# Universal Commerce Protocol (UCP)

> The Universal Commerce Protocol (UCP) is a solution for enabling gen AI agents to make payments on behalf of users, safely, securely, and in a decentralized and privacy protecting manner. This protocol is a part of the broader ecosystem, which includes agentic protocols like A2A and MCP, and encompasses the global nature of payments.


This is the documentation directory for the Universal Commerce Protocol
(UCP), an open standard that enables gen AI agents to safely, securely,
and privately execute commerce actions (i.e., discovering, buying) on
behalf of users.
### Technical Specification Indices (llms.txt)
For raw, LLM-optimized indices of our versioned technical
specifications:
- [Latest Stable UCP
  Specification Index](https://ucp.dev/latest/llms.txt):
  Standardized specifications for production deployments.
- [UCP Specification Index
  (2026-04-08)](https://ucp.dev/2026-04-08/llms.txt):
  Stable spec release version 2026-04-08.
- [UCP Specification Index
  (2026-01-23)](https://ucp.dev/2026-01-23/llms.txt):
  Stable spec release version 2026-01-23.
- [UCP Specification Index
  (2026-01-11)](https://ucp.dev/2026-01-11/llms.txt):
  Stable spec release version 2026-01-11.


## Overview

- [Home](http://ucp.dev/index.md): High-level architecture, core value propositions, and structural capabilities of the Universal Commerce Protocol (UCP) as a common language for commerce agents.
- [Core Concepts](http://ucp.dev/documentation/core-concepts/index.md): Fundamental UCP abstractions, including the decoupled separation of capabilities, extensions, services, and the decentralized protocol negotiation model.
- [UCP and AP2](http://ucp.dev/documentation/ucp-and-ap2/index.md): Integration patterns with the Agent Payments Protocol (AP2) to facilitate secure, agent-mediated checkout commitments and cryptographically signed mandates.
- [Roadmap](http://ucp.dev/documentation/roadmap/index.md): Future development and planned capabilities of UCP.
- [Schema Authoring](http://ucp.dev/documentation/schema-authoring/index.md): Comprehensive guidelines and JSON Schema design conventions when authoring or extending UCP schemas, including strict versioning and registry patterns.
- [Versioning](http://ucp.dev/versioning/index.md): UCP's strict date-based versioning policy (YYYY-MM-DD) and compatibility guidelines for managing breaking changes and release branches.
- [Announcements](http://ucp.dev/documentation/announcements/index.md): General announcements, release notes, and community updates for the Universal Commerce Protocol.