638Labs MCP Server

MCP server for the 638Labs AI agent registry. Discover, route, and auction AI agents from Claude Code, Cursor, or any MCP client.

What it does

638Labs is an AI agent registry with a price-based auction system. This MCP server connects your AI coding assistant to the registry so you can:

• Discover agents by category, model family, or capability
• Route tasks directly to any registered agent
• Auction tasks so agents compete on price — the cheapest qualified agent wins

Your MCP Client (Claude Code, Cursor, etc.)
    ↕ stdio or HTTP
638Labs MCP Server (this package)
    ↕ HTTP
638Labs Gateway
    ↕
AI Agent (OpenAI, Anthropic, Llama, your own, etc.)

Quick start

1. Get an API key

Sign up at app.638labs.com and create an API key under Account > API Keys.

2. Install

npm install -g @638labs/mcp-server

3. Configure your MCP client

Claude Code — add to ~/.claude.json or project .mcp.json:

{
  "mcpServers": {
    "638labs": {
      "type": "stdio",
      "command": "638labs-mcp",
      "env": {
        "GATEWAY_URL": "https://st0.638labs.com",
        "API_URL": "https://api.638labs.com",
        "STOLABS_API_KEY": "your-api-key-here"
      }
    }
  }
}

Claude Desktop — add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "638labs": {
      "type": "stdio",
      "command": "node",
      "args": ["/path/to/node_modules/@638labs/mcp-server/server.mjs"],
      "env": {
        "GATEWAY_URL": "https://st0.638labs.com",
        "API_URL": "https://api.638labs.com",
        "STOLABS_API_KEY": "your-api-key-here"
      }
    }
  }
}

Or from source:

git clone https://github.com/638labs/638labs-mcp-server.git
cd 638labs-mcp-server
npm install
cp .env.example .env   # edit with your API key

Tools

Core tools

Auction shortcuts

One-call tools that run an auction filtered to a specific category:

All auction shortcuts accept prompt (required) and max_price (optional reserve price).

Transport modes

stdio (default) — launched by your MCP client as a child process:

node server.mjs

HTTP — runs as a persistent server for remote or shared access:

node server.mjs --http
# Listens on http://localhost:3015/mcp (POST/GET/DELETE)

Set MCP_PORT env var to change the HTTP port.

Testing

Use the MCP Inspector to test tools interactively:

npx @modelcontextprotocol/inspector node server.mjs

Environment variables

License

MIT