Protocols | PairRail Atlas

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

Hit a public endpoint and inspect the payload an agent receives from PairRail Atlas. Adapters can change as protocols version. The catalog does not. Governance and quote authority live on Product. Settlement stays on your Stripe, Dodo, or signed webhook.

MCP

Model Context Protocol

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

Primary surface: POST /mcp?sellerId={sellerId}
Plan gate: Included on Sandbox with watermark. Pro removes the watermark.
Agent contract: Governed tools only. Published authority. No invented totals. Retryable errors say whether to revise, poll, or back off.
Gateway recipe: Point your MCP gateway (e.g. MintMCP) at this seller MCP URL. Browse is public; quotes require an approved machine key.
Watch for: Sandbox responses are marked non-production. Demo lab uses sellerId=northstar-compute.

UCP

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.
Agent contract: Discover seller identity, catalog feed, and published quote authority. Quotes stay indicative.

A2A

Agent2Agent card

Machine-readable capability descriptor with commercial boundaries.

Primary surface: GET /a2a?sellerId={sellerId}
Plan gate: Pro and Enterprise production presence.
Agent contract: Capability discovery and non-binding commercial edges.
Use when: Peer agents need a card before deeper catalog reads.

UAP

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.
Agent contract: Network-style discovery mapped from your governed catalog.
Use when: Agents participate in open-network commerce grids.

ACP

Agentic Commerce Protocol

Agent checkout parameters with published quote authority and policy fences.

Primary surface: GET /protocols/acp?sellerId={sellerId}
Plan gate: Pro and Enterprise.
Agent contract: Price and catalog discovery stay public. Quote requests map to Atlas quote authority; exceptions escalate to deal desk.
Use when: Buying agents need checkout-shaped commerce endpoints on your catalog.

Need raw HTTP schemas? That is API documentation, not a sixth commerce rail: OpenAPI reference. The UCP product feed is listed under UCP above.

AP2 next: verify the mandate, then settle on your rails

Google’s Agent Payments Protocol (AP2) is how a buying agent presents a signed payment mandate. Atlas will add AP2 verify on execute so we can check that mandate and settle through your merchant account or webhook. Stripe’s Machine Payments Protocol (MPP) and HTTP 402 / x402 follow on the same path. PairRail is not merchant of record.

Same catalog. Different rail access.

Sandbox One rehearsal rail · watermarked

Validate discovery and quote tools without putting production trust on the wire.

Pro Production rails · live

Full production presence without sandbox watermark. You approve which machines can act, set quote and spend limits, and rotate or revoke access anytime.

Enterprise Dedicated capacity · controls

Custom rate limits, private networking, and contracted SLA on the same protocol set, scoped per contract.

Tier depth lives on Product. Dollars and limits live on Pricing.

What every rail promises

Published catalog truth only. No scraped marketing pages.

Seller-approved machine access for action. Discovery can stay public; acting requires your say.

Indicative quotes until execute. Binding settlement runs on your billing rails on Pro; Sandbox rehearses with Mock mode. PairRail does not hold customer funds.

Turnkey adapters for your payment rails or signed webhooks. Import Stripe products into a draft. Your payment stack receives standard API calls, not protocol negotiation.

Published quote authority and credential velocity. Errors include a retry contract.

Fail closed on exceptions. Humans own the deal desk.

One catalog projection. You do not maintain five price books.