Protocols

Every major agent protocol, served from one catalog you control.

Every protocol gets the same deterministic prices and your approval thresholds from one governed catalog. Adapters change as protocols version. The catalog does not. Hit a public endpoint below and inspect exactly what an agent receives.

Open the lab Read the docs

One catalog

Fernwell AI

catalog v18

Sample seller

Tools any MCP client can call. /mcp
Business profile and product feed. /.well-known/ucp
Commerce endpoints inside your quote authority. /protocols/acp
A capability card before deeper reads. /a2a
Open-network commerce grids, no second price book. /protocols/uap

Pick a protocol. Inspect the payload.

These endpoints are public and serve a demo catalog. Yours appear on the protocols your plan unlocks.

MCP · sandbox

Model Context Protocol

Tool surface for agents to discover offers, validate parameters and request quotes.

Primary surface: POST /mcp?sellerId={sellerId}
Plan gate: Live on Sandbox for discovery and indicative pricing, with quotes marked as a rehearsal; Pro sends live quotes. The lab uses sellerId=northstar-compute.
Tools: Public: catalog_browse, catalog_discover, pricing_calculate, readiness_inspect, request_catalog_access. quote_request needs an approved machine key.
Transport: JSON-RPC over HTTP. Point any MCP client or gateway (e.g. MintMCP) at this URL.

UCP · profile

Universal Commerce Protocol

Business profile, product feed and commerce endpoints for ecosystem agents.

Primary surface: GET /.well-known/ucp?sellerId={sellerId}
Product feed: GET /protocols/ucp/products?sellerId={sellerId} (part of UCP, not a separate rail)
Plan gate: Pro and Enterprise. Sandbox does not expose this rail.
Discovery: Seller identity, the product feed and your published quote authority, from the /.well-known path agents check first.

ACP · commerce

Agentic Commerce Protocol

Commerce endpoints that carry your published quote authority and policy fences.

Primary surface: GET /protocols/acp?sellerId={sellerId}
Plan gate: Pro and Enterprise.
Actions: GET returns the descriptor. POST prices by default; quote needs an approved machine key, and execute also needs the quote:execute scope.
Use when: Buyer agents expect ACP commerce endpoints on your catalog.

A2A · card

Agent2Agent card

Machine-readable capability descriptor with commercial boundaries.

Primary surface: GET /a2a?sellerId={sellerId}
Plan gate: Pro and Enterprise production presence.
Actions: GET returns the A2A v1.0 agent card, also at /.well-known/agent-card.json. POST takes JSON-RPC SendMessage; quotes need an approved machine key.
Use when: Peer agents need a card before deeper catalog reads.

UAP · network

India UAP & Beckn

Compatibility with Unified Agent Protocol and open-network commerce grids.

Primary surface: GET /protocols/uap?sellerId={sellerId}
Plan gate: Pro and Enterprise.
Actions: Beckn-style verbs: select prices, init quotes and confirm executes. init and confirm need an approved machine key. /protocols/beckn is an alias.
Use when: Agents participate in open-network commerce grids.

Need raw HTTP schemas? That is API documentation, not a sixth protocol: OpenAPI reference (opens in new tab). The UCP product feed is listed under UCP above.

Every protocol returns the same quote.

Published truth onlyEvery number comes from the catalog version you published, never from scraped pages or invented totals.
Same rules on every protocolDiscovery is public. Quotes need a key you approved, and the same approval threshold applies whichever protocol asks. How quote authority works

Fernwell AI quote, 400M tokens

Sample seller

$1,200.00

400M tokens × $3 per 1M = $1,200.00

Same quote on every protocol

Protocol versions and changes

The spec each adapter follows today, and what has changed. ACP and UAP / Beckn are PairRail mappings, not full implementations. Every endpoint takes ?sellerId= with the seller’s slug. Agents can read the versions at /protocols/changelog.json and every change in the changelog.

Protocol	Version	Endpoint	Notes
MCP	2026-07-28	/mcp	Stateless 2026-07-28 requests, and legacy clients (2025-11-25 back to 2024-11-05) through initialize. A tool that fails returns a result with isError.
UCP	2026-08-25	/.well-known/ucp	Profile, product feed, catalog search and lookup. Checkout and reading the calling platform's profile are not built yet.
ACP	2026-04-17	/protocols/acp	ACP line items for each public offer, in a PairRail descriptor, without the ACP checkout session API.
A2A	1.0	/.well-known/agent-card.json	Agent card and JSON-RPC SendMessage. Streaming, push notifications and stored tasks are not offered.
Web Bot Auth	IETF draft-00	Quote and access requests	Signed quote and access requests are checked against the agent's published keys and shown to the seller. Record-only: never blocks a request.
UAP / Beckn	PairRail 2026.1	/protocols/uap	PairRail profile rather than a published UAP or Beckn schema, without Beckn context or on_* callbacks.

Recent changes

Full changelog

Next on the roadmap: AP2, MPP and x402

Agents are starting to pay through these standards. Atlas will check the buyer’s payment before an approved quote goes through. The money goes from buyer to seller, never through PairRail.

Agent Payments Protocol
Would check the buyer’s signed AP2 payment mandate before an approved quote goes to your billing system.
Machine Payments Protocol
Would let a buyer’s agent pay for an approved quote over MPP, paid into your own Stripe account.
x402
Atlas can already describe a price as an x402 payment request. It stays off until payment checks and replay protection are built.

Inspect a protocol, then publish a catalog

Use the lab above, then score your pricing for free or onboard the catalog when you are ready to publish.

Score your pricing, free Onboard a catalog