The agent framework throws a CancelledError during MCP tool execution, occurring after tool functions execute successfully.

[kmoyya]

response = await agent.run(messages=request.user_query)

Log Pattern:
[timestamp] - agent_framework - INFO - Function [name] succeeded.
[timestamp] - agent_framework - DEBUG - Function result: [result_object]
[timestamp] - agent_framework - DEBUG - _try_execute_function_calls: tool_map keys=[...]
[timestamp] - agent_framework - DEBUG - Checking function call: type=function_call, name=[name]
CancelledError('Cancelled by cancel scope [id]')

Any body faced similar error? What can be the probable reason behind this? Highly Appreciate any pointers

[eavanvalkenburg]

@kmoyya there's not much to go on here, I think the cancellederror itself is coming from the MCP package, so please share a bit of code of how you setup the mcp server, and any logs you can get (with logging level on debug)

[kmoyya]

Thanks @eavanvalkenburg for the reply, here is the additional info requested, sharing logs from both MCP server side (running locally) and client side:

Timeline Analysis

MCP Server Side (All Successful):

  - 08:43:04: Initialization (Ping, ListTools, ListPrompts) - All return 200
  - 08:43:18-20: tool_1 - 1.7s execution, SUCCESS (200)
  - 08:43:36-42: Two parallel tool_2 calls:
    - Call 1: 1.86s execution, SUCCESS (200)
    - Call 2: 5.33s execution, SUCCESS (200)

Client Side:

  - 08:43:01: Start agent.run()
  - 08:43:04: MCP connection established successfully
  - 08:43:18-20: tool_1 succeeds
  - 08:43:36-42: Both tool_2 calls succeed
  - After 08:43:42: CancelledError('Cancelled by cancel scope 153fed880') thrown

Appreciate any pointers here

[kmoyya]

Update: I configured the timeout for MCP connections, and now the run is no longer terminating in between

timeout_config = httpx.Timeout(
                connect=5.0,  # Connection timeout
                read=LLM_CLIENT_TIMEOUT * 2,  
                write=5.0,  # Write timeout
                pool=10.0  # Pool timeout
            )

http_client = httpx.AsyncClient(
    headers=http_headers,
    follow_redirects=True,
    timeout=timeout_config  # Explicit timeout configuration
)

   
mcp_tool = MCPStreamableHTTPTool(
    name=server_name,
    url=server_config.endpoint,
    http_client=http_client,
    allowed_tools=allowed_tools,
    request_timeout=MCP_SERVER_TIMEOUT,
)