rubber-duck

rubber-duck is a local MCP server: Bridge to multiple LLMs and CLI agents: councils, debates, voting, and more. Install it from npm as mcp-rubber-duck.

Claude CodeCodexAntigravity

commandprompt

Terminal

claude mcp add rubber-duck -e OPENAI_API_KEY=... -e GEMINI_API_KEY=... -e GROQ_API_KEY=... -e DEFAULT_PROVIDER=... -- npx -y mcp-rubber-duck

Run in your project folder. Add --scope user to use it everywhere.

Add to claude_desktop_config.json or .cursor/mcp.json.

{
  "mcpServers": {
    "rubber-duck": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-rubber-duck"
      ],
      "env": {
        "OPENAI_API_KEY": "...",
        "GEMINI_API_KEY": "...",
        "GROQ_API_KEY": "...",
        "DEFAULT_PROVIDER": "..."
      }
    }
  }
}

Fill in the environment variables with your own credentials.

• Runtime: Node.js 18+ (runs with npx).
• MCP client: Claude Code, Codex, Antigravity, Claude Desktop, Cursor or any other client that speaks MCP over stdio.
• Environment variables: OPENAI_API_KEY, GEMINI_API_KEY, GROQ_API_KEY, DEFAULT_PROVIDER