jq-mcp

An MCP server that exposes a single tool, jq, for running jq filters against JSON files on disk.

Use

Add to your MCP client config:

{
  "mcpServers": {
    "jq-mcp": {
      "command": "npx",
      "args": ["jq-mcp@latest"]
    }
  }
}

The jq tool takes file and query and returns the stdout of jq <query> <file>. By default it can read files under the server's working directory and /tmp.

Advanced: custom allowlist

Set ALLOWED_PATHS (comma-separated directories) in the server's env to override the default <cwd>,/tmp:

"env": { "ALLOWED_PATHS": "/path/to/allow,/another/path" }

Path matching normalizes the input before comparing, so:

• .. segments cannot escape an allowed directory.
• Sibling directories that share a string prefix (e.g. /foo/bar-evil vs /foo/bar) are rejected — the check is path-boundary aware, not a naive startsWith.

Develop

npm test     # node:test suite
npm run build