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Agentic Commerce Protocol (ACP)

The Agentic Commerce Protocol is an open checkout specification that lets buyers, AI agents, and sellers transact through APIs. Co-developed by Stripe and OpenAI in September 2025 as the reference protocol for agent-initiated commerce, and published at github.com/agentic-commerce-protocol.

ACP defines the wire-level shape of an agentic checkout: the agent, acting on behalf of a buyer, calls seller-side ACP endpoints to verify inventory, commit a checkout state, and submit a payment token — keeping the buyer's credentials vaulted at the payment provider and exposing only scoped, agent-usable payment metadata to the agent.

Release history (through 2026-03-12)

Per the 2026-03-12 Stripe retrospective, ACP shipped four releases in its first six months, each adding a major capability:

1. Payment handlers — RFC rfc.payment_handlers. Mechanism for seller-side acceptance of agent-submitted payment instruments.
2. Scoped tokens — RFC rfc.seller_backed_payment_handler. Tokens scoped to the specific cart / buyer-intent so the seller-backed handler can verify scope before authorising.
3. Extensions mechanism — RFC rfc.extensions. Versioned opt-in extension points for post-core capabilities. First extension: discounts — RFC rfc.discount_extension.
4. Built-in buyer auth — in-protocol mechanism for the agent to pass buyer-authentication evidence to the seller (specific RFC not cited in the Stripe post).
5. Native MCP transport — PR #139. ACP now supports carriage over Model Context Protocol, bridging agent-tool-discovery and agentic-commerce transport into one mechanism.

Position on this wiki

ACP is one of at least two competing agentic-commerce protocols: Google is developing UCP (Universal Commerce Protocol) as a parallel standard. Per the 2026-03-12 Stripe post, "sellers can't afford to rebuild their stack every time a protocol changes" — Stripe positions the Agentic Commerce Suite as a protocol-agnostic commerce layer that absorbs the churn.

Scope boundary

ACP is the checkout protocol for agent-initiated human-buyer transactions ("a checkout session with shipping, loyalty, and a human confirmation step"). It is not designed for agent-to-agent per-request payments — those use a different shape, typically HTTP 402 + x402 + stablecoin settlement (see concepts/machine-payment).

Seen in

• sources/2026-03-12-stripe-10-things-we-learned-building-for-the-first-generation-of-agentic-commerce — canonical Stripe retrospective on the first six months of production ACP deployments with URBN, Etsy, Coach, Kate Spade, and Ashley Furniture. The four-release roadmap and the native-MCP-transport milestone are disclosed here.

Related

• systems/stripe-agentic-commerce-suite — Stripe's protocol-agnostic commerce product that implements ACP (and Google UCP) under a single seller-facing abstraction.
• systems/model-context-protocol — transport layer ACP supports natively as of PR #139.
• systems/x402-protocol — parallel open standard for machine payments; ACP is for human-buyer checkout, x402 for agent-to-API per-request charges.
• concepts/shared-payment-token — Stripe's SPT primitive, implemented inside the ACP scoped-tokens RFC.
• concepts/agentic-commerce — the broader commerce category ACP serves.
• companies/stripe — ACP co-author (with OpenAI).