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mcp-http-drain-rejected-request-body - #805
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Early refusals (401 from the bearer check, 403 from cross-origin protection) answered without reading the request body; with a client sending Connection: close, Go then closed the socket with unread bytes, which resets the connection and a Windows client loses the response. The body is now drained (bounded) before the refusal is written. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
general-kroll-4-life
approved these changes
Oct 4, 2026
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Summary
Post-merge
Windows Buildonmain(ed962c9) failed inMCP HTTP Bearer Token AuthenticationwithConnectionResetError: [WinError 10054]. Reproduced locally on Windows: 6 of 30 anonymous (401) and 11 of 30 cross-origin (403) round trips reset; authenticated (200) never did.Cause: both refusals were written without reading the request body. The client sends
Connection: close, so Go closes the socket after the response while the body bytes are still unread when they arrived in a separate segment; that close is a TCP reset, and Windows discards the buffered response on reset. Linux clients read the buffered bytes first, which is why only Windows saw it.Fix:
rejectRequestdrains up to 64 KiB of the body before writing the 401 / 403 (bearer check and theCrossOriginProtectiondeny handler). One file, plus a unit test asserting the body is consumed on both refusals. Against the patched binary the same loop is 180 of 180 clean.Test plan
go test ./pkg/mcp_server/,golangci-lintv2.5.0: pass.Mcpsuite in WSL: 79 / 79.MCP HTTP Bearer Token Authenticationscenario is the regression test; CIWindows Buildis the proof.🤖 Generated with Claude Code