fix(mcp): recognise 'Session terminated' as transport session expiry#18143
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vominh1919 wants to merge 1 commit into
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fix(mcp): recognise 'Session terminated' as transport session expiry#18143vominh1919 wants to merge 1 commit into
vominh1919 wants to merge 1 commit into
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When a streamable-http MCP server restarts or its session is garbage-collected, the MCP SDK sends: McpError(ErrorData(code=32600, message='Session terminated')) This error was not in _SESSION_EXPIRED_MARKERS, so it fell through to the generic tool-failure path with no recovery. Every subsequent call on the affected MCP server would fail until the gateway was manually restarted. Add 'session terminated' to the markers tuple so the error is routed through the existing reconnect-and-retry flow (NousResearch#13383). Fixes NousResearch#18069
alt-glitch
added
type/bug
Collaborator
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Likely duplicate of #18069 — same fix adding "Session terminated" to _SESSION_EXPIRED_MARKERS in mcp_tool.py. |
Collaborator
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Likely duplicate of #18069 — same fix adding 'Session terminated' to _SESSION_EXPIRED_MARKERS in mcp_tool.py. |
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Problem
Fixes #18069
When a streamable-http MCP server restarts (or its session is garbage-collected due to idle TTL, pod rotation, etc.), the MCP SDK sends:
This error was not included in
_SESSION_EXPIRED_MARKERS, so it fell through to the generic tool-failure path with no recovery. Every subsequent call on the affected MCP server would fail until the gateway was manually restarted — even though the transport layer had already reconnected with a fresh session ID.Fix
Add
"session terminated"to_SESSION_EXPIRED_MARKERSintools/mcp_tool.pyso the error is routed through the existing reconnect-and-retry flow introduced in #13383.Before vs After
Session terminated(code 32600)expired session, etc.)Tests
tests/tools/test_mcp_tool_session_expired.py— addedtest_is_session_expired_detects_session_terminatedwith 2 assertions:"McpError(ErrorData(code=32600, message='Session terminated'))"→ detected"Session terminated"→ detected