{"id":"d2d267a6-fb36-43c7-9306-7f49716dd2ab","task":"Implement the Universal Commerce Protocol's /.well-known/ucp discovery manifest, including the March 2026 Cart and Product Discovery capability additions, so any UCP-compliant agent can dynamically discover a merchant's supported commerce actions","domain":"developers.google.com","steps":["Publish a JSON manifest at /.well-known/ucp listing the capabilities your storefront supports -- at minimum, the checkout capability, and, since the March 2026 update, Cart (multi-item checkout sessions) and Product Discovery & Catalog (real-time inventory, variants, pricing)","For the Product Discovery & Catalog capability, wire the manifest's advertised endpoint to your live inventory and pricing system so agents querying it get current data rather than a stale snapshot","For the Cart capability, support building and modifying a multi-item cart across multiple agent turns rather than only a single-item purchase flow","Ensure the manifest also declares your supported payment configurations so an agent can determine compatible payment paths without a separate out-of-band integration step","Register or simplify onboarding through Merchant Center if using Google's UCP tooling, per the March 2026 simplification of that onboarding path","Test discovery end to end: have a UCP-compliant agent fetch /.well-known/ucp cold and confirm it can enumerate and use each declared capability without hardcoded knowledge of your site"],"gotchas":["Before March 2026, UCP was effectively a single-item checkout spec -- documentation, blog posts, or integrations written before that date may describe a narrower protocol than what's now available, so verify against current capability lists","The manifest only advertises capabilities; each declared capability still needs a working backing implementation (e.g. an actual live-catalog query endpoint) or agents will discover a capability that fails when invoked","This is Google's protocol and distinct from OpenAI/Stripe's ACP -- a merchant targeting both ecosystems needs separate discovery artifacts (/.well-known/ucp vs the ACP Feed/checkout endpoints), not a single shared manifest"],"contributor":"waymark-seed","created":"2026-07-08T17:34:57.823Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/d2d267a6-fb36-43c7-9306-7f49716dd2ab"}