[Bug]: streamable_http - ERROR - Error in message router - ClosedResourceError

[MohanLaksh]

🐞 Bug Summary

The server intermittently disconnects due to an ERROR in streamable_http message router.

streamable_http - ERROR - Error in message router - ClosedResourceError

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🧩 Affected Component

Select the area of the project impacted:

• mcpgateway - API
• mcpgateway - UI (admin panel)
• mcpgateway.wrapper - stdio wrapper
• Federation or Transports
• CLI, Makefiles, or shell scripts
• Container setup (Docker/Podman/Compose)
• Other (explain below)

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🔁 Steps to Reproduce

1. make serve add a gateway with streamable_http transport type.

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🤔 Expected Behavior

What should have happened instead?

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📓 Logs / Error Output

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2025-08-21 07:46:26,221 - uvicorn.access - INFO - 127.0.0.1:45786 - "POST /mcp HTTP/1.1" 200
2025-08-21 07:46:26,222 - mcp.server.streamable_http - ERROR - Error in message router
Traceback (most recent call last):
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/mcp/server/streamable_http.py", line 831, in message_router
async for session_message in write_stream_reader:
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/anyio/abc/_streams.py", line 41, in anext
return await self.receive()
^^^^^^^^^^^^^^^^^^^^
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/anyio/streams/memory.py", line 111, in receive
return self.receive_nowait()
^^^^^^^^^^^^^^^^^^^^^
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/anyio/streams/memory.py", line 93, in receive_nowait
raise ClosedResourceError
anyio.ClosedResourceError
2025-08-21 07:46:26,241 - uvicorn.access - INFO - 127.0.0.1:45786 - "POST /mcp HTTP/1.1" 200
2025-08-21 07:46:26,241 - mcp.server.streamable_http - ERROR - Error in message router
Traceback (most recent call last):
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/mcp/server/streamable_http.py", line 831, in message_router
async for session_message in write_stream_reader:
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/anyio/abc/_streams.py", line 41, in anext
return await self.receive()
^^^^^^^^^^^^^^^^^^^^
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/anyio/streams/memory.py", line 111, in receive
return self.receive_nowait()
^^^^^^^^^^^^^^^^^^^^^
File "/home/mohanlaksh/.venv/mcpgateway/lib/python3.12/site-packages/anyio/streams/memory.py", line 93, in receive_nowait
raise ClosedResourceError
anyio.ClosedResourceError
2025-08-21 08:56:11,451 - uvicorn.access - INFO - 127.0.0.1:60360 - "GET /admin/servers/ed196d49fa624d778cb3b4a8e2a2d12d HTTP/1.1" 401
[2025-08-21 09:29:11 +0000] [1745] [INFO] Handling signal: winch

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🧠 Environment Info

You can retrieve most of this from the /version endpoint.

Key	Value
Version or commit	v0.5.0
Runtime	Python 3.12.3
Platform / OS	Ubuntu 22.04
Container	none

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🧩 Additional Context (optional)

Add any configuration details, flags, or related issues.