Agent Commerce Signals

Agent commerce signals are protocols and metadata patterns that help AI agents discover products, authenticate users, pay, and complete transactions safely.

This space is moving quickly. Treat individual acronyms as evolving protocol signals, not as universal requirements for every product website.

Key Terms

• x402: a payment protocol that uses HTTP 402 Payment Required semantics for machine-to-machine payments.
• ACP: Agentic Commerce Protocol, an open specification for programmatic checkout between buyers, AI agents, and sellers.
• UCP: Universal Commerce Protocol, a broader commerce lifecycle and capability-negotiation specification covering catalog, cart, identity, checkout, and orders.
• AP2: Agent Payments Protocol, a Google-led protocol for agentic payments and user authorization.
• MPP: Machine Payments Protocol, designed by Tempo and Stripe for machine-to-machine payments across APIs, tools, and HTTP-addressable resources.

What Product Websites Should Do First

Before adopting any payment protocol, make the basics clean:

• Product pages are crawlable
• Product structured data is valid
• Pricing, availability, shipping, and return policy are visible
• Public APIs are documented
• Authentication and consent boundaries are explicit
• Checkout policies are clear to humans and agents

Related Concepts

• API Catalog SEO
• Auth.md and OAuth Metadata
• A2A Agent Card
• Product schema checklist

Official Resources

• x402 protocol
• Agentic Commerce Protocol
• Universal Commerce Protocol
• Machine Payments Protocol
• Agent Payments Protocol
• OpenAPI Specification