Use CasesAI Agent Payments

AI Agent Payments

Enable AI agents to pay for APIs and services autonomously using T402’s MCP (Model Context Protocol) integration.

Overview

AI agents need to access paid APIs, data sources, and compute resources. T402’s MCP server enables:

  • Autonomous payments: Agents pay for resources without human intervention
  • Budget controls: Set spending limits per session or request
  • Multi-chain support: Pay with USDT on any supported network
  • Seamless integration: Works with Claude, GPT, and other MCP-compatible agents

Architecture

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   AI Agent  │────▶│  MCP Server │────▶│  Paid API   │
│  (Claude)   │     │  (@t402/mcp)│     │  (T402)     │
└─────────────┘     └─────────────┘     └─────────────┘
                           │
                           ▼
                    ┌─────────────┐
                    │   Wallet    │
                    │  (Signer)   │
                    └─────────────┘

Setup MCP Server

1. Install the Package

pnpm add @t402/mcp

2. Configure Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "t402": {
      "command": "npx",
      "args": ["@t402/mcp"],
      "env": {
        "T402_PRIVATE_KEY": "0x...",
        "T402_NETWORK": "eip155:8453",
        "T402_MAX_AMOUNT": "1.00"
      }
    }
  }
}

3. Environment Variables

VariableDescriptionExample
T402_PRIVATE_KEYWallet private key for signing payments0x...
T402_NETWORKDefault network for paymentseip155:8453 (Base)
T402_MAX_AMOUNTMaximum payment per request1.00 (USDT)
T402_FACILITATOR_URLCustom facilitator URL (optional)https://facilitator.t402.io

Usage Examples

Basic API Access

When Claude encounters a 402 Payment Required response, it will automatically:

  1. Parse the payment requirements from the response
  2. Sign a payment authorization
  3. Retry the request with the payment header
  4. Return the response to you
User: "Get the latest market data from api.example.com/premium/markets"

Claude: I'll access that API for you. It requires a payment of $0.01 USDT.
[Automatically pays and retrieves data]

Here's the market data...

Budget Management

Set spending limits to control costs:

{
  "env": {
    "T402_MAX_AMOUNT": "0.10",
    "T402_DAILY_LIMIT": "10.00"
  }
}

Building T402-Enabled APIs

Create APIs that AI agents can pay to access:

import express from 'express'
import { paymentMiddleware } from '@t402/express'
 
const app = express()
 
app.use(paymentMiddleware({
  'GET /api/market-data': {
    price: '$0.01',
    network: 'eip155:8453',
    payTo: '0xYourAddress...',
    description: 'Real-time market data'
  },
  'POST /api/analyze': {
    price: '$0.05',
    network: 'eip155:8453',
    payTo: '0xYourAddress...',
    description: 'AI-powered analysis'
  }
}))
 
app.get('/api/market-data', (req, res) => {
  res.json({ btc: 45000, eth: 2500 })
})
 
app.listen(3000)

Security Considerations

⚠️

Private Key Security: Never commit private keys to version control. Use environment variables or secure secret management.

  • Spending Limits: Always set T402_MAX_AMOUNT to prevent unexpected charges
  • Network Selection: Use testnets for development (eip155:84532 for Base Sepolia)
  • Key Rotation: Regularly rotate wallet keys for production deployments

Best Practices

  1. Start with testnets: Use Base Sepolia or other testnets for development
  2. Set conservative limits: Start with low T402_MAX_AMOUNT values
  3. Monitor spending: Track payments in your wallet or via facilitator logs
  4. Use dedicated wallets: Create separate wallets for AI agent payments

Next Steps

OverviewAPI Monetization