error whan launching mcp server with claude

[flenoir]

Hi,

First of all thanks for this project.

i'm trying to use it with claude so i did build the image.

my claude config file is (prometheus url is hidden) :

{
  "mcpServers": {
    "prometheus": {
      "command": "docker",
      "args": [
        "run",
        "--rm",
        "-i",
        "-e", "PROMETHEUS_URL",
        "-e", "PROMETHEUS_USERNAME",
        "-e", "PROMETHEUS_PASSWORD",
        "prometheus-mcp-server"
      ],
      "env": {
        "PROMETHEUS_URL": "http://xxxx/select/0/prometheus",
        "PROMETHEUS_USERNAME": "",
        "PROMETHEUS_PASSWORD": ""
      }
    }
  }
}

Prometheus has no authentification.

when i launch claude, i get some errors like below :

2025-04-03T07:11:29.079Z [prometheus] [error] Unexpected token 'N', "No .env fi"... is not valid JSON {"context":"connection","stack":"SyntaxError: Unexpected token 'N', \"No .env fi\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at L$e (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:189)\n    at N$e.readMessage (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:115)\n    at j$e.processReadBuffer (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1842)\n    at Socket.<anonymous> (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1523)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)"}
2025-04-03T07:11:29.080Z [prometheus] [error] Unexpected token 'P', "Prometheus"... is not valid JSON {"context":"connection","stack":"SyntaxError: Unexpected token 'P', \"Prometheus\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at L$e (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:189)\n    at N$e.readMessage (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:115)\n    at j$e.processReadBuffer (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1842)\n    at Socket.<anonymous> (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1523)\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)"}
2025-04-03T07:11:29.081Z [prometheus] [error] Unexpected token 'S', "  Server URL"... is not valid JSON {"context":"connection","stack":"SyntaxError: Unexpected token 'S', \"  Server URL\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at L$e (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:189)\n    at N$e.readMessage (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:115)\n    at j$e.processReadBuffer (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1842)\n    at Socket.<anonymous> (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1523)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)"}
2025-04-03T07:11:29.081Z [prometheus] [error] Unexpected token 'A', "Authentica"... is not valid JSON {"context":"connection","stack":"SyntaxError: Unexpected token 'A', \"Authentica\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at L$e (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:189)\n    at N$e.readMessage (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:115)\n    at j$e.processReadBuffer (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1842)\n    at Socket.<anonymous> (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1523)\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)"}
2025-04-03T07:11:29.082Z [prometheus] [error] Unexpected end of JSON input {"context":"connection","stack":"SyntaxError: Unexpected end of JSON input\n    at JSON.parse (<anonymous>)\n    at L$e (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:189)\n    at N$e.readMessage (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:115)\n    at j$e.processReadBuffer (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1842)\n    at Socket.<anonymous> (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1523)\n    at Socket.emit (node:events:518:28)\n    at addChunk (node:internal/streams/readable:561:12)\n    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)\n    at Readable.push (node:internal/streams/readable:392:5)\n    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)"}
2025-04-03T07:11:29.082Z [prometheus] [error] Unexpected token 'S', "Starting P"... is not valid JSON {"context":"connection","stack":"SyntaxError: Unexpected token 'S', \"Starting P\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at L$e (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:189)\n    at N$e.readMessage (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:108:115)\n    at j$e.processReadBuffer (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1842)\n    at Socket.<anonymous> (/usr/lib/claude-desktop/app.asar/.vite/build/index.js:109:1523)\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)"}

Did i missed some configuration ?