Using this reference
The tables help classification rather than procurement by component count. “Published” means documentation is accessible, not that adoption has been measured. “Draft” means change is explicitly expected. Even stable specifications may have services or integrations with limited access.
Eight fields for your own passport
Record purpose, version, supported functions, systems of record, actor identity, mandates and technical permissions, failure handling and one observed business case. Add ownership and date last checked. A useful passport explicitly states what does not yet work.
Commerce and collaboration
| Approach | Main purpose | Position in October 2026 | Verify before use |
|---|---|---|---|
| MCP | tools and context | specification 2026-07-28 | functions and permissions |
| A2A | agent tasks | published version 1.0.0 | completion and cancellation |
| UCP | Commerce capabilities | Release v2026-08-25 | Negotiated capabilities and versions |
| ACP | Commerce and checkout | Beta; specification 2026-04-17 | Channel admission and payment route |
| Personal Agent Protocol | personal agents at companies | Draft 0.1; checked 15 October 2026 | sessions and specific rights |
| PAP Operations | confirmed changes | optional draft extension | revision and recovery |
Payment and identity
| Approach | Main purpose | Position in October 2026 | Verify before use |
|---|---|---|---|
| AP2 | purchase and payment mandates | v0.2 documentation | roles and binding |
| Visa TAP | agent recognition | published network approach | participation and verification |
| Mastercard Agent Pay | agent payment infrastructure | commercially developed offering | market and partner access |
| Shared Payment Tokens | constrained credential use | provider-specific primitive | amount, time, recipient |
| PayPal Agent Ready | payment connectivity | commercial service | participation and coverage |
| PayPal Store Sync | catalogue and commerce connectivity | commercial service | functions per channel |
| x402 | web payments | open implementations | payment route and delivery |
| MPP | machine payments | published project | methods and operations |
Experience and interfaces
| Approach | Main purpose | Position in October 2026 | Verify before use |
|---|---|---|---|
| AXP | Product knowledge and experience | Lab prototype, snapshot 2026-01-13 | Support for embedded experience in the target channel |
| WebMCP | browser tools | proposed browser standard | supported environment |
| MCP Apps | interactive MCP interfaces | documented extension | host and security boundaries |
| AG-UI | agent events to interfaces | documented project | state and presentation |
| A2UI | described interfaces | open project; Lab PoC uses v0.8 | component catalogue and actual version |
Discovery and trust
| Approach | Main purpose | Position in October 2026 | Verify before use |
|---|---|---|---|
| ARD | resource discovery | young published specification | maintenance and trust |
| API Catalog | API discovery | IETF RFC 9727 | content and accessibility |
| PACT | personal-agent authority | new October 2026 approach | fit with existing access |
| ANP | open agent networking | published project | required trust model |
| ERC-8004 | registries and evidence | draft | value of blockchain use |
Primary sources: [S28–S53, S62, S63, S67–S69, S94–S98, S108]. Responsibilities overlap; identity and authorisation cut across several functions.
Other connections worth following
Further models for agent networking are developing alongside these approaches. ANP investigates open agent communication. The ERC-8004 draft addresses blockchain-based registries for agent identity, reputation and validation. Such approaches become relevant to a business when they help it find or assess suitable partners. [S68, S69]
The sources in the compact protocol passport provide a way to follow these developments. Your own planning can stay close to the purchase: what should customers be able to delegate, where do they want to participate, and which connection brings the two together?