fix(core): use sessionId for MCP transport correlation#19172
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fix(core): use sessionId for MCP transport correlation#19172
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…n spans This introduces `recordInputs` and `recordOutputs` options to the MCP server wrapper and related functions, allowing for more granular control over the data captured in spans.
…to avoid breaking changes
…t input/output handlin
Wrapper transports (like NodeStreamableHTTPServerTransport wrapping WebStandardStreamableHTTPServerTransport) proxy onmessage/send via getters/setters, causing different 'this' values in each callback. This changes correlation from WeakMap<transport> to Map<sessionId> to correctly correlate requests with responses regardless of which transport object reference is used. Reported-by: @gotenxds
Add mock wrapper transport utility and tests verifying that instrumentation correctly handles transports that proxy onmessage/send via getters/setters (common pattern with StreamableHTTP transports).
Add E2E tests for MCP StreamableHTTP transport across node-express, node-express-v5, and tsx-express test applications. Tests verify that transactions are recorded correctly for the wrapper transport pattern used by NodeStreamableHTTPServerTransport.
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Codecov Results 📊Generated by Codecov Action |
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Codecov Results 📊✅ 23 passed | ⏭️ 7 skipped | Total: 30 | Pass Rate: 76.67% | Execution Time: 10.04s All tests are passing successfully. Generated by Codecov Action |
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node-overhead report 🧳Note: This is a synthetic benchmark with a minimal express app and does not necessarily reflect the real-world performance impact in an application.
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Summary
Fixes MCP server instrumentation not recording events for wrapper transport patterns (like
NodeStreamableHTTPServerTransportwhich wrapsWebStandardStreamableHTTPServerTransport).The root cause: wrapper transports proxy
onmessage/sendvia getters/setters, causing differentthisvalues. The previousWeakMap<transport, ...>correlation couldn't match requests to responses. This changes toMap<sessionId, ...>correlation which works regardless of transport object reference.Changes
correlation.tsto use sessionId-based Maps instead of transport-based WeakMapssessionManagement.tsto use sessionId-based session lookupTest Plan
cd packages/core && yarn test(2010 tests pass)yarn lint) & (yarn test).Closes getsentry/sentry-mcp#767
Thanks @gotenxds for reporting and debugging this issue!