René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Error from MCP server: SyntaxError: Unexpected token 'E', \"Error: typ\"... is not valid JSON","articleBody":"When i run the app with \ncmd = mcp dev server.py\n\nthen when i click on connect  button i got this issue\n\nStdio transport: command=C:\\Users\\User\\AppData\\Local\\Programs\\Python\\Python310\\Scripts\\uv.exe, args=run,--with,mcp,mcp,run,server.py\nSpawned stdio transport\nConnected MCP client to backing server transport\nCreated web app transport\nCreated web app transport\nSet up MCP proxy\nError from MCP server: SyntaxError: Unexpected token 'E', \"Error: typ\"... is not valid JSON\n    at JSON.parse (\u003canonymous\u003e)\n    at deserializeMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:26:44)\n    at ReadBuffer.readMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:19:16)\n    at StdioClientTransport.processReadBuffer (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:114:50)\n    at Socket.\u003canonymous\u003e (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:93:22)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)\nError from MCP server: SyntaxError: Unexpected token 'E', \"Error: typ\"... is not valid JSON\n    at JSON.parse (\u003canonymous\u003e)\n    at deserializeMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:26:44)\n    at ReadBuffer.readMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:19:16)\n    at StdioClientTransport.processReadBuffer (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:114:50)\n    at Socket.\u003canonymous\u003e (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:93:22)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)\nError from MCP server: SyntaxError: Unexpected token 'E', \"Error: typ\"... is not valid JSON\n    at JSON.parse (\u003canonymous\u003e)\n    at deserializeMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:26:44)\n    at ReadBuffer.readMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:19:16)\n    at StdioClientTransport.processReadBuffer (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:114:50)\n    at Socket.\u003canonymous\u003e (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:93:22)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)\nError from MCP server: SyntaxError: Unexpected token 'E', \"Error: typ\"... is not valid JSON\n    at JSON.parse (\u003canonymous\u003e)\n    at deserializeMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:26:44)\n    at ReadBuffer.readMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:19:16)\n    at StdioClientTransport.processReadBuffer (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:114:50)\n    at Socket.\u003canonymous\u003e (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:93:22)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)\nError from MCP server: SyntaxError: Unexpected token 'E', \"Error: typ\"... is not valid JSON\n    at JSON.parse (\u003canonymous\u003e)\n    at deserializeMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:26:44)\n    at ReadBuffer.readMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/stdio.js:19:16)\n    at StdioClientTransport.processReadBuffer (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:114:50)\n    at Socket.\u003canonymous\u003e (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:93:22)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)\nReceived message for sessionId ac082c68-292e-4cbd-b85e-42046b434b38\nError in /message route: Error: SSE connection not established\n    at SSEServerTransport.handlePostMessage (file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/server/sse.js:53:19)\n    at file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/inspector/server/build/index.js:129:25\n    at Layer.handle [as handle_request] (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\layer.js:95:5)\n    at next (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\route.js:149:13)\n    at Route.dispatch (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\route.js:119:3)\n    at Layer.handle [as handle_request] (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\layer.js:95:5)\n    at C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\index.js:284:15\n    at Function.process_params (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\index.js:346:12)\n    at next (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\router\\index.js:280:10)\n    at cors (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\cors\\lib\\index.js:188:7)\nnode:_http_outgoing:699\n    throw new ERR_HTTP_HEADERS_SENT('set');\n          ^\n\nError [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client\n    at ServerResponse.setHeader (node:_http_outgoing:699:11)\n    at ServerResponse.header (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\response.js:794:10)\n    at ServerResponse.json (C:\\Users\\User\\AppData\\Local\\npm-cache\\_npx\\5a9d879542beca3a\\node_modules\\express\\lib\\response.js:275:10)\n    at file:///C:/Users/User/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/inspector/server/build/index.js:133:25\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5) {\n  code: 'ERR_HTTP_HEADERS_SENT'\n}\n\nNode.js v22.14.0","author":{"url":"https://github.com/abdulsaminexusaeon","@type":"Person","name":"abdulsaminexusaeon"},"datePublished":"2025-04-02T08:33:06.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":11},"url":"https://github.com/409/python-sdk/issues/409"}