ACP, UCP, and the protocols letting AI agents buy from your store
Two open standards now define how AI assistants discover and transact with merchants. Here’s what each one does and what to prepare — without the hype.
Published August 27, 2026 · By the WorkDaddy team
The Agentic Commerce Protocol (ACP) is an open standard, co-developed by OpenAI and Stripe and released in September 2025, that defines how AI agents and merchants exchange product data and complete purchases. Google’s Universal Commerce Protocol (UCP), introduced in early 2026 with partners including Shopify, Target, and Walmart, aims at the same problem across the whole shopping journey — discovery, checkout, and post-purchase. Neither requires most merchants to write code today, because platforms like Shopify implement them on merchants’ behalf. But understanding what the protocols cover explains where AI shopping is headed and what data you need to get right.
Key takeaways
ACP (OpenAI + Stripe, September 2025) and UCP (Google, early 2026) are open standards for agent-to-merchant commerce
ACP today centers on ChatGPT product discovery; in-chat Instant Checkout was retired in March 2026
UCP is scoped wider — discovery through checkout and post-purchase — and interoperates with MCP and A2A
Platforms implement the protocols; merchants win or lose on the quality of the data flowing through them
Feed hygiene and monitoring how assistants represent you are ongoing work, not a one-time setup
Why protocols exist at all
An AI assistant recommending products needs three things from a merchant: trustworthy product data, a way to check price and availability in real time, and a sanctioned path to purchase. Without standards, every assistant would need a custom integration with every merchant — which doesn’t scale past a handful of big retailers. Protocols solve this the way RSS solved feeds or OAuth solved login: one published specification that any agent and any commerce platform can implement once. That’s why the major players moved quickly to publish open standards rather than keep integrations proprietary — the assistant with the most connected merchants wins, and open specs recruit merchants fastest.
What the Agentic Commerce Protocol (ACP) is
ACP is a specification for agent-to-merchant commerce, released under an open-source license in September 2025 and maintained by OpenAI and Stripe, with PayPal later joining as a payment provider. It originally powered Instant Checkout in ChatGPT — completing purchases inside the chat — but OpenAI retired that flow in March 2026 after limited merchant adoption, and refocused ACP on product discovery: merchants publish structured product feeds that ChatGPT can search and surface, while checkout completes on the merchant’s own site. The spec has continued to evolve through 2026, with published updates adding support for carts, order management, feeds, and compatibility with the Model Context Protocol (MCP).
Co-developed by OpenAI and Stripe; released as an open standard in September 2025
Powers product discovery in ChatGPT via structured merchant feeds
In-chat Instant Checkout was retired in March 2026; purchases now complete on merchant sites
Spec updates through 2026 added carts, orders, and MCP compatibility
What Google’s Universal Commerce Protocol (UCP) is
UCP is Google’s open standard for agentic shopping, introduced in early 2026 and developed with retail and payments partners including Shopify, Etsy, Wayfair, Target, Walmart, Mastercard, and Visa. Where ACP as deployed today centers on discovery feeding into merchant-site checkout, UCP is scoped more broadly: it aims to cover the full journey from discovery through agent-assisted checkout on Google surfaces to post-purchase support, and it is designed to interoperate with existing standards like MCP and the Agent2Agent protocol. Google has also published related work on agent-led payments. For merchants the immediate touchpoint is familiar — UCP builds on Merchant Center product data.
How the pieces fit together in practice
It helps to see the flow end to end. A shopper asks an assistant for a product. The assistant queries catalogs it can read — via ACP-style feeds, UCP, platform integrations like Shopify’s Catalog, or plain web crawling. It synthesizes a shortlist, drawing on product data, reviews, and content about the products from across the web. The shopper picks one, and the assistant hands off to the merchant’s checkout, or on some surfaces completes the purchase through the protocol’s checkout flow. Every step depends on the quality of what you publish: sparse or stale product data means you lose at the query step, before any human ever sees your brand.
What merchants should actually do about ACP and UCP
For most merchants the honest answer is: don’t build protocol integrations yourself — your platform will. Shopify already surfaces eligible merchants’ products in ChatGPT and is a UCP partner; other major platforms are following. Your job is to make sure what flows through those pipes is accurate and complete, because the protocols transmit whatever you have. Audit your product data the way an agent reads it: titles that say what the product is, complete attributes, real-time price and stock, honest shipping and returns policies, and reviews. Treat feed hygiene as an ongoing discipline, not a launch task.
Confirm your platform’s agentic integrations are enabled for your store
Fix product titles, descriptions, and attributes so they’re unambiguous out of context
Keep price, availability, and shipping data accurate — agents penalize surprises at handoff
Add structured data (Product, Offer, Review schema) so non-feed surfaces can read you too
Monitor whether assistants actually surface and describe your products correctly
The bottom line for store owners
Protocols are plumbing, and plumbing rewards whoever has clean water. ACP and UCP will keep changing — versions, partners, and checkout models have all shifted within a single year — so betting on any one implementation detail is risky, while betting on data quality is safe under every scenario. The durable work is keeping your catalog, content, and site continuously agent-readable and monitoring how assistants represent you. That monitoring and upkeep is exactly the kind of recurring, detail-heavy work that merchant-side agents handle well; WorkDaddy’s Visibility agent, for example, tracks how your store shows up across AI surfaces and proposes fixes for you to review.
Frequently asked questions
What is the Agentic Commerce Protocol (ACP)?
ACP is an open standard co-developed by OpenAI and Stripe, released in September 2025, that defines how AI agents and merchants exchange product data and complete transactions. It initially powered Instant Checkout inside ChatGPT; after OpenAI retired that flow in March 2026, ACP’s main deployed role became product discovery — merchants publish structured feeds that ChatGPT surfaces in shopping conversations, with checkout completing on the merchant’s own site. The specification is openly published and has continued to evolve through 2026.
How is UCP different from ACP?
Google’s Universal Commerce Protocol is scoped more broadly than ACP as currently deployed. UCP aims to cover the full shopping journey — discovery, agent-assisted checkout on Google surfaces, and post-purchase support — and was developed with partners including Shopify, Target, Walmart, and major payment networks. It is designed to work alongside existing standards like MCP and Agent2Agent. ACP, maintained by OpenAI and Stripe, today primarily powers product discovery in ChatGPT with checkout handed off to merchants.
Do I need to integrate ACP or UCP myself?
Almost certainly not. Commerce platforms implement these protocols on merchants’ behalf — Shopify, for example, made eligible merchants’ products discoverable in ChatGPT by default in March 2026, with no separate app or integration required, and is a UCP launch partner. Your effective integration work is data work: complete product attributes, accurate real-time pricing and inventory, clear policies, and structured data on your pages. Custom protocol builds only make sense for large or headless merchants with engineering teams.
Will AI agents check out directly on my store?
The direction of travel suggests yes, but as of mid-2026 the common pattern is assisted handoff: the agent recommends, then the shopper completes checkout on your site. In-chat checkout has been tried and pulled back once already — OpenAI retired Instant Checkout in March 2026 — while Google’s UCP supports agent-led checkout on some of its surfaces. Prepare for both by keeping checkout fast and friction-light and your pricing and stock data accurate, which pays off under either model.
Keep reading
What is agentic commerce?
The full picture the protocols fit into, on both the buyer and merchant side.
Make your store agent-ready
The data and content work that determines what flows through ACP and UCP.
Agentic commerce for Shopify
How Shopify implements these protocols for its merchants.
AI search visibility
Monitor and improve how AI assistants surface your store.
Put the team to work on your store
Connect your storefront, analytics, and email stack, set a goal, and let the agents run the work end to end. Start on the free plan with your own model key.