ShopperProof
Run audit

Agent commerce protocols

UCP vs ACP vs AP2 vs MCP

A merchant-readable comparison of the agent-commerce protocols shaping AI shopping.

Updated June 6, 2026 · 10 min

Short answer

UCP, ACP, AP2, and MCP solve different parts of agent commerce. Merchants should understand them, but still test whether real shopper scenarios succeed.

  • UCP exposes commerce capabilities.
  • MCP connects agents to commerce tools.
  • ACP supports agentic checkout patterns.
  • AP2 focuses on payment authorization evidence.

How to use the protocols

Treat protocols as testable surfaces. Validate that they exist, then compare their claims to storefront evidence and run real scenarios.

  • Check discovery.
  • Check capability consistency.
  • Check product and policy evidence.
  • Check handoff confidence.

Turn this into a real scenario report

Run an audit to see transcripts, competitor outcomes, evidence gaps, and rerun recommendations for your own store.

Run a shopper audit