Every UCP store picks how it speaks to agents: a JSON-RPC MCP server, OpenAPI REST endpoints, an A2A Agent Card, an embedded checkout surface, or a plain redirect hand-off. Open any transport to see exactly what it is, why it matters for agentic commerce, and how the validator verifies it.
Model Context Protocol: JSON-RPC tool calls agents use to search, cart, and check out.
OpenAPI REST endpoints with UCP-Agent and Idempotency-Key headers.
Agent-to-Agent: discovery via an Agent Card for agent-native interactions.
Embedded Checkout Protocol: postMessage handshake + CSP frame-ancestors.
Hand-off to a hosted checkout URL when programmatic checkout is unavailable.
The validator reads a store's UCP manifest, checks which transports are declared in its service bindings, and probes the advertised endpoints to confirm they respond. Run a free scan on any store to see which transports it exposes today.