fix: return 400 instead of 500 when body read fails in stateless mode#817
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maciej-kisiel merged 1 commit intomodelcontextprotocol:mainfrom Feb 27, 2026
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This seems reasonable. Will let Maciej approve.
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Co-authored-by: Cursor <cursoragent@cursor.com> Made-with: Cursor
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Summary
Changes
http.StatusInternalServerErrortohttp.StatusBadRequestwhenio.ReadAll(req.Body)fails during stateless mode initialization in the streamable HTTP handler.Fixes #816
Rationale
Body read failures are client-side errors (disconnection, timeout, incomplete request), not server errors. Returning 500 is misleading and causes unnecessary alert fatigue for users monitoring their MCP servers.
This makes the behavior consistent with
servePOSTwhich already returns 400 for the same error condition.Testing