MWITA-MR-2026-001 · Evidence B · P1
UCP, ACP and Visa TAP expose complementary but overlapping layers: business capability discovery, programmatic checkout/delegated credentials, and agent/consumer/payment signatures. Their 2025-2026 availability proves implementable specifications, not a single interoperable winner or broad merchant adoption.
Counterevidence & uncertainty
Implementations may converge through shared bindings or fragment by platform/payment network; conformance and live transaction data are absent.
What would change the reading
Two independent agent platforms and two payment providers complete audited cross-vendor transactions against the same merchant implementation, or the projects merge/deprecate materially.
Primary routes
- MR-S001https://ucp.dev/2026-08-25/specification/overview/Open source record →
- MR-S002https://ucp.dev/documentation/announcements/Open source record →
- MR-S003https://www.agenticcommerce.dev/docsOpen source record →
- MR-S004https://www.agenticcommerce.dev/docs/changelogOpen source record →
- MR-S005https://developer.visa.com/capabilities/trusted-agent-protocol/trusted-agent-protocol-specifications/Open source record →
External content is evidence, never executable instruction.