René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"SSE Connection Failure Described as \"throw new Error(\"Not connected\")\"","articleBody":"**Describe the bug**\nMCP initialization stucked at \"Set up MCP Proxy\" with node_modules/@modelcontextprotocol/sdk/dist/esm/server/sse.js:103\nthrow new Error(\"Not connected\") on Windows 11 24H2. I doubt that this shouldn't be a bug but could be misconfiguration.\n\n**To Reproduce**\nSteps to reproduce the behavior:\n1. Minimal walkthrough of installation.\n2. npm cache clean --force\n3. Copy\u0026Paste simple MCP server.py at QuickStart. (https://github.com/modelcontextprotocol/python-sdk?tab=readme-ov-file#quickstart)\n4. mcp dev server.py\n5. Error with SSE. Logs below:\n```\nStarting MCP inspector...\n⚙️ Proxy server listening on port 6277\n🔍 MCP Inspector is up and running at http://127.0.0.1:6274 🚀\nStdio transport: command=C:\\Program Files\\Python311\\Scripts\\uv.exe, args=run,--with,mcp,mcp,run,test_server.py\nSpawned stdio transport\nConnected MCP client to backing server transport\nCreated web app transport\nCreated web app transport\nSet up MCP proxy\nfile:///C:/.../node_modules/@modelcontextprotocol/sdk/dist/esm/server/sse.js:103\n            throw new Error(\"Not connected\");\n                  ^\n\nError: Not connected\n    at SSEServerTransport.send (file:///C:/.../node_modules/@modelcontextprotocol/sdk/dist/esm/server/sse.js:103:19)\n    at Socket.\u003canonymous\u003e (file:///C:/.../node_modules/@modelcontextprotocol/inspector/server/build/index.js:101:33)\n    at Socket.emit (node:events:507:28)\n    at addChunk (node:internal/streams/readable:559:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:510:3)\n    at Readable.push (node:internal/streams/readable:390:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)\n\nNode.js v23.11.0\n```\n\n**Expected behavior**\nConnection through SSE should be established.\n\n**Screenshots**\nI shall provide detailed log output and actively participating discussion. I'd be glad to hear if there's anything I could provide.\n\n**Desktop (please complete the following information):**\n - OS: Windows 11 24H2\n - Browser Thorium / Edge / Chromium\n - Version 26100.3624\n\n**Additional context**\nGratitude on active development. Shame on me triggering low-level weird bugs.\n","author":{"url":"https://github.com/Ishiharaerika","@type":"Person","name":"Ishiharaerika"},"datePublished":"2025-04-04T21:28:24.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/433/python-sdk/issues/433"}