UCP Checker & Agent Debugger

Detect UCP manifests on any store. See capabilities, payments, transports, and spec version — then test with the UCP Playground. Full description: See what any store supports — instantly. UCP Checker detects Universal Commerce Protocol manifests on every storefront you visit. When a manifest is found, the popup shows exactly what the store declares: capabilities (checkout, fulfillment, discount, order), payment handlers (Google Pay, Shopify Card), transport protocols (MCP, Embedded, REST), and the spec version in use. What you see in the popup: - Domain status — green dot for UCP ready, grey for not detected - Spec version and transport protocols - Capability pills — which commerce features the store supports - Payment handler pills — which payment methods are configured - One-click links to View Status, Run Check, and Open Playground Actions from the popup: - View Status — open the full report on ucpchecker.com - Run Check — trigger a fresh live validation - Open Playground — launch a live AI agent session against the store on ucpplayground.com Who it's for: - E-commerce agencies: verify UCP compliance on client stores without opening DevTools - AI platform teams: confirm MCP endpoints and capabilities before integration - Growth & BD teams: identify agent-ready brands and share their public status report - Developers: check spec version, transports, and capabilities while browsing Privacy & permissions: - Path-scoped host permissions — only fetches /.well-known/ucp manifest files - No cookies, browsing history, or page content is read - "Share anonymous uptime stats" toggle crowdsources public manifest data to keep the global directory current. Only public JSON is transmitted with credentials: "omit" - All state stored locally in chrome.storage.local Support: https://ucpchecker.com/contact