fix: upgrade mcp SDK to v1.x branch to fix ClosedResourceError#84
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bolinocroustibat wants to merge 3 commits intomainfrom
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fix: upgrade mcp SDK to v1.x branch to fix ClosedResourceError#84bolinocroustibat wants to merge 3 commits intomainfrom
bolinocroustibat wants to merge 3 commits intomainfrom
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The mcp SDK 1.26.0 crashes stateless sessions with ClosedResourceError when a client disconnects mid-request. This causes memory leaks in production as session resources (task groups, memory streams) are not properly cleaned up. The fix (PRs #2257, #2306, backported in #2334) is on the v1.x branch but not yet released on PyPI. Pin to the branch until a new release is published. Made-with: Cursor
nicolaskempf57
approved these changes
Mar 27, 2026
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Thanks @nicolaskempf57 . I won't merge this until this is tested for a few days with high traffic. Fix has just been deployed to production to see if it mitigates the issue. |
This was referenced Mar 31, 2026
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Wrong culprit, see #86, closing |
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Related to #86
In production, client disconnects during MCP requests cause
ClosedResourceErrorcrashes in stateless sessions.This is a known bug in
mcp1.26.0, fixed upstream by:Session resources/memory might not be properly cleaned up on those crashes, which could explain memory leaks that eventually OOM the container.
No PyPI release includes these fixes yet (latest is 1.26.0), so this pins to the
v1.xbranch directly. Revert to a PyPI specifier once a new release is published.