Protocol Changelog
A complete history of Agent Commerce Protocol versions and changes.
v2.0
CurrentMarch 2026Negotiation, Transactions & Trust
- Added negotiation protocol with typed offers, counter-offers, and state machine
- Added transaction protocol with full lifecycle management
- Added escrow support for conditional purchases with timed release
- Added trust score system with 7 components and tier classification
- Added 30+ webhook event types for real-time notifications
- Added HMAC signature verification for webhook security
- Added agent-exclusive offers and bundle endpoints
- Added price hold mechanism for time-limited pricing
- Added feedback endpoint for agent quality signals
- Added degradation headers for partial/stale data indication
- Enhanced product card format with comparison highlights and brand voice summary
- Enhanced query protocol with review and availability intents
- Improved error responses with detailed field-level validation
v1.0
September 2025Initial Release
- Introduced the Agent Commerce Protocol specification
- Added query protocol with search, recommend, compare, and detail intents
- Added AgentProductCard format for structured product representation
- Added discovery protocol with .well-known/acp.json
- Added API key authentication with public and secret key types
- Added rate limiting with tiered access
- Added standard error response format
- Added semantic versioning and backward compatibility rules