Agent Commerce Protocol (ACP)

What is the Agent Commerce Protocol?

ACP addresses a specific and critical challenge in agentic commerce: how does an AI agent safely pay for something? When an AI purchasing agent identifies the right product from the right supplier, it needs a secure mechanism to complete the transaction, one that handles payment credentials, fraud prevention, order confirmation, and merchant settlement without exposing sensitive financial data. ACP, built on Stripe's payment infrastructure, provides exactly this.

The protocol was developed by OpenAI in partnership with Stripe, combining OpenAI's AI agent capabilities with Stripe's established payment processing infrastructure. This partnership is significant because Stripe already processes payments for millions of businesses globally. ACP leverages this existing network, meaning merchants who already use Stripe can enable agent-initiated purchases with relatively minimal additional integration work.

ACP focuses specifically on the transaction layer (checkout, payment, and order confirmation) rather than attempting to cover the full commerce lifecycle. Product discovery and evaluation are handled upstream by other protocols or the AI agent's own capabilities. This focused scope makes ACP complementary to broader protocols like UCP and data access protocols like MCP, rather than a direct competitor.

Why ACP Matters for B2B Businesses

For manufacturers and B2B suppliers, ACP is the third-priority protocol after UCP and MCP in the agentic commerce readiness sequence. Its importance stems from OpenAI's market position: ChatGPT, custom GPTs, and the broader OpenAI developer ecosystem represent a large and growing population of AI agents that businesses and consumers use for research, purchasing decisions, and increasingly, direct transactions.

The B2B implications of ACP are becoming clearer as enterprises build custom AI agents on OpenAI's platform for procurement and purchasing tasks. These agents need a way to complete purchases, and ACP provides the secure transaction mechanism. For suppliers targeting organisations that use OpenAI-powered procurement tools, ACP compatibility ensures that agent-identified purchases can be completed without falling back to manual ordering processes, which would negate many of the efficiency gains of agent-driven procurement.

The Stripe integration is particularly relevant for B2B businesses that already process payments through Stripe. These businesses have a natural advantage in ACP adoption because much of the required infrastructure (merchant accounts, payment processing, fraud detection) is already in place. The additional work involves exposing checkout capabilities through ACP endpoints and ensuring product data is structured for agent consumption. For businesses not yet on Stripe, ACP adoption requires a broader infrastructure decision that may be better deferred until after UCP and MCP readiness is established.

How ACP Works

ACP operates through a secure handoff between the AI agent and Stripe's payment infrastructure. When an agent is ready to complete a purchase, it initiates an ACP transaction by submitting order details (product identifiers, quantities, shipping information) to the merchant's ACP endpoint. The merchant's system validates the order against available inventory and pricing, then creates a Stripe payment session.

Payment credentials are handled through tokenisation, meaning the AI agent never has direct access to the buyer's payment card numbers or bank details. Instead, the buyer pre-authorises payment credentials that are stored as secure tokens within Stripe. When the agent initiates a purchase, it references these tokens rather than actual financial data. Stripe processes the payment using its standard fraud detection and verification systems, and the merchant receives confirmation through their existing Stripe integration.

Once payment is confirmed, ACP returns an order confirmation to the AI agent, including order identifiers, expected delivery timelines, and any relevant tracking information. The agent can then monitor order status and report back to the buyer. For B2B transactions involving purchase orders, credit terms, or invoice-based payment, ACP's capabilities are still evolving; the current strength is in card-based and pre-authorised transactions. Businesses with complex B2B payment requirements may find that UCP offers more flexibility for these scenarios while ACP handles the subset of transactions suited to Stripe's payment model.

Key Takeaways

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