Serve the API as an MCP server over streamable HTTP - #6
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`POST /api/mcp` exposes every operation in the generated OpenAPI document as an MCP tool, verbatim. The tool list is a pure function of the document, so a route that exists is a tool that exists and adding an endpoint needs no work in the bridge; `describeRoute`'s prose becomes the tool description and hono-openapi's derived `operationId` becomes the tool name. The one transformation is shape: MCP hands a tool a single flat `arguments` object while an HTTP operation splits its inputs across path, query and body, so `plan` flattens the three and `rebuild` puts them back. A name arriving in two places throws at startup rather than silently routing a value to the wrong slot. Notes on the design: - It lives on `app` beside `/api/openapi` and `/api/scalar`, not on `routes` — a protocol endpoint belongs in neither the document nor the RPC client's type. Carrying no `describeRoute` is also what stops it generating a tool for itself. - Dispatch is in-process via `app.request`, so the bridge never talks to its own HTTP port. A separate MCP process importing `@repo/api` would be a second PGlite opener, which corrupts the data dir silently. - Stateless: a fresh server and transport per POST, nothing to garbage-collect. A module-level transport registry is the hazard that already forced `db.ts` onto `globalThis`, since Vite re-evaluates on every edit. `enableJsonResponse` keeps replies plain JSON; GET returns 405. - Results are capped at 64 KB, because `getApiTypes` over the whole catalog is 8.6 MB and a response that evicts the conversation it was fetched for is worse than an error — it looks like success. - A failing route is `isError` in the result, never a thrown JSON-RPC error, so a caller can read the failure and correct itself. Only an unadvertised tool name is a protocol error. `@modelcontextprotocol/sdk` is `ssr.external` in the frontend and a direct dependency there, the same treatment PGlite gets and for the same reason: it is Node-targeted and pulls in express and ajv. Co-Authored-By: Claude <noreply@anthropic.com>
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POST /api/mcpexposes every operation in the generated OpenAPI document as an MCP tool, verbatim — the tool list is a pure function of the document, so a new route becomes a tool with no work in the bridge, withdescribeRoute's prose as the description and hono-openapi's derivedoperationIdas the name.The only transformation is shape: MCP passes a single flat
argumentsobject, soplanflattens each operation's path, query and body inputs into one schema andrebuildputs them back, throwing at startup if two differently-scoped names would collide.It is stateless (fresh server per POST,
enableJsonResponse, GET → 405) and dispatches in-process viaapp.request— a separate process importing@repo/apiwould be a second PGlite opener — with results capped at 64 KB becausegetApiTypesover the whole catalog is 8.6 MB, and a failing route surfaced asisErrorrather than a thrown JSON-RPC error so a caller can correct itself.Also adds
@modelcontextprotocol/sdkasssr.externalplus a direct frontend dependency (PGlite's treatment, for the same reason),src/mcp.test.tswhose central assertion is that every tool's advertised inputs equal its operation's declared inputs, and aCLAUDE.mdsection.🤖 Generated with Claude Code