Agentic Commerce

Agentic commerce describes AI agents completing purchases on behalf of users: researching options, selecting a product, and processing payment, with the user authorising rather than manually executing each step. The commercial and technical infrastructure to support this is being built across the industry. The gap between that infrastructure and actual agent-completed transaction volume is currently significant. This article distinguishes what is confirmed, what is operational but early-stage, and what remains speculative.

What is the Universal Commerce Protocol?

The Universal Commerce Protocol (UCP) is an open standard for agentic commerce, developed by Google in collaboration with Shopify, Etsy, Wayfair, Target, and Walmart, and endorsed by more than 20 partners including Adyen, American Express, Best Buy, Flipkart, Macy’s, Mastercard, Stripe, The Home Depot, Visa, and Zalando.¹ Sundar Pichai announced it at the National Retail Federation conference on 11 January 2026, describing it as “open, agnostic, built together with industry leaders” and available from that day.² It defines a common language for commerce interactions between AI agents, merchants, and payment providers: product discovery, capability negotiation, checkout, and post-purchase handoff.³¹ A UCP-enabled site advertises itself at /.well-known/ucp, which is the quickest way to check whether your platform has implemented it.

UCP is protocol-agnostic at the implementation level: it supports REST, the Model Context Protocol (MCP), Agent Payments Protocol (AP2), and the Agent2Agent (A2A) protocol. Agents built on different platforms can interact with merchants through UCP without requiring bespoke integrations. AP2 is Google’s authorisation layer for agentic payments: it lets users set spending limits and product constraints, with tamper-proof digital mandates creating a verifiable record between user, merchant, and payment processor.

In March 2026 Google added three capabilities to the protocol. Cart lets agents “save or add multiple items to a shopping cart at once from a single store”. Catalog lets agents “retrieve select real-time product details from a retailer’s catalog where necessary, like variants, inventory and pricing”. Identity Linking lets shoppers “receive the same loyalty or member benefits they would on a retailer’s site”. Google also announced simplified UCP onboarding through Merchant Center.⁴ Cart matters most of the three, because single-item checkout was the specific complaint that sank the first generation of in-chat buying.

At Google I/O 2026, Google introduced Universal Cart as the consumer-facing implementation: an intelligent shopping cart that works across merchants and runs background operations once items are added: monitoring price drops, surfacing price history, flagging product incompatibilities across multiple retailers, and surfacing merchant offers and loyalty perks via Google Wallet.⁵ Checkout completes via Google Pay or transfers to the merchant’s site, with the brand remaining the merchant of record. Launch merchants include Nike, Sephora, Target, Ulta Beauty, Walmart and Wayfair, alongside Shopify merchants such as Fenty and Steve Madden. At Google Marketing Live the following day, Google set out the same cart running across Search including AI Mode and Gemini, with UCP also wired into Direct Offers, Demand Gen campaigns, and Shopping ads on YouTube.⁶⁷ UCP is also extending to additional verticals including hotel booking and local food delivery.

Google’s help documentation now describes both as live rather than forthcoming, and it is the better place to check current scope. Universal Cart is “currently available only in the United States”, where shoppers add items from Google Search and Shopping, AI Mode and Gemini Apps; YouTube and Gmail are not yet listed.⁸ For merchants, UCP-powered checkout “applies to products with eligibility in the United States, Canada, and Australia”, so the Canada and Australia expansion announced in May has landed and the UK has not.⁹

How does Stripe support agentic commerce?

Stripe has built a payment infrastructure layer for agentic commerce through three components:

The Agentic Commerce Protocol (ACP), co-developed with OpenAI and released as an open standard in September 2025, was the earliest and most consumer-visible of these standards, and it predates UCP by three and a half months.¹⁰ It launched as the protocol behind ChatGPT’s Instant Checkout; since that feature was scaled back, OpenAI’s own developer documentation describes ACP as the layer that “enables ChatGPT to ingest structured catalog data, understand merchant inventory, and surface relevant products in context”.¹¹ The specification itself is published under the Apache 2.0 licence and is REST and MCP compatible.¹²

The Agentic Commerce Suite allows merchants to upload a product catalogue and manage agent access from the Stripe Dashboard. The suite handles discovery, checkout, and payment for agent-initiated transactions. For merchants already using Stripe for payment processing, this layers onto existing infrastructure without requiring a new payment integration.¹³

The Machine Payments Protocol (MPP), co-authored by Stripe and Tempo, allows AI agents to complete transactions programmatically, covering microtransactions and recurring payments. Stablecoins are accepted directly; fiat payments, meaning cards and buy now, pay later methods, arrive via Shared Payment Tokens. It operates at the payment execution layer, distinct from MCP (which handles agent-to-tool communication more broadly), and Stripe’s announcement states support for both MPP and the x402 payment standard.¹⁴ ACP, UCP and x402 are designed to compose rather than compete, so a merchant is not choosing between them.

How does Perplexity’s Instant Buy work?

Perplexity has run in-chat checkout with PayPal since November 2025. Its help centre describes Instant Buy as letting “U.S. users search for and buy products from a wide range of merchants directly on Perplexity, with a seamless, secure checkout flow”, where the shopper’s “order and payment are securely sent directly to the merchant for fulfillment”, so the retailer stays merchant of record. Perplexity supports Instant Buy “with merchants who are compatible with our agentic checkout experience”, and says its answer engine “is more likely to recommend merchants who provide deeper product details such as availability, reviews, pricing, and specifications”.¹⁵ For merchants on neither Shopify nor Stripe, PayPal’s store sync and agent ready tools are the low-effort route into it.

What are Shopify’s agentic channels?

Shopify’s Agentic Storefronts connect Shopify merchant catalogues into ChatGPT, Google AI Mode and Gemini, Microsoft Copilot, and Meta.¹⁶ For Shopify merchants, this is a sales channel configuration in the Shopify admin, not a custom technical integration.

The four channels are not equivalent, and the difference decides whether a purchase happens inside the conversation or on your own site. Shopify documents ChatGPT as “a discovery-focused referrer platform”: shoppers complete the purchase in the merchant’s own checkout, in a ChatGPT in-app browser or a new tab, and there is no direct-checkout setting for it in the admin at all. Google AI Mode and Gemini, Microsoft Copilot and Meta each support a Shopify-powered direct checkout that finishes in the channel. Two constraints go with that. The Google channel and its direct checkout are both still rolling out to eligible stores, and direct checkout there requires a store based in the United States selling to United States customers, and is shown only to customers in the United States. Shoppers elsewhere can still discover the products; they are redirected to the online store to buy.¹⁶

What is the difference between agentic commerce and AI shopping recommendations?

The distinction matters for implementation priority.

AI shopping recommendations (covered in AI shopping agents and ecommerce visibility) describe AI systems surfacing product suggestions within conversational interfaces. The user still navigates to the merchant’s site and completes checkout manually. Optimising for this requires catalogue quality, structured data, and Merchant Center completeness: no new infrastructure.

Agentic commerce describes AI agents completing the entire purchase: selecting, adding to cart, and paying, with the user confirming or delegating the transaction. This requires the merchant’s systems to accept programmatic purchase requests from agents, not just browsing traffic. It is a fundamentally different technical relationship.

A merchant can be well-positioned for AI product discovery without any agentic commerce infrastructure. Conflating the two leads to either under-investment (dismissing AI shopping recommendations as “too speculative”) or over-investment (building agentic checkout infrastructure before demand exists).

What should merchants implement now?

The current cost-benefit ratio favours low-effort, infrastructure-adjacent steps:

Ensure Merchant Center data is accurate and complete. Required for Google AI Mode and Shopping Graph inclusion regardless of agentic developments.

Check your Agentic Storefronts channels if you are a Shopify merchant. Agentic storefronts is active by default for eligible stores, so the step is not enrolment: confirm which channels the store is participating in under Sales channels > Agentic, and accept the Agentic Storefronts supplemental terms. Shopify’s documentation describes the Google AI Mode and Gemini channel as still rolling out to eligible stores, with its direct checkout rolling out to Google users in parallel.¹⁶

Review Stripe’s Agentic Commerce Suite if you use Stripe. Product catalogue upload is a low-effort step toward agentic discovery infrastructure. Stripe’s announcement directs interested merchants to a waitlist rather than to general availability, so check the current status before planning around it.¹³

If you are on neither Shopify nor Stripe, look at Shopify’s Agentic plan. It syndicates a product catalogue to “ChatGPT, Google AI Mode and Gemini, Copilot, Perplexity, the Shop app” with no Shopify online store required, no monthly fee, and card rates from 2% + 25p.¹⁷ It is a catalogue service rather than a commerce migration.

If you want UCP-powered checkout on Google, the step is applying, not building. Google runs it as an early-access programme: the checkout feature “is available for select merchants at this time”, and the route in is to meet the stated requirements, submit Google’s interest form, then complete the technical implementation, with onboarding handled through Merchant Center. Only listings carrying the native_commerce(checkout_eligibility) product attribute show a Buy button in AI Mode or Gemini.⁹

Monitor AI-attributed orders in GA4. The ‘AI Assistant’ channel group and custom Perplexity segments establish a measurement baseline before the channel becomes more significant.

Those steps have an order. Maintain catalogue and data quality first, which serves AI recommendations, Shopping and agentic discovery alike; then take the low-effort channel steps above; then monitor the channel as volume data emerges; and commit engineering investment only when transaction data justifies it for your specific store. Merchants who built for the first wave built against a surface that was then withdrawn; the Agentic Commerce Protocol itself is intact, and OpenAI continues to work with Stripe on it for app-based transactions.¹⁸

Can merchants block shopping agents?

The legal position shifted in August 2026. Amazon sued Perplexity in November 2025 over the shopping agent in its Comet browser, under the Computer Fraud and Abuse Act and California’s equivalent, and won a preliminary injunction from the Northern District of California on 9 March 2026. On 4 August 2026 the Ninth Circuit vacated that injunction and sent the case back for further proceedings, holding that the statutes regulate human action and that “however advanced the Assistant currently is, it is a tool, not a person”. The court’s reasoning was that “it is the user who accesses Amazon’s computers, with the help of the Assistant to carry out specific acts on Amazon.com”.¹⁹²⁰

It is the first circuit court to rule on the intersection of agentic AI and the Computer Fraud and Abuse Act, and the underlying suit continues.²¹ The ruling is confined to those statutes: they do not keep an agent out when it runs on the shopper’s own machine, which leaves a merchant’s own terms of service as the remaining route. Merchants have taken opposite positions on using it. Amazon has fought to exclude third-party agents throughout, from its November 2025 cease-and-desist onward; Walmart told WIRED in March 2026 that it had not blocked other AI agents from shopping on its website and did not plan to, on the grounds that it does not “want to block things on a speculative or hypothetical concern”.²²

What is still speculative?

Custom MCP endpoint development, bespoke agent APIs, and custom agentic checkout integrations require engineering investment that is not supported by published transaction volume data for most merchant categories.

How much agentic commerce is actually happening?

The company furthest ahead was the first to retreat. OpenAI launched Instant Checkout in September 2025, then pulled back in March 2026, rerouting purchases toward third-party apps and the merchant’s own site rather than completing them in the chat.¹⁸ The reasons are more instructive than the reversal itself.

Merchant adoption was thin, though the exact figure is contested: the number reported at the time was about a dozen Shopify merchants live with the feature, while Shopify told Forrester it was closer to 30 and climbing.²³ Against a merchant base in the millions, either figure is negligible. That thinness was not merchant reluctance, though. Shopify president Harley Finkelstein said the holdup was on the AI firms’ side.²⁴

UCP adoption is at a similar stage. On Shopify’s Q2 2026 earnings call in August, Finkelstein put it at “dozens of retailers and platforms” since the protocol launched in January.²⁵

The demand signal is more revealing. From November 2025 Walmart made around 200,000 products buyable inside ChatGPT. Daniel Danker, who oversees product and design at Walmart, told WIRED that conversion ran three times lower for that in-chat selection than for the items ChatGPT showed which required clicking out to Walmart’s site.²² Both sets were surfaced inside ChatGPT, so this measures two checkout routes against each other rather than ChatGPT against walmart.com as traffic sources. The two sets are not like for like either: Walmart deliberately withheld products where buying a single item in isolation is a poor experience, such as a television the buyer will want to bundle with cables.

Danker’s own diagnosis is narrower than a verdict on agentic checkout. The problem he names is basket fragmentation. Instant Checkout buys one item at a time, and shoppers “generally don’t want to split the checkout experience”, fearing five separate boxes when they wanted one delivery. That is a flaw in the first implementation rather than evidence that people will not buy through an assistant. The counterweight points the same way: Danker says ChatGPT brings Walmart roughly twice the rate of new customers as search engines do. Discovery through the assistant was working; the checkout inside it was not. Both figures are executive commentary rather than audited disclosure, and Danker did not present the underlying data.

That changes what the reversal means. Walmart’s replacement is not a retreat from AI shopping but a change of venue: its own chatbot, Sparky, runs inside ChatGPT and arrived in Google’s Gemini a month later, so the basket persists and checkout stays on Walmart’s rails. This is OpenAI’s pivot “to apps” in concrete form, and it is the shape the near-term opportunity takes. So the infrastructure is real, but “operational” needs qualifying: the specifications, payment rails and platform channels genuinely exist and work, while the consumer behaviour that would justify bespoke merchant investment does not yet.

Footnotes

1. Under the Hood: Universal Commerce Protocol — Google Developers Blog ↩ ↩²

2. Read Sundar Pichai’s remarks at the 2026 National Retail Federation — Google Blog ↩

3. Building the Universal Commerce Protocol — Shopify Engineering ↩

4. New Universal Commerce Protocol capabilities — Google Blog ↩

5. Google Shopping introduces Universal Cart, agentic shopping — Google Blog ↩

6. Google expands Universal Commerce Protocol — Search Engine Land ↩

7. How we’re helping retailers thrive with new Universal Commerce Protocol features and AI tools on Google — Google Blog ↩

8. Manage your universal cart — Google Wallet Help ↩

9. About the Universal Commerce Protocol (UCP) and UCP-powered checkout feature on Google — Google Merchant Center Help ↩ ↩²

10. Stripe and OpenAI launch Instant Checkout and the Agentic Commerce Protocol — Stripe ↩

11. Agentic Commerce Protocol — OpenAI Developers ↩

12. Agentic Commerce Protocol ↩

13. Introducing the Agentic Commerce Suite — Stripe ↩ ↩²

14. Introducing the Machine Payments Protocol — Stripe ↩

15. What is Instant Buy? — Perplexity Help Center ↩

16. Agentic storefronts — Shopify Help Center ↩ ↩² ↩³

17. Shopify Agentic plan — Shopify ↩

18. OpenAI’s big ChatGPT Instant Checkout plan just changed — Search Engine Land ↩ ↩²

19. Ninth Circuit: AI agent’s access to website is not a CFAA violation — Metropolitan News-Enterprise ↩

20. Perplexity has successfully overturned Amazon’s injunction on its AI shopping bot — Engadget ↩

21. Ninth Circuit Addresses CFAA and Agentic AI Tools in Groundbreaking Decision — Wilson Sonsini ↩

22. Why Walmart and OpenAI are shaking up their agentic shopping deal — WIRED ↩ ↩²

23. What it means that the leader in agentic commerce just pulled back — Forrester ↩

24. Why OpenAI’s checkout retreat spells trouble for its commerce strategy — Forbes ↩

25. Shopify (SHOP) Q2 2026 earnings call transcript — The Motley Fool ↩