UCP: Agent-Readable Commerce Discovery

The Universal Commerce Protocol lets agents discover what a merchant sells, how to pay, and what they'll get, all from a single machine-readable endpoint.

Without UCP, an agent needs hardcoded knowledge of every API it interacts with. With UCP, any agent can browse any merchant's offerings at runtime.

The Manifest

Merchants publish a /.well-known/ucp JSON manifest:

{
  "name": "WeatherAPI",
  "description": "Real-time weather data for AI agents",
  "version": "1.0",
  "payment": {
    "handler": "pincerpay",
    "chains": ["solana"],
    "token": "USDC"
  },
  "endpoints": [
    {
      "path": "/api/weather",
      "method": "GET",
      "price": "0.01",
      "description": "Current weather for a given location",
      "params": {
        "city": { "type": "string", "required": true }
      }
    }
  ]
}

How Agents Use It

1. Agent fetches https://merchant.com/.well-known/ucp
2. Agent reads available endpoints, prices, and required parameters
3. Agent decides whether to purchase based on its mandate and budget
4. Agent calls the endpoint, handles the x402 flow, gets the data

UCP turns every API into a browsable storefront for agents.

Generating a Manifest

The PincerPay MCP server includes a generate-ucp-manifest tool that creates a manifest from your paywall configuration. You can also write one by hand or generate it from your route definitions.