x402 MCP Server

An MCP (Model Context Protocol) server that exposes x402 DeFi data endpoints as tools for AI agents.

What is MCP?

MCP is an open standard that lets AI applications (Claude, Cursor, OpenClaw, etc.) discover and use tools through a unified protocol. Think of it as a USB-C port for AI — any compliant client can plug into any compliant server.

This server wraps the x402 API (pay-per-call DeFi data) so that any MCP-compatible AI agent can:

• Discover available data endpoints
• Call them with proper parameters
• Get structured results back

Tools

Prerequisites

1. The x402 API server must be running at localhost:4020 (or set X402_API_URL)
2. Node.js 18+

Setup

cd x402-mcp-server
npm install

Connect to Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "x402-defi": {
      "command": "node",
      "args": ["/absolute/path/to/x402-mcp-server/src/index.js"],
      "env": {
        "X402_API_URL": "http://localhost:4020"
      }
    }
  }
}

Connect to Cursor

Add to .cursor/mcp.json in your project (or global settings):

{
  "mcpServers": {
    "x402-defi": {
      "command": "node",
      "args": ["/absolute/path/to/x402-mcp-server/src/index.js"]
    }
  }
}

Connect to OpenClaw

openclaw mcp add x402-defi -- node /absolute/path/to/x402-mcp-server/src/index.js

Test Locally

# Start the x402 API server first
cd ../x402-api-server && npm start &

# Test MCP server with the MCP inspector
npx @modelcontextprotocol/inspector node src/index.js

# Or pipe JSON-RPC manually:
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0.0"}}}' | node src/index.js

Architecture

AI Agent (Claude/Cursor/OpenClaw)
    ↕ MCP (stdio, JSON-RPC)
x402 MCP Server (this)
    ↕ HTTP
x402 API Server (localhost:4020)
    ↕ x402 protocol (HTTP 402 + USDC)
DeFi Data Sources

License

MIT