Add warning log when rejecting request with unknown/expired session ID#2212
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rameshreddy-adutla wants to merge 2 commits intomodelcontextprotocol:mainfrom
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The else branch in _handle_stateful_request() silently returns 404 when a request has an unknown or expired session ID. The other two branches (existing session, new session) both log at debug/info level. Add a logger.warning() call so operators can diagnose why client connections are being rejected, e.g. after a server restart when clients send stale session IDs. Fixes modelcontextprotocol#2204 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Summary
Add a
logger.warning()call in theelsebranch ofStreamableHTTPSessionManager._handle_stateful_request()when rejecting a request with an unknown or expired session ID.Problem
The
elsebranch silently returns HTTP 404 without any logging. The other two branches both log:logger.debug("Session already exists...")(existing session)logger.info("Created new transport...")(new session)This made it very difficult to diagnose connection failures in production — for example, after a server restart when clients continued sending stale
mcp-session-idheaders. Operators had to wrap the ASGI app in custom middleware just to see why requests were being rejected.Fix
Add
logger.warning()with the rejected session ID before returning the 404 response. Usingwarninglevel (notdebug/info) since this typically indicates a problem that operators should investigate.Testing
Existing test
test_unknown_session_id_returns_404passes and now shows the warning in log output:Fixes #2204