Evidence
The public source register.
A versioned list of primary documents and the exact proposition each one can establish.
This register does not measure source popularity. It documents evidentiary purpose. Register data is available as JSON under CC BY 4.0 to support reuse, audits and citations by human or automated systems.
Checked on 2026-08-12
JSON version of the register-
01
Primary source / specification
UCP Official Specification
Universal Commerce Protocol
Normative specification, dated release, capability discovery and negotiation.
Open source -
02
Primary source / governance
UCP Versioning
Universal Commerce Protocol
Official versioning, release branch and breaking-change rules.
Open source -
03
Primary source / specification
Universal-Commerce-Protocol/ucp
GitHub
Public repository for the specification, releases, roadmap and contributions.
Open source -
04
Primary source / implementation
Universal-Commerce-Protocol/conformance
GitHub
Official conformance tests maintained by the UCP project.
Open source -
05
Primary source / implementation
Universal-Commerce-Protocol/ucp-schema
GitHub
Public schema validator maintained by the UCP organization.
Open source -
06
Primary source / implementation
Under the Hood: Universal Commerce Protocol
Google Developers Blog
Technical overview and announced co-developer and supporter list.
Open source -
07
Primary source / implementation
Getting started with Universal Commerce Protocol on Google
Google for Developers
Google merchant guide, checkout options and Merchant of Record status.
Open source -
08
Primary source / implementation
Universal Commerce Protocol
Shopify
Shopify overview of primitives, operations, extensions, payments and transports.
Open source -
09
Primary source / implementation
Building the Universal Commerce Protocol
Shopify Engineering
Protocol architecture and confirmation of co-development with Google.
Open source -
10
Primary source / governance
Announcing new Tech Council members
UCP GitHub Discussions
Announced Tech Council membership as of April 24, 2026.
Open source -
11
Primary source / search
Optimizing for generative AI features on Google Search
Google Search Central
Foundational SEO, original content and clear structure remain the documented levers.
Open source -
12
Primary source / search
Overview of OpenAI crawlers
OpenAI Developers
Distinct roles for OAI-SearchBot, GPTBot and ChatGPT-User.
Open source -
13
Primary source / search
Does Anthropic crawl data from the web?
Claude Help Center
Distinct roles for ClaudeBot, Claude-SearchBot and Claude-User.
Open source -
14
Primary source / search
Perplexity Crawlers
Perplexity Docs
Distinct roles for PerplexityBot and Perplexity-User.
Open source