pay-per-call-mcp — AI Agent Payment MCP Server

Pay-per-call USDC micropayments for any HTTP API. Give your AI agent a USDC spending wallet — works with Claude Desktop, Cursor, Cline, and any MCP client. No signup needed in Demo Mode.

📦 v0.5.2: This package forwards to agent-payment-mcp. Both names work — pay-per-call-mcp is kept for existing configs.

What it does

pay-per-call-mcp lets an AI agent pay for HTTP API calls with USDC — no human approval needed per call.

• Agent calls a tool → USDC deducted from its wallet → API responds
• Kill switch + per-session spend limit built in
• Demo Mode: try instantly without any account or balance

Try in 30 seconds (Demo Mode)

In Claude Desktop / Cursor / Cline — add to your MCP config:

{
  "mcpServers": {
    "pay-per-call": {
      "command": "npx",
      "args": ["-y", "pay-per-call-mcp"]
    }
  }
}

Leave LEMON_CAKE_BUYER_JWT unset → Demo Mode activates automatically. Calls hit real APIs (Wikipedia, httpbin, live FX rates) with no charges.

Live mode (real USDC)

1. Sign up at lemoncake.xyz
2. Top up with USDC (min $5)
3. Copy your Buyer JWT from the dashboard
4. Add to config:

{
  "mcpServers": {
    "pay-per-call": {
      "command": "npx",
      "args": ["-y", "pay-per-call-mcp"],
      "env": {
        "LEMON_CAKE_BUYER_JWT": "eyJhbGci..."
      }
    }
  }
}

Tools provided

| Tool | Description | |---|---| | fetch_url | Pay-per-call HTTP GET — any public API | | check_balance | Show remaining USDC balance | | set_spend_limit | Cap total spend for this session | | kill_switch | Halt all further charges immediately |

For MCP server developers

Want to add pay-per-call billing to your own MCP server? Use @lemon-cake/mcp-sdk:

npm install @lemon-cake/mcp-sdk

const lc = createLemonCakeSDK({ sellerKey: process.env.LEMONCAKE_SELLER_KEY });
execute: lc.charge({ price: 0.05 })(yourHandler)

License

MIT — LemonCake