Protocol directory
Agentic commerce protocol directory
A maintained directory of the core protocols used around agentic commerce. The Atlas is not the primary specification for any protocol; use this page to understand the layer, role, maintainer, and status, then follow the official source for implementation details.
Machine-readable version: /data/protocols.json. Last checked:
2026-09-07.
| Protocol | Layer | Maintainer and status | Source | Atlas guide |
|---|---|---|---|---|
| ACP Agentic Commerce Protocol | Commerce semantics | OpenAI and Stripe (founding maintainers); MAINTAINERS.md also lists Meta beta | Official source | Read guide |
| UCP Universal Commerce Protocol | Commerce semantics | Governance Council (Google, Shopify, Stripe, plus two seats open for election) over per-domain Tech Councils: a 16-seat Shopping Tech Council (Google, Shopify, Amazon, Etsy, Meta, Microsoft, Salesforce, Stripe, Target, Wayfair), a Food Tech Council formed July 2026 (Google, Square, Toast, DoorDash, Uber Eats), and a Lodging Tech Council seated 11 August 2026 (Amadeus, Booking.com, Expedia, Google, Hilton, Marriott, Trip.com) launched | Official source | Read guide |
| AP2 Agent Payments Protocol | Payment authorization | FIDO Alliance (originated at Google) pre-production | Official source | Read guide |
| MCP Model Context Protocol | Discovery | Agentic AI Foundation, a directed fund under the Linux Foundation (originated at Anthropic; donated December 2025) widely adopted | Official source | Read guide |
| A2A Agent-to-Agent | Agent coordination | Agentic AI Foundation, a directed fund under the Linux Foundation (originated at Google; donated to the Linux Foundation in 2025 and moved into the Agentic AI Foundation on 17 August 2026) v1.0 | Official source | Read guide |
| x402 x402 | Settlement | x402 Foundation, under the Linux Foundation (originated at Coinbase) live | Official source | Read guide |
| MPP Machine Payments Protocol | Settlement | Tempo Labs and Stripe live | Official source | Read guide |
| LCP Legal Context Protocol | Legal context | Integra Ledger and the American Arbitration Association-International Centre for Dispute Resolution (AAA-ICDR), as Founding Maintainers draft | Official source | Read guide |
How to read the layers
- Discovery: how agents find tools, data, and capabilities.
- Commerce semantics: how shopping, cart, checkout, and post-purchase actions are represented.
- Payment authorization: how user intent and delegated authority are recorded.
- Settlement: how software pays for services, API calls, or other resources.
- Agent coordination: how agents communicate and delegate work to one another.
- Legal context: how the terms governing a transaction, and the route to recourse if it goes wrong, are published and proved.
Use boundaries
This directory is an orientation layer. It is useful for comparison, discovery, and citation, but implementation-critical decisions should be checked against the official source linked for each protocol.