fix(mcp): defer schema strip to lifespan (asyncio.run regression)#20
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v0.7.1 regressed by calling `_strip_internal_schema_fields()` at module import time via `asyncio.run()`. Stdio mode worked because the entry point hadn't started a loop yet, but Uvicorn imports the user app from inside `asyncio.run(self.serve(...))` so the same code path crashed with "asyncio.run() cannot be called from a running event loop" on every cluster pod. The mcp-server deployment in v0.13.1 of the monorepo restart-looped until rolled back. Fix: split `_strip_internal_schema_fields` into an async coroutine and call it from the right place per transport: - HTTP: wrap `mcp_app.lifespan` in a Starlette lifespan that awaits the strip before delegating to FastMCP's own lifespan. - Stdio: call `asyncio.run(_strip_internal_schema_fields())` inside `_run_stdio()` before `mcp.run()` boots its own loop. Pinned by `TestImportFromRunningLoopDoesNotCrash` which reloads the module from inside an async test and asserts `api_token` is gone after lifespan entry. Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
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Summary
v0.7.1 broke the cluster (
mono v0.13.1MCP Server deploy). Root cause:_strip_internal_schema_fields()calledasyncio.run()at module import time. Uvicorn imports the user app from inside its own running loop, so every pod crashed withRuntimeError: asyncio.run() cannot be called from a running event loop.This hotfix moves the strip into the right place per transport:
asyncio.run(_strip_internal_schema_fields())inside_run_stdio()beforemcp.run()boots its own loop.The strip itself is unchanged behaviorally —
api_tokenandmanagedByare still hidden from the schema, just at the right time now.Test plan
uv run pytest)TestImportFromRunningLoopDoesNotCrashreloads the module from inside anasyncio.runand assertsapi_tokenis gone after lifespan entry — this would have failed before the fixpython -c "asyncio.run(import devhelm_mcp.server; lifespan...)"succeedsCuts to v0.7.2 to supersede the broken v0.7.1.
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