René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"404 Not Found Error when Establishing SSE Connection via MCP Python SDK","articleBody":"**Describe the bug**\nA clear and concise description of what the bug is.\n\nDescription​​\nWhen attempting to establish SSE connection with MCP Python SDK (v1.6.0), encountering persistent 404 errors on critical endpoints:\n\n`mcp = FastMCP(\"Demo\", debug=True, log_level=\"DEBUG\", message_path=\"/abcd/abcd/messages/\")\n`\n\n**To Reproduce**\nSteps to reproduce the behavior:\n1. Go to '...'\n2. Click on '....'\n3. Scroll down to '....'\n4. See error\n\n[04/14/25 09:45:51] DEBUG    Setting up SSE connection                 sse.py:87\n\n                    DEBUG    session_uri:                             sse.py:106\n\n                              /abcd/abcd/messages/?session_id\n                             =b5b93f9d4088442fa3edb1c679a7a922\n\n                    DEBUG    Created new session with ID:             sse.py:109\n                             b5b93f9d-4088-442f-a3ed-b1c679a7a922\n\n                    DEBUG    Starting SSE response task               sse.py:136\n\n                    DEBUG    Yielding read and write streams          sse.py:139\n\nINFO:     100.67.30.95:57894 - \"GET /sse HTTP/1.1\" 200 OK\n\n                    DEBUG    Starting SSE writer                      sse.py:116\n\n                    DEBUG    Sent endpoint event:                     sse.py:119\n                              /abcd/abcd/messages/?session_id\n                             =b5b93f9d4088442fa3edb1c679a7a922\n\n                    DEBUG    chunk: b'event: endpoint\\r\\ndata:        sse.py:156\n                             /abcd/abcd/messages/?session_id\n                             =b5b93f9d4088442fa3edb1c679a7a922\\r\\n\\r\\\n                             n'\n\nINFO:     10.183.49.44:60168 - \"GET /prometheus HTTP/1.1\" 404 Not Found\n\nINFO:     100.67.31.17:49088 - \"POST /messages/?session_id=b5b93f9d4088442fa3edb1c679a7a922 HTTP/1.1\" 404 Not \nFound\n\n                    DEBUG    Got event: http.disconnect. Stop         sse.py:177\n\n                             streaming.\n\n**Expected behavior**\nA clear and concise description of what you expected to happen.\n\n**Screenshots**\nIf applicable, add screenshots to help explain your problem.\n\n**Desktop (please complete the following information):**\n - OS: [e.g. iOS]\n - Browser [e.g. chrome, safari]\n - Version [e.g. 22]\n\n**Smartphone (please complete the following information):**\n - Device: [e.g. iPhone6]\n - OS: [e.g. iOS8.1]\n - Browser [e.g. stock browser, safari]\n - Version [e.g. 22]\n\n**Additional context**\nAdd any other context about the problem here.\n","author":{"url":"https://github.com/chi2liu","@type":"Person","name":"chi2liu"},"datePublished":"2025-04-14T09:52:57.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/507/python-sdk/issues/507"}