(dir, "node_modules", "@novox", "mesh-sdk"), { recursive: true });
+  writeFileSync(join(dir, "package.json"), '{"type":"module","private":true}\n');
+  writeFileSync(join(dir, "index.js"),
+    'import { registerModuleTools } from "@novox/mesh-sdk/tools";\n' +
+    'registerModuleTools("zeta", () => [{ name: "probe", description: "answers", input: {}, run: async () => ({ zeta: true }) }]);\n');
+  const mesh = await aMesh();
+  await mesh.issue(membershipOf("zeta", "anchor"));
+  const credential = { url, node: "anchor", module: "node-tools" };
+  const nodeTools = await connectNats(credential);
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  const said: string[] = [];
+  const log = console.log;
+  console.log = (...a: unknown[]) => said.push(a.join(" "));
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: nodeTools, credential, serves: [{ module: "zeta", entrypoints: [join(dir, "index.js")] }] });
+    console.log = log;
+    assert.ok(said.some((s) => /serving 1 tool\(s\) for 1 module\(s\): zeta\.probe/.test(s)), said.join("\n"));
+    assert.deepEqual((await callTool(asker, "zeta.probe@anchor", {})).result, { zeta: true });
+  } finally {
+    console.log = log;
+    stop();
+    await asker.close();
+    await nodeTools.close();
+    await mesh.close();
+    rmSync(dir, { recursive: true, force: true });
+    resetTools();
+  }
+});

node-tools/test/node-tools-serve.test.ts

@@ -0,0 +1,63 @@
+/**
+ * The runtime as the node-tools module (novox/hq ADR 0175 §6, to-be 38 WP3): started the way the
+ * host starts it — `main.js` with the node's credential and MESH_TOOL_MODULES — it serves the bundles
+ * AND answers MCP on loopback as the console, through which a tool it serves can be called.
+ *
+ *   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/node-tools-serve.test.ts
+ */
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { spawn, type ChildProcess } from "node:child_process";
+import { mkdtemp, writeFile } from "node:fs/promises";
+import { join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { connectNats } from "../dist/broker-nats.js";
+
+const url = process.env.MESH_TEST_NATS;
+const fixture = (name: string) => fileURLToPath(new URL(`./fixtures/${name}`, import.meta.url));
+
+async function post(endpoint: string, body: unknown): Promise<any> {
+  const res = await fetch(endpoint, { method: "POST", headers: { "content-type": "application/json" }, body: JSON.stringify(body) });
+  return res.json();
+}
+
+test("as node-tools, serve loads the bundles and is the console on loopback", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  // The catalogue, for discovery; the node credential names the runtime module and no claims.
+  const catalogue = await connectNats({ url, module: "mesh-catalog" });
+  await catalogue.handle("catalog_modules", async () => ({ modules: [{ module: "alpha" }] }));
+  t.after(() => catalogue.close());
+  const dir = await mkdtemp("/tmp/node-tools-");
+  const credential = join(dir, "broker");
+  await writeFile(credential, JSON.stringify({ url, node: "desk", module: "node-tools", user: "desk.node-tools", password: "x" }));
+  const child: ChildProcess = spawn(process.execPath, ["dist/main.js"], {
+    env: {
+      ...process.env,
+      MESH_BROKER_FILE: credential,
+      MESH_TOOL_MODULES: `alpha=${fixture("many-alpha.mjs")}`,
+      MESH_CONSOLE_LISTEN: "127.0.0.1:0",
+    },
+    stdio: ["ignore", "pipe", "pipe"],
+  });
+  t.after(() => {
+    child.kill("SIGTERM");
+  });
+  const endpoint = await new Promise<string>((resolve, reject) => {
+    let out = "";
+    let err = "";
+    child.stdout!.on("data", (d) => {
+      out += d.toString();
+      const m = /listening on (http:\/\/[^/]+\/mcp) as desk\.node-tools/.exec(out);
+      if (m) resolve(m[1]!);
+    });
+    child.stderr!.on("data", (d) => (err += d.toString()));
+    child.on("exit", (code) => reject(new Error(`serve exited ${code}: ${err}`)));
+  });
+  const listed = await post(endpoint, { jsonrpc: "2.0", id: 1, method: "tools/list" });
+  assert.deepEqual(listed.result.tools.map((x: any) => x.name).filter((n: string) => n.startsWith("alpha.")), ["alpha.one", "alpha.two"]);
+  // A tool the same process serves on the bus, called through the console it also is.
+  const called = await post(endpoint, { jsonrpc: "2.0", id: 2, method: "tools/call", params: { name: "alpha.one", arguments: { node: "desk" } } });
+  assert.deepEqual(JSON.parse(called.result.content[0].text), { alpha: 1 });
+});

node-tools/test/runtime-tools.test.ts

@@ -0,0 +1,60 @@
+/**
+ * Every module's runtime answers `tools` for it (novox/hq ADR 0152, design 34 §3): the names,
+ * descriptions and schemas from the code that answers them. Against a real bus, because the claim is
+ * what a second connection gets back.
+ *
+ *   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/runtime-tools.test.ts
+ */
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { fileURLToPath } from "node:url";
+
+import { resetTools } from "@novox/mesh-sdk/tools";
+
+import { connectNats } 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));
+
+test("a module registering two tools answers three names, the third being what it serves", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const shop = await connectNats({ url, node: "one", module: "shop" });
+  const asker = await connectNats({ url, module: "person.ada" });
+  const stop = await runTools({ broker: shop, moduleEntrypoints: [fixture("shop-tools.mjs")] });
+  try {
+    const answer = await asker.request<Record<string, never>, { module: string; tools: { name: string; input: unknown }[] }>(
+      "shop.tools",
+      {},
+    );
+    assert.equal(answer.module, "shop");
+    assert.deepEqual(answer.tools.map((x) => x.name), ["price", "refund"]);
+    // The schema travels with the name: a name alone is not callable by something that has never
+    // seen the mesh before.
+    assert.deepEqual(answer.tools[0].input, { of: { type: "string", description: "the thing" } });
+    // And the tools themselves still answer beside it.
+    const priced = await asker.request<{ of: string }, { cost: number }>("shop.price", { of: "a hat" });
+    assert.equal(priced.cost, 12);
+  } finally {
+    stop();
+    await asker.close();
+    await shop.close();
+  }
+});
+
+test("a module naming a tool of its own `tools` is refused at load", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const clash = await connectNats({ url, node: "one", module: "clash" });
+  try {
+    await assert.rejects(
+      () => runTools({ broker: clash, moduleEntrypoints: [fixture("clash-tools.mjs")] }),
+      /names a tool "tools"/,
+    );
+  } finally {
+    resetTools();
+    await clash.close();
+  }
+});

src/client.ts

@@ -1,125 +0,0 @@
-/**
- * A person's client: the mesh's tools from a workstation (novox/hq design 25 §7).
- *
- * 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: a
- * person connects as their own bus user, publishes on the tool subjects their account permits, and the
- * server refuses anything else. So "what may this person do" 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 a person may NOT do is the more interesting half, and none of it is enforced here — it is the
- * account (design 25 §4): they cannot publish an event, so they cannot claim a module said something;
- * they have no consumer, so there is no delivery to acknowledge; and they cannot answer a request, so
- * they 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 Credential } from "./broker-nats.js";
-
-/** Where the catalogue answers what tools the mesh has. */
-const CATALOGUE_TOOLS = "mesh-catalog.catalog_tools";
-
-/** A tool as the catalogue describes one. */
-export interface Tool {
-  module: string;
-  name: string;
-  description?: string;
-  /** The JSON schema of what it takes, as the module declared it. */
-  input?: unknown;
-}
-
-/**
- * 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 });
-}
-
-/**
- * What tools the mesh has, asked of the catalogue.
- *
- * **Asked, not configured.** The catalogue is the only thing that knows what is installed, and a
- * client carrying its own list would be a list that goes stale the first time a module is assigned —
- * silently, because a tool that is not offered looks exactly like a tool that does not exist.
- */
-export async function toolsOn(bus: Broker): Promise<Tool[]> {
-  const answered = await bus.request<Record<string, never>, { tools?: Tool[] } | Tool[]>(
-    CATALOGUE_TOOLS,
-    {},
-  );
-  const tools = Array.isArray(answered) ? answered : (answered.tools ?? []);
-  return tools
-    .slice()
-    .sort((a: Tool, b: Tool) => `${a.module}.${a.name}`.localeCompare(`${b.module}.${b.name}`));
-}
-
-/** Call one tool. The key is `<module>.<tool>`, which is what a person types and what their account
- *  permits — one vocabulary, so a refusal names the thing they asked for. */
-export async function callTool(bus: Broker, key: string, args: unknown): Promise<unknown> {
-  if (!key.includes(".")) {
-    throw new Error(
-      `"${key}" does not name a tool: write <module>.<tool>, as \`mesh tools\` lists them`,
-    );
-  }
-  return bus.request<unknown, unknown>(key, args ?? {});
-}
-
-/**
- * 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 person, 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 — ` +
-      "`mesh tools` lists what the catalogue says is there.";
-  }
-  if (/permissions violation|authorization/i.test(message)) {
-    return `this credential may not call ${key}. What it may call was fixed when it was issued; ` +
-      "`operator issue` again with the tool named, or ask somebody who can.";
-  }
-  if (/timeout/i.test(message)) {
-    return `${key} did not answer in time. Something is serving it, so this is the tool being slow ` +
-      "rather than absent.";
-  }
-  return `${key} failed: ${message}`;
-}

src/mcp.ts

@@ -1,139 +0,0 @@
-/**
- * The mesh's tools as an MCP server, over stdio (novox/hq design 25 §7).
- *
- * **A thin adapter and nothing more.** Every tool an agent sees is one the catalogue listed and one
- * this credential 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 manifest 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 workstation.
- */
-import type { Broker } from "@novox/mesh-sdk/messaging";
-
-import { callTool, toolsOn, whyItFailed, type Tool } 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. */
-const PROTOCOL = "2024-11-05";
-
-interface Request {
-  jsonrpc: string;
-  id?: number | string | null;
-  method: string;
-  params?: Record<string, unknown>;
-}
-
-/**
- * Serve until stdin closes, which is how a host ends a session.
- *
- * The tool list is fetched once, on the first `tools/list`, and kept. An agent asks for it repeatedly
- * and the catalogue's answer does not change mid-session; refetching would make every turn cost a
- * round trip to a module for something nobody changed.
- */
-export async function serveMcp(bus: Broker, who: string): Promise<void> {
-  let known: Tool[] | undefined;
-
-  const say = (message: unknown) => {
-    process.stdout.write(`${JSON.stringify(message)}\n`);
-  };
-  const answer = (id: Request["id"], result: unknown) => say({ jsonrpc: "2.0", id, result });
-  const refuse = (id: Request["id"], code: number, message: string) =>
-    say({ jsonrpc: "2.0", id, error: { code, message } });
-
-  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;
-    }
-    // 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":
-        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 ${who}. Every call goes to the module ` +
-            `that serves it; what may be called was fixed when this credential was issued, so a ` +
-            `refusal means the credential, not the tool.`,
-        });
-        break;
-
-      case "notifications/initialized":
-        break;
-
-      case "tools/list": {
-        try {
-          known ??= await toolsOn(bus);
-        } catch (e) {
-          refuse(request.id, -32603, whyItFailed("mesh-catalog.catalog_tools", e));
-          break;
-        }
-        answer(request.id, {
-          tools: known.map((t) => ({
-            name: `${t.module}.${t.name}`,
-            description: t.description ?? `${t.name}, served by ${t.module}`,
-            // The module's own schema, passed through. An empty object is a tool that takes nothing,
-            // which is a real answer and not a missing one.
-            inputSchema: t.input ?? { type: "object", properties: {} },
-          })),
-        });
-        break;
-      }
-
-      case "tools/call": {
-        const name = String(request.params?.name ?? "");
-        const args = request.params?.arguments ?? {};
-        try {
-          const result = await callTool(bus, name, args);
-          // 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.
-          answer(request.id, {
-            content: [{ type: "text", text: JSON.stringify(result, null, 2) }],
-          });
-        } 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.
-          answer(request.id, {
-            content: [{ type: "text", text: whyItFailed(name, e) }],
-            isError: true,
-          });
-        }
-        break;
-      }
-
-      default:
-        if (!notification) {
-          refuse(request.id, -32601, `mesh's MCP surface has no ${request.method}`);
-        }
-    }
-  }
-}
-
-/** 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();
-}

src/mesh.ts

@@ -1,145 +0,0 @@
-#!/usr/bin/env node
-/**
- * `mesh` — the mesh's tools from a workstation, for a person (novox/hq design 25 §7).
- *
- * Three verbs and nothing else. What tools are there, call one, and serve the same two to an agent
- * over MCP. 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 this credential may call
- *     mesh call <module>.<tool> [json]  call one, arguments as JSON on the command line or on stdin
- *     mesh mcp                          the same, as an MCP server over stdio
- *
- * The credential comes from MESH_CREDENTIAL, or --credential. It is the JSON `operator issue` printed.
- */
-import { readFile } from "node:fs/promises";
-
-import { callTool, connectAs, credentialFrom, toolsOn, whyItFailed, type Tool } from "./client.js";
-import { serveMcp } from "./mcp.js";
-
-const usage = `mesh tools
-mesh call <module>.<tool> [json]
-mesh mcp
-
-  --credential <file>   the JSON \`operator issue\` printed; default $MESH_CREDENTIAL`;
-
-async function main(argv: string[]): Promise<number> {
-  const args = [...argv];
-  let credentialPath = process.env.MESH_CREDENTIAL ?? "";
-  for (let i = 0; i < args.length; i++) {
-    if (args[i] === "--credential") {
-      credentialPath = args[i + 1] ?? "";
-      args.splice(i, 2);
-      i--;
-    }
-  }
-  const verb = args.shift();
-  if (!verb || verb === "help" || verb === "--help") {
-    console.log(usage);
-    return verb ? 0 : 1;
-  }
-  if (!credentialPath) {
-    console.error(
-      "no credential: set MESH_CREDENTIAL or pass --credential <file>. It is the JSON " +
-        "`operator issue` printed, saved verbatim.",
-    );
-    return 1;
-  }
-
-  const held = await credentialFrom(credentialPath);
-  const bus = await connectAs(held);
-  try {
-    switch (verb) {
-      case "tools":
-        return await listing(bus, held.person);
-      case "call":
-        return await calling(bus, args);
-      case "mcp":
-        // Serves until stdin closes, which is how an MCP host ends a session.
-        await serveMcp(bus, held.person ?? held.user ?? "somebody");
-        return 0;
-      default:
-        console.error(`mesh has no "${verb}".\n\n${usage}`);
-        return 1;
-    }
-  } finally {
-    await bus.close();
-  }
-}
-
-async function listing(bus: Awaited<ReturnType<typeof connectAs>>, who?: string): Promise<number> {
-  let tools: Tool[];
-  try {
-    tools = await toolsOn(bus);
-  } catch (e) {
-    console.error(whyItFailed("mesh-catalog.catalog_tools", e));
-    return 1;
-  }
-  if (tools.length === 0) {
-    console.log("the catalogue lists no tools; nothing on this mesh serves any");
-    return 0;
-  }
-  // **What the catalogue has, not what this credential may call.** The two differ and the difference
-  // is the point: a person seeing only their own tools cannot tell "not installed" from "not yours",
-  // and those need different people to fix them.
-  for (const t of tools) {
-    const name = `${t.module}.${t.name}`;
-    console.log(t.description ? `${name.padEnd(36)} ${t.description}` : name);
-  }
-  if (who) {
-    console.log(`\nthis is what the mesh has. What ${who} may call was fixed when the credential was issued.`);
-  }
-  return 0;
-}
-
-async function calling(
-  bus: Awaited<ReturnType<typeof connectAs>>,
-  args: string[],
-): Promise<number> {
-  const key = args.shift();
-  if (!key) {
-    console.error("mesh call <module>.<tool> [json]");
-    return 1;
-  }
-  const raw = args.length > 0 ? args.join(" ") : await maybeStdin();
-  let parsed: unknown = {};
-  if (raw.trim() !== "") {
-    try {
-      parsed = JSON.parse(raw);
-    } catch (e) {
-      console.error(`the arguments are not JSON: ${(e as Error).message}`);
-      return 1;
-    }
-  }
-  try {
-    const answer = await callTool(bus, key, parsed);
-    console.log(JSON.stringify(answer, null, 2));
-    return 0;
-  } catch (e) {
-    console.error(whyItFailed(key, e));
-    return 1;
-  }
-}
-
-/** Arguments on stdin, for a call whose JSON is too long or too quoted to type. Empty when stdin is a
- *  terminal, so `mesh call x.y` with no arguments does not hang waiting for something nobody is
- *  typing. */
-async function maybeStdin(): Promise<string> {
-  if (process.stdin.isTTY) return "";
-  const chunks: Buffer[] = [];
-  for await (const chunk of process.stdin) chunks.push(chunk as Buffer);
-  return Buffer.concat(chunks).toString("utf8");
-}
-
-// Only when run, so a test can import the pieces.
-if (process.argv[1] && import.meta.url === new URL(`file://${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;

src/runtime.ts

@@ -1,35 +0,0 @@
-// The tool runtime — the thin per-node process that makes a module's tools actually serve. It
-// binds the mesh broker, loads the assigned modules' tool entrypoints (each of which calls
-// registerModuleTools as it imports), and hands them to the sdk's serving harness. Everything hard
-// — dispatch, collection, duplicate-name safety — is the sdk's; this is the wrapper.
-
-import { pathToFileURL } from "node:url";
-import { resolve } from "node:path";
-import { useBroker } from "@novox/mesh-sdk/messaging";
-import { serveTools, listTools } from "@novox/mesh-sdk/tools";
-import type { Broker } from "@novox/mesh-sdk/messaging";
-
-export interface RuntimeOptions {
-  /** The mesh broker to serve over. */
-  broker: Broker;
-  /** Absolute paths to the assigned modules' compiled tool entrypoints (e.g. .../umami/tools/index.js). */
-  moduleEntrypoints: string[];
-}
-
-/** 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);
-
-  for (const entry of opts.moduleEntrypoints) {
-    // Importing the entrypoint runs its registerModuleTools(...) — that is the whole handshake.
-    await import(pathToFileURL(resolve(entry)).href);
-  }
-
-  // Serve the RPC endpoint only if a module actually registered a tool. A pure-events module (the
-  // audit logger) registers none, and its scoped account may not declare the serve queue — so a
-  // runtime that always served would fail for exactly the modules that never needed it.
-  const tools = listTools();
-  const stop = tools.length > 0 ? await serveTools(opts.broker) : () => {};
-  console.log(`[mesh-tools] serving ${tools.length} tool(s): ${tools.map((t) => t.name).join(", ") || "(none)"}`);
-  return stop;
-}

test/client.test.ts

@@ -1,105 +0,0 @@
-/**
- * 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, toolsOn, whyItFailed } from "../dist/client.js";
-
-const url = process.env.MESH_TEST_NATS;
-
-/** A module serving the catalogue's tool list and one tool of its own, so the client has a mesh to
- *  talk to. 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_tools", async () => ({
-    tools: [
-      { module: "shop", name: "price", description: "what something costs", input: { type: "object" } },
-      { module: "mesh-catalog", name: "catalog_tools", description: "what tools the mesh has" },
-    ],
-  }));
-  await shop.handle("price", async (body: { of?: string }) => ({ of: body.of ?? "nothing", cost: 12 }));
-  return {
-    async close() {
-      await catalogue.close();
-      await shop.close();
-    },
-  };
-}
-
-test("a person sees what the catalogue says the mesh has, sorted", 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 tools = await toolsOn(person);
-    assert.deepEqual(
-      tools.map((x) => `${x.module}.${x.name}`),
-      ["mesh-catalog.catalog_tools", "shop.price"],
-      "the list is what the catalogue answered, in a stable order",
-    );
-  } 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, { 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/);
-});