ADR 0193: every bundle the runtime serves is launched, and the runtime knows no language; design 38 WP4d

2026-10-03 21:05:03 +02:00
parent 6a1fc71a4c
commit 6d53f9168a
5 changed files with 113 additions and 0 deletions
@@ -87,6 +87,10 @@ that lets one bundle in that language be built, delivered and answer one tool on
 Anything beyond that is added when a module needs it. A skeleton that is not proven by one bundle
 answering is not a skeleton; it is a promise.

+> **The mechanism changed — 2026-10-03, by ADR 0193.** §2's allowance that a TypeScript bundle may
+> be imported into the runtime's own process is withdrawn: every served bundle is launched, and the
+> build makes each served entrypoint executable. The rest of §2 stands.
+
 ## Consequences

 - The runtime gains a launcher beside its loader. The loader, the memberships, the seats and the
@@ -88,6 +88,10 @@ tools answering from the runtime, and the registration gate of
 [to-be 38](../03-DESIGN/01-to-be/38-building-the-operators-machine.md) WP2 then refuses the
 container shape for every module, as ADR 0188 already provides.

+> **The mechanism changed — 2026-10-03, by ADR 0193.** Decision 3's imported path — the environment
+> handed to an imported bundle's contributor — has nothing left to do: every served bundle is
+> launched, and a launched bundle's environment is its own. The decision stands.
+
 ## Consequences

 - The manifest gains one field on one artifact kind; the composer gains one more thing to resolve
@@ -0,0 +1,88 @@
+---
+topic: what runs on it
+status: accepted
+date: 2026-10-03
+deciders: jochen
+reconstructed: false
+extends: 02-DECISIONS/0188-a-modules-own-code-is-bundles-in-any-language-and-a-tools-bundle-speaks-mcp-to-the-runtime.md
+---
+
+# 193. Every bundle the runtime serves is launched, and the runtime knows no language
+
+## Context
+
+[ADR 0188](0188-a-modules-own-code-is-bundles-in-any-language-and-a-tools-bundle-speaks-mcp-to-the-runtime.md)
+§2 made a served bundle a process that speaks MCP over stdio, and kept one exception: a TypeScript
+bundle may be imported into the runtime's own process, "a shortcut over the same contract". Every
+module's tools today take the shortcut, and it is where the day's defects came from:
+
+- [Issue 209](../04-ISSUES/209-a-bundles-own-sdk-copy-registers-into-a-registry-the-runtime-never-reads/00-report.md):
+  an imported bundle's own copy of the SDK registered into a registry the runtime never read; fixed
+  by a resolve hook that redirects every bundle's SDK import to the runtime's copy.
+- [ADR 0192](0192-a-tools-bundle-declares-what-it-is-given-and-the-runtime-hands-it-to-that-bundle-alone.md):
+  thirty modules' environments in one process had to be kept apart by an SDK change and runtime
+  bookkeeping, where a process of its own has an environment of its own by construction.
+- One faulty module can block or crash every other module's tools on its node.
+
+And the shortcut ties the runtime to Node.js: only a JavaScript runtime can import JavaScript. The
+operator's direction on 2026-10-03: *a module's tools are written in any language and the builder
+builds them; the runtime runs them all and announces them; it should be fully language agnostic,
+and node-tools can be rewritten in Go.*
+
+## Considered Options
+
+1. **Keep the shortcut.** Rejected: it is the cause of the three defects above, and it pins the
+   runtime's language.
+2. **Launch every served bundle; the runtime knows how to start each language** (`node` for a
+   `.js`, exec for a binary). Rejected: the runtime would hold a table of interpreters, and a
+   runtime in Go would carry Node.js's knowledge for nothing.
+3. **Launch every served bundle, and the build makes each served entrypoint executable.** Chosen.
+   A compiled language's binary is executable already; for an interpreted one the toolchain writes
+   a launcher beside the entrypoint — for TypeScript, a file that imports the entrypoint and serves
+   what it registered over stdio, using the bundle's own SDK. The runtime execs what it is given.
+
+## Decision
+
+**1. Every bundle the node's runtime serves is a child process speaking MCP over stdio.** The
+in-process shortcut of ADR 0188 §2 is withdrawn. Everything else ADR 0188 §2 says — `tools/list`,
+`tools/call`, `<seat>.<verb>` naming a seat's verb, the runtime serving each on the bus — stands.
+
+**2. The runtime knows no language.** It is given an executable per served entrypoint and starts
+it, with that bundle's environment ([ADR 0192](0192-a-tools-bundle-declares-what-it-is-given-and-the-runtime-hands-it-to-that-bundle-alone.md))
+over its own words, and the module it serves it as. What makes an entrypoint executable is the
+toolchain's business: a binary is one; an interpreted language's toolchain writes a launcher.
+
+**3. A launched bundle is told the module it serves as**, so that what it lists unprefixed is that
+module's own tools and a seat's verbs are always `<seat>.<verb>`, whichever it registered first.
+
+**4. The runtime may be written in any language.** Nothing it does needs it to share a language
+with a bundle; the mesh's runtime moves to Go, against this contract, once the contract is proven
+in the runtime that exists.
+
+## Consequences
+
+- A process per served module per node. On the busiest machine that is a score of small children
+  where there was one process; a Go bundle costs a fraction of a Node.js one.
+- The SDK resolve hook (issue 209) and the per-registration environment hand-off (ADR 0192 §3,
+  imported bundles) have nothing left to do and go; a launched bundle's environment is its own.
+- A module's TypeScript tool code does not change: it registers as before, and the generated
+  launcher serves what it registered.
+- A bundle that crashes or hangs takes only its own tools down, and is started again on its next
+  call, as ADR 0188 already provides for a launched bundle.
+
+## How it is checked
+
+| Rule | Checked by |
+|---|---|
+| Every served bundle is launched | the runtime's tests: a TypeScript bundle and a bundle in a second language, both launched, both answering over a real bus; a non-executable entrypoint is refused by name |
+| The runtime knows no language | the runtime holds no interpreter: it execs the path it is given (code review; the Go runtime has no Node.js dependency at all) |
+| A TypeScript served entrypoint is executable | the builder's test: a TypeScript bundle's served entrypoint has a launcher beside it, mode 0755 |
+| A seat's verbs are named as the seat's whichever registers first | the SDK's test: a bundle registering its seat first and its own tools second lists `<seat>.<verb>` and its own tools unprefixed |
+| Live | the packet filter's and intrusion prevention's seat verbs and the moved tools answer from launched bundles on every machine |
+
+## References
+
+- [ADR 0175](0175-one-tool-runtime-per-node-serves-every-modules-tools-on-the-host-side.md),
+  [ADR 0188](0188-a-modules-own-code-is-bundles-in-any-language-and-a-tools-bundle-speaks-mcp-to-the-runtime.md),
+  [ADR 0192](0192-a-tools-bundle-declares-what-it-is-given-and-the-runtime-hands-it-to-that-bundle-alone.md)
+- [to-be 38](../03-DESIGN/01-to-be/38-building-the-operators-machine.md) WP4d
@@ -292,6 +292,7 @@ python3 00-META/checks/index.py            fail if stale
 - **0183** — [The Anthropic licence manager is a module holding a seat; it hands each node's agent its token over the bus, sealed; the controller and the host have no part](0183-the-anthropic-licence-manager-is-a-module-and-hands-tokens-to-the-agent-over-the-bus.md)
 - **0188** — [A module's own code is bundles in any language, and a tools bundle speaks MCP to the runtime](0188-a-modules-own-code-is-bundles-in-any-language-and-a-tools-bundle-speaks-mcp-to-the-runtime.md)
 - **0192** — [A tools bundle declares what it is given, and the runtime hands it to that bundle alone](0192-a-tools-bundle-declares-what-it-is-given-and-the-runtime-hands-it-to-that-bundle-alone.md)
+- **0193** — [Every bundle the runtime serves is launched, and the runtime knows no language](0193-every-bundle-the-runtime-serves-is-launched-and-the-runtime-knows-no-language.md)

 ### How it is built