git:20260714.5e9be0b to git:20260807.51556a5

# AGENTS.md for @webjsdev/mcp

The webjs **Model Context Protocol server** (extracted from `@webjsdev/cli` in

#415). A hand-rolled, READ-ONLY MCP stdio server, ZERO runtime dependency

beyond `@webjsdev/server` for its introspection data functions.

Framework-wide rules (workflow, JSDoc-in-`packages/`, no-build, commit

conventions) live in the **framework root [`../../AGENTS.md`](../../AGENTS.md)**

and apply here. Read that first. This file covers only what is specific to

`@webjsdev/mcp`.

## Entry points

- **`npx @webjsdev/mcp`** (`bin/webjs-mcp.js`): the agent-facing server an MCP

host registers. The scaffold wires it into `.claude.json`.

- **`webjs mcp`** (the CLI subcommand): delegates to `runMcpServer` from this

package, so the implementation has a single home. Back-compat only.

Both speak newline-delimited JSON-RPC 2.0 over stdio. STDOUT IS THE PROTOCOL

CHANNEL; every diagnostic goes to stderr. A malformed line is answered with a

parse error and never crashes the loop.

## Module map

```

bin/

webjs-mcp.js npx entry: reads the package version, runs runMcpServer

with the process streams.

src/

mcp.js runMcpServer({ stdin, stdout, stderr, cwd, version,

deps?, docsDeps?, sourceDeps? }). The JSON-RPC loop +

the tool/resource/prompt dispatch. Handshake:

initialize -> serverInfo + capabilities (tools +

resources + prompts); notifications/initialized -> no

reply; tools/list, tools/call, resources/*, prompts/*.

INTROSPECTION tools (read-only, appDir-scoped), each

projecting a @webjsdev/server function: list_routes

(buildRouteTable, via the shared projectRoutes from

routes-report.js), list_actions (buildActionIndex +

hashFile, now reports verb/cache/tags/invalidates per

#488 and excludes reserved config exports from the

callable-action list), list_components (scanComponents),

check (checkConventions via projectCheck). Export names

are extracted LEXICALLY (extractExportNames /

extractRouteMethods / extractActionConfig) so no app

module is loaded.

The `ui` tool (#983) is KIT-scoped, not appDir-scoped:

it projects the shared `@webjsdev/ui/registry/extract`

leaf (the kit inventory, or one component's helper

signatures + paste-ready @example + a11y header + deps),

the SAME leaf `webjsui view` renders. A drift test in

mcp.test.mjs asserts the tool output equals that leaf's

output.

`deps` / `docsDeps` / `sourceDeps` / `uiDeps` are

injectable for in-process tests.

mcp-docs.js KNOWLEDGE layer (#376): resolveDocsLocation (bundled

resources/ first, repo-root skill fallback in

dev), the init primer (sources the AGENTS.md

execution-model + invariants so it cannot drift), the

docs tool, resources (the skill references + SKILL.md + AGENTS.md

as webjs-docs://*), and the recipe PROMPTS.

mcp-source.js SOURCE tool (#378): reads the framework's own no-build

source from node_modules/@webjsdev/*/src (read-only,

traversal-guarded via realpath, loads no module).

resolveFrameworkRoots locates each package by probing

the require.resolve node_modules dirs.

check-report.js projectCheck(violations) -> { violations, summary }.

The shared shape returned by BOTH the MCP `check` tool

and `webjs check --json` (the CLI imports it from

`@webjsdev/mcp/check-report`), so the two are identical.

routes-report.js routePathFromDir(routeDir) + projectRoutes(table,

{ appDir, readFile, extractRouteMethods }) ->

{ pages, apis } (#975). The shared route projector

returned by BOTH the MCP `list_routes` tool and

`webjs routes --json` (the CLI imports it from

`@webjsdev/mcp/routes-report`), so the two are identical.

A leaf module: the two effectful deps are injected so it

needs no `mcp.js` import (no cycle). A drift test asserts

`list_routes` output equals `projectRoutes`.

scripts/

copy-mcp-resources.js prepack: bundle the repo-root skill (references + SKILL.md) + AGENTS.md

into resources/ (in `files`) so npx is self-contained.

Exports the reusable bundleDocs(...).

clean-mcp-resources.js postpack: remove the transient resources/ bundle so dev

always reads the live repo-root docs. Exports

cleanBundle(...).

```

## Invariants

1. **STDOUT is JSON-RPC only.** Never `console.log` in the request path;

diagnostics go to stderr (`logErr`). A stray stdout write corrupts the

stream.

2. **Read-only.** Every tool projects an existing `@webjsdev/server` data

function (or reads source/docs) and mutates nothing. No app module is loaded

(export names are extracted lexically) so there are no DB-init side effects.

3. **The docs bundle is transient.** `resources/` exists only inside the

published tarball (prepack writes it, postpack removes it). In the monorepo

it is absent and `resolveDocsLocation` falls back to the live repo-root docs,

so source stays single.

## Tests

`test/mcp.test.mjs`, `test/mcp-docs.test.mjs`, `test/mcp-source.test.mjs`,

`test/check-report.test.mjs`. `runMcpServer` is driven in-process with injected

deps, so no real server boots. Run `npm test` from the repo root.

---

Framework-wide rules and full API reference:

@../../AGENTS.md