@xmcp-dev/x402

x402 payment protocol plugin for xmcp. Add paid tools with USDC on Base.

Installation

pnpm add @xmcp-dev/x402

Usage

Middleware

// src/middleware.ts
import { x402Middleware } from "@xmcp-dev/x402";

export default x402Middleware({
  wallet: process.env.X402_WALLET!,
  defaults: {
    price: 0.01,
    network: "base-sepolia",
  },
});

Paid tools

// src/tools/my-tool.ts
import { paid } from "@xmcp-dev/x402";

export default paid(async ({ input }) => {
  return { content: [{ type: "text", text: `Result: ${input}` }] };
});

// src/tools/premium-tool.ts
import { paid } from "@xmcp-dev/x402";

export default paid({ price: 0.10 }, async ({ input }) => {
  return { content: [{ type: "text", text: `Premium: ${input}` }] };
});

Payment context

import { paid, payment } from "@xmcp-dev/x402";

export default paid(async ({ input }) => {
  const { payer, amount, network } = payment();
  return { content: [{ type: "text", text: `Paid by ${payer}` }] };
});

API

x402Middleware(config)

interface X402Config {
  wallet: string;
  facilitator?: string;
  debug?: boolean;
  defaults?: {
    price?: number;
    currency?: string;
    network?: string;
    maxPaymentAge?: number;
  };
}

paid(options?, handler)

interface X402ToolOptions {
  price?: number;
  currency?: string;
  network?: string;
  maxPaymentAge?: number;
  description?: string;
}

payment()

interface X402PaymentContext {
  payer: string;
  amount: string;
  network: string;
  asset: string;
  toolName: string;
  transactionHash?: string;
}

Networks

| Network | USDC Address | |---------|--------------| | base | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 | | base-sepolia | 0x036CbD53842c5426634e7929541eC2318f3dCF7e |

License

MIT