René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"how to manage multi streamable http server lifespan","articleBody":"**Describe the bug**\nI write a multi streamable http server example according to your readme doc, but only the mcp server which pass the session_manager.run() to FastAPI works right\n\n**To Reproduce**\nmcp python sdk  ver 1.8.1\n\nmcp server code\n```python\nfrom fastapi import FastAPI\nimport uvicorn\nfrom mcp.server.fastmcp import FastMCP\n\n\necho_mcp = FastMCP(name=\"EchoServer\", stateless_http=True)\n\n\n@echo_mcp.tool(description=\"A simple echo tool\")\ndef echo(message: str) -\u003e str:\n    return f\"Echo: {message}\"\n\nmath_mcp = FastMCP(name=\"MathServer\", stateless_http=True)\n\n\n@math_mcp.tool(description=\"A simple add tool\")\ndef add_two(m: int, n: int) -\u003e int:\n    return m + n\n\n\napp = FastAPI(lifespan=lambda app: echo_mcp.session_manager.run())\napp.mount(\"/echo\", echo_mcp.streamable_http_app())\napp.mount(\"/math\", math_mcp.streamable_http_app())\n\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8000)\n```\n\nmcp client code\n```python\nimport asyncio\nfrom mcp import ClientSession\nfrom mcp.client.streamable_http import streamablehttp_client\n\n\nasync def main():\n    server_url = \"http://127.0.0.1:8000/math/mcp\"\n\n    async with streamablehttp_client(server_url) as (read, write, _):\n        async with ClientSession(read, write) as session:\n            await session.initialize()\n            tools = await session.list_tools()\n            tools = tools.tools\n\n            print(f\"found {len(tools)} tools:\")\n\nif __name__ == \"__main__\":\n    asyncio.run(main())\n```\n\n\n**Expected behavior**\nEvery mcp server works right.\n\n**Error Stack**\n```SHELL\n/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/bin/python /Users/karsalina/PycharmProjects/playGround/script/http_server.py \nINFO:     Started server process [44368]\nINFO:     Waiting for application startup.\n[05/14/25 16:21:02] INFO     StreamableHTTP       streamable_http_manager.py:109\n                             session manager                                    \n                             started                                            \nINFO:     Application startup complete.\nINFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)\nINFO:     127.0.0.1:49685 - \"POST /math/mcp HTTP/1.1\" 307 Temporary Redirect\nINFO:     127.0.0.1:49687 - \"POST /math/mcp/ HTTP/1.1\" 500 Internal Server Error\nERROR:    Exception in ASGI application\nTraceback (most recent call last):\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/uvicorn/protocols/http/httptools_impl.py\", line 411, in run_asgi\n    result = await app(  # type: ignore[func-returns-value]\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/uvicorn/middleware/proxy_headers.py\", line 69, in __call__\n    return await self.app(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/fastapi/applications.py\", line 1054, in __call__\n    await super().__call__(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/applications.py\", line 112, in __call__\n    await self.middleware_stack(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/middleware/errors.py\", line 187, in __call__\n    raise exc\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/middleware/errors.py\", line 165, in __call__\n    await self.app(scope, receive, _send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/middleware/exceptions.py\", line 62, in __call__\n    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/_exception_handler.py\", line 53, in wrapped_app\n    raise exc\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/_exception_handler.py\", line 42, in wrapped_app\n    await app(scope, receive, sender)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/routing.py\", line 714, in __call__\n    await self.middleware_stack(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/routing.py\", line 734, in app\n    await route.handle(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/routing.py\", line 460, in handle\n    await self.app(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/applications.py\", line 112, in __call__\n    await self.middleware_stack(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/middleware/errors.py\", line 187, in __call__\n    raise exc\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/middleware/errors.py\", line 165, in __call__\n    await self.app(scope, receive, _send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/middleware/exceptions.py\", line 62, in __call__\n    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/_exception_handler.py\", line 53, in wrapped_app\n    raise exc\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/_exception_handler.py\", line 42, in wrapped_app\n    await app(scope, receive, sender)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/routing.py\", line 714, in __call__\n    await self.middleware_stack(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/routing.py\", line 734, in app\n    await route.handle(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/starlette/routing.py\", line 460, in handle\n    await self.app(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/mcp/server/fastmcp/server.py\", line 782, in handle_streamable_http\n    await self.session_manager.handle_request(scope, receive, send)\n  File \"/Users/karsalina/Library/Caches/pypoetry/virtualenvs/playground-p-gXMEVB-py3.10/lib/python3.10/site-packages/mcp/server/streamable_http_manager.py\", line 137, in handle_request\n    raise RuntimeError(\"Task group is not initialized. Make sure to use run().\")\nRuntimeError: Task group is not initialized. Make sure to use run().\n```","author":{"url":"https://github.com/AniviaTn","@type":"Person","name":"AniviaTn"},"datePublished":"2025-05-14T08:24:51.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":18},"url":"https://github.com/713/python-sdk/issues/713"}