Server fails & shutdown, npx agentdb for Claude Desktop

When adding agentdb to Claude Desktop (claude_desktop_config.json):

"agentdb": {
"command": "npx",
"args": ["agentdb@latest", "mcp", "start"]
}

The server starts with errors, fails and shut-down.

2025-10-25T05:32:48.244Z [agentdb] [info] Initializing server... { metadata: undefined }
2025-10-25T05:32:48.272Z [agentdb] [info] Using MCP server command: /usr/local/bin/npx with args and path: {
metadata: {
args: [ 'agentdb@latest', 'mcp', 'start', [length]: 3 ],
paths: [
'/usr/local/bin',
'/usr/bin',
'/usr/bin',
'/bin',
'/usr/sbin',
'/sbin',
[length]: 6
]
}
} %o
2025-10-25T05:32:48.274Z [agentdb] [info] Server started and connected successfully { metadata: undefined }
2025-10-25T05:32:48.310Z [agentdb] [info] Message from client: {"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"claude-ai","version":"0.1.0"}},"jsonrpc":"2.0","id":0} { metadata: undefined }
npm warn exec The following package was not found and will be installed: agentdb@1.4.3
2025-10-25T05:32:52.406Z [agentdb] [error] Unexpected token '', "ℹ Sta"... is not valid JSON {
metadata: {
context: 'connection',
stack: SyntaxError: Unexpected token '\x1B', "\x1B[34mℹ Sta"... is not valid JSON\n +
' at JSON.parse ()\n' +
' at dce (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:193:207)\n' +
' at fce.readMessage (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:193:133)\n' +
' at mce.processReadBuffer (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:194:2201)\n' +
' at Socket. (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:194:1651)\n' +
' at Socket.emit (node:events:519:28)\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)'
}
}
2025-10-25T05:32:52.466Z [agentdb] [error] Unexpected token '✅', "✅ Using sq"... is not valid JSON {
metadata: {
context: 'connection',
stack: SyntaxError: Unexpected token '✅', "✅ Using sq"... is not valid JSON\n +
' at JSON.parse ()\n' +
' at dce (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:193:207)\n' +
' at fce.readMessage (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:193:133)\n' +
' at mce.processReadBuffer (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:194:2201)\n' +
' at Socket. (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:194:1651)\n' +
' at Socket.emit (node:events:519:28)\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)'
}
}
Transformers.js not available, falling back to mock embeddings
🚀 AgentDB MCP Server v1.3.0 running on stdio
📦 29 tools available (5 core vector DB + 9 frontier + 10 learning + 5 AgentDB tools)
🧠 Embedding service initialized
🎓 Learning system ready (9 RL algorithms)
✨ New learning tools: metrics, transfer, explain, experience_record, reward_signal
🔬 Extended features: transfer learning, XAI explanations, reward shaping
2025-10-25T05:32:52.611Z [agentdb] [info] Server transport closed { metadata: undefined }
2025-10-25T05:32:52.611Z [agentdb] [info] Client transport closed { metadata: undefined }
2025-10-25T05:32:52.612Z [agentdb] [info] Server transport closed unexpectedly, this is likely due to the process exiting early. If you are developing this MCP server you can add output to stderr (i.e. console.error('...') in JavaScript, print('...', file=sys.stderr) in python) and it will appear in this log. { metadata: undefined }
2025-10-25T05:32:52.612Z [agentdb] [error] Server disconnected. For troubleshooting guidance, please visit our debugging documentation { metadata: { context: 'connection', stack: undefined } }
2025-10-25T05:32:52.613Z [agentdb] [info] Client transport closed { metadata: undefined }

Start with the claude_desktop_config.json entry and run the exact npx agentdb@latest mcp start command while observing stdout and stderr separately. Trace the MCP startup output and verify that the stdio stream emits only valid JSON-RPC messages, with the server remaining connected after initialization.