MCP

git clone https://github.com/snack-money/snack-money-examples.git
cd snack-money-examples/mcp
yarn install

# For Base (EVM) network
EVM_PRIVATE_KEY=0x...

# For Solana network
SVM_PRIVATE_KEY=...base58...

# Common settings
RECEIVER=username
AMOUNT=0.01
PLATFORM=twitter  # twitter, farcaster, email, github, web
API_URL=https://api.snack.money

yarn list-tools

{
  "tools": [
    {
      "name": "pay_twitter",
      "description": "Send USDC to a Twitter/X user",
      "inputSchema": { ... }
    },
    {
      "name": "pay_farcaster",
      "description": "Send USDC to a Farcaster user",
      "inputSchema": { ... }
    },
    // ... more tools
  ]
}

yarn base

yarn solana

import { X402 } from '@x402/core';
import { createEvmClient } from '@x402/evm';

// Initialize x402 client
const x402 = createEvmClient({
  privateKey: process.env.EVM_PRIVATE_KEY,
  chainId: 8453 // Base mainnet
});

// Make MCP call
async function callMcpTool(toolName: string, args: any) {
  // First attempt - will require payment
  const response = await fetch(`${API_URL}/mcp`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      jsonrpc: '2.0',
      method: 'tools/call',
      params: {
        name: toolName,
        arguments: args
      },
      id: 1
    })
  });

  const result = await response.json();

  // Check if payment required
  if (result.error?.code === -32402) {
    const { taskId, paymentRequired } = result.error.data;

    // Sign payment
    const signedPayment = await x402.createPaymentPayload(
      paymentRequired
    );

    // Retry with payment
    const paidResponse = await fetch(`${API_URL}/mcp`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'tools/call',
        params: {
          name: toolName,
          arguments: args,
          _meta: {
            taskId,
            x402Payment: signedPayment
          }
        },
        id: 2
      })
    });

    return paidResponse.json();
  }

  return result;
}

// Use the function
const result = await callMcpTool('pay_twitter', {
  receiver: 'alice',
  amount: 0.01,
  description: 'Thanks for the help!'
});

console.log('Payment sent:', result.result);