UCP — Universal Commerce Protocol

Google & Shopify's capability-based commerce protocol with a well-known manifest.

Google & Shopify's capability-based commerce protocol. The agent points at a UCP manifest (/.well-known/ucp) listing the capabilities it supports (checkout, discount, fulfillment, identity linking, order management, token exchange) and the transports it speaks (A2A, MCP, REST, embedded).

Standardised request shape for agent-driven checkout: AstraSync verifies the agent and forwards the envelope under policy.

You declare: manifest URL, version, capabilities, transports, custom extensions.

PDLSS pre-fill: checkout / payment capabilities add financial_transaction purpose; fulfillment adds execute_action; manifest domain added to counterparties.

{
  "protocols": ["a2a", "ucp"],
  "ucp": {
    "manifestUrl": "https://shop.example.com/.well-known/ucp",
    "version": "1.0",
    "capabilities": [
      "dev.ucp.shopping.checkout",
      "dev.ucp.shopping.fulfillment"
    ],
    "transports": ["a2a", "rest"]
  }
}