# A3 — UCP (Universal Commerce Protocol)

> A3 turns any website into a UCP-compliant commerce endpoint — so agents and aggregators can transact without waiting for a bespoke partner API.

**URL:** https://athree.dev/ucp  
**Canonical markdown:** https://athree.dev/ucp.md

## Summary

The Universal Commerce Protocol (UCP) is a way for agentic clients to discover and call commerce capabilities. A3 learns booking / checkout flows from live merchant websites and exposes them as UCP-compliant (and/or REST) endpoints.

That closes the “API gap”: aggregators get inventory they can book; suppliers get distribution without building and maintaining a public API first.

## Why it matters

- Most commerce still runs on websites, not partner APIs
- Always-on LLM checkout agents are expensive and hard to SLA
- A3 learns once, runs as code, and can heal when the site changes

## Related use case

- E-commerce automation: https://athree.dev/use-cases/e-commerce.md
- Overview: https://athree.dev/index.html.md