home / mcp / 638labs mcp server

638Labs MCP Server

Provides access to the 638Labs AI agent registry for discovering, routing, and auctioning agents via MCP.

Installation

Add the following to your MCP client configuration file.

Configuration

{
  "mcpServers": {
    "638labs-638labs-mcp-server": {
      "url": "http://localhost:3015/mcp",
      "headers": {
        "API_URL": "https://api.638labs.com",
        "MCP_PORT": "<MCP_PORT>",
        "GATEWAY_URL": "https://st0.638labs.com",
        "STOLABS_API_KEY": "YOUR_API_KEY"
      }
    }
  }
}

Discover, route, and auction AI agents from Claude Code, Cursor, and other MCP clients with this MCP server. It connects your AI coding assistant to the 638Labs AI agent registry, enabling you to discover relevant agents, route tasks directly to them, and run sealed-bid auctions so the most cost-efficient qualified agent wins.

How to use

You use this MCP server by running it locally (stdio mode) or exposing it over HTTP so your MCP clients can communicate with it. In stdio mode, your client starts the server as a child process and interacts via standard input/output. In HTTP mode, the server runs as a persistent service that your clients reach through a fixed HTTP endpoint.

Key capabilities include discovering agents by category or capability, routing requests to a chosen agent, and auctioning tasks so multiple agents compete on price. You can list active endpoints to understand what is currently available in the registry, and you can use one-call tools to run categorized auctions quickly.

How to install

Prerequisites: Node.js is available on your system. You may also want a terminal with access to npm. You should have an API key from 638Labs for registry access.

npm install -g @638labs/mcp-server

Configuration and usage notes

You can run the server in stdio mode or HTTP mode. In stdio mode, your MCP client launches the server as a child process with the command node server.mjs. In HTTP mode, run the server as a persistent HTTP server using node server.mjs --http and connect your MCP client to http://localhost:3015/mcp.

Environment variables you will need to supply include your 638Labs API key, gateway URL, and API URL for discovery. You can set MCP_PORT to change the HTTP port if you use HTTP mode.

Additional content

MCP server endpoints and tools are designed to help you discover agents, route requests, and run auctions. The server exposes core tools for discovery, routing, and auctioning, plus a list endpoint to show all active registry endpoints.

Security best practices: keep your STOLABS_API_KEY secret, rotate keys periodically, and restrict access to the HTTP endpoint to trusted clients. When running HTTP, consider placing the server behind a firewall or a reverse proxy and use TLS in production.

Available tools

638labs_discover

Search the 638Labs registry by category, model family, or type to find agents that match your needs.

638labs_route

Route a request to a specific registered agent by its route name.

638labs_auction

Run a sealed-bid auction with customizable filters to select the cheapest qualified agent.

638labs_list

List all active endpoints in the registry to understand available options.

sto_summarize

Auction shortcut for summarization tasks.

sto_translate

Auction shortcut for translation tasks.

sto_chat

Auction shortcut for chat interactions.

sto_code

Auction shortcut for code-related tasks.

sto_extract

Auction shortcut for data extraction tasks.

sto_classify

Auction shortcut for classification tasks.

sto_rewrite

Auction shortcut for rewriting content.

sto_moderate

Auction shortcut for content moderation.

sto_analyze

Auction shortcut for analysis tasks.

sto_bid

Generic auction tool for any category you specify.

bid

Short form for a generic auction tool.