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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"FastMCP.run(transport=\"stdio\") produces noisy traceback on KeyboardInterrupt instead of clean exit","articleBody":"### Initial Checks\n\n- [x] I confirm that I'm using the latest version of MCP Python SDK\n- [x] I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue\n\n### Description\n\nRunning a FastMCP stdio server from the terminal and interrupting with Ctrl-C produces a multi-frame traceback through anyio.run() → asyncio.runners → mcp.server.lowlevel.server.run → anyio.streams.memory.receive. The server is correctly waiting on stdin in an async loop; the trace surfaces because anyio/asyncio don't suppress the cancellation chain. Suggested fix: catch KeyboardInterrupt (or asyncio.CancelledError at the outer boundary) inside FastMCP.run and exit cleanly. Cosmetic but reduces user confusion when testing MCP servers from the terminal.\n\n### Example Code\n\n```Python\n\n```\n\n### Python \u0026 MCP Python SDK\n\n```Text\nPython 3.13.5\nMCP Python SDK 1.27.1\n```","author":{"url":"https://github.com/MikeNjoroge","@type":"Person","name":"MikeNjoroge"},"datePublished":"2026-05-22T12:00:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/2663/python-sdk/issues/2663"}