Gemini CLI litmus check_server

How to: Gemini CLI litmus check_server

client:Gemini CLI transport:streamable-http tool:check_server

Add litmus to Gemini CLI

01
Open ~/.gemini/settings.json and merge this in. Keep any servers already there.

{
  "mcpServers": {
    "litmus": {
      "httpUrl": "https://polygraph.so/api/mcp"
    }
  }
}

02
Save the file and restart Gemini CLI.
03
Ask for something check_server does. Gemini CLI lists the server's tools on connect and calls check_server itself — you do not invoke it by name.
04
If nothing happens, check the server is running and that litmus's identifier in your config matches the one above exactly.

Gemini expands $VAR and ${VAR} inside env values, so a secret can live in your shell rather than this file. Gemini CLI docs

Set these first

litmus will not start until these are set, so check_server never becomes available.

POLYGRAPH_API_URL
NEXT_PUBLIC_POLYGRAPH_NETWORK

Same tool, other clients

This list was read from the server itself, by connecting to it and calling tools/list on 24 September 2026. It is what the server actually exposes, not what its listing claims.

Mutating and Read-only are read off each tool's name, not its schema — a hint, not a guarantee. The registry stores tool names only; connect the server for its live schemas.

litmus MCP server