Agentic Commerce: What Is Live, the Protocols Behind It, and What It Means for Advertisers

Agentic commerce is shopping in which an AI agent finds, compares and buys on a person's behalf. McKinsey defines it as "a model in which artificial intelligence (AI) agents shop, negotiate and transact on behalf of humans". In October 2026 most of it is narrower than that definition: an assistant recommends a product inside a conversation, and the person confirms a checkout without leaving the chat. Fully autonomous buying exists in a few places. This guide covers what is live, the protocols behind it, the forecasts, and what changes for brands that advertise.

What is agentic commerce?

The definitions agree on the agent and differ on how far it goes. Stripe calls it shopping in which "AI agents finding, comparing, and potentially making purchases for customers"; Shopify calls it the stage "where AI agents help consumers browse and shop". The useful distinction is between three levels of delegation:

Most of the volume and almost all of the forecasts are about the first two levels. Delegated purchase is real but bounded: Amazon's auto-buy, for example, notifies the customer with "free 24-hour cancellation".

Where can people buy through an AI agent today?

• Google began agentic checkout in Search and AI Mode in November 2025 and says its protocol now "enables direct checkout for hundreds of thousands of brands and retailers." Universal Cart, live in the US since October 15, 2026, carries one cart across Search and the Gemini app, with the merchant remaining "the seller of record." See our Gemini ads guide.
• Microsoft launched Copilot Checkout on January 8, 2026 with PayPal, Shopify and Stripe; "you stay the merchant of record." See our Copilot ads guide.
• Amazon merged Rufus and Alexa+ into Alexa for Shopping, and says customers who use it "spend an average of over 40% more per order".
• Perplexity added in-chat checkout with PayPal for all US users in November 2025, with retailers as merchant of record.
• ChatGPT launched Instant Checkout with Etsy in September 2025 and Walmart signed on in October. In March 2026 OpenAI said Instant Checkout "is moving to Apps" and that it was "prioritizing making ChatGPT search and product discovery great." Shopify reports merchants are reached in ChatGPT with the purchase completing on their own store.

Two patterns run through every row. The merchant stays the seller of record, and the assistant owns the moment of choice. Availability is overwhelmingly US-only; Shopify notes that purchasing "across all channels is currently available to US buyers only".

The protocols behind it

Agents need a standard way to read a catalog, pass a payment credential and prove they act for a real person. Five efforts matter:

The Agentic Commerce Protocol launched with Instant Checkout in September 2025; Stripe's documentation now lists it as "an open standard created by Stripe, OpenAI, and Meta". Google's Universal Commerce Protocol was "co-developed with industry leaders including Shopify, Etsy, Wayfair, Target and Walmart," and its Agent Payments Protocol covers how agents "securely initiate and transact agent-led payments across platforms." On the card side, Visa's Trusted Agent Protocol lets agents and merchants verify each other, and Visa said in December 2025 that "hundreds of secure, agent-initiated transactions" had been completed. Mastercard promised Agent Pay to all US cardholders for the 2025 holidays.

How big is agentic commerce?

Forecasts are large and far apart, which tells you how early this is:

McKinsey adds $3 trillion to $5 trillion globally and measures "orchestrated" revenue, which includes purchases an agent influenced; Morgan Stanley counts sales by agentic shoppers and puts them at 10 to 20 percent of US ecommerce. Salesforce attributes sales to AI and agents across its commerce platforms; Adobe measures traffic, not purchases. None of these is the number of autonomous agent transactions, which no one publishes.

Consumers are ahead of autonomy but behind discovery. Accenture's 2026 survey of 25,590 people found "one in three (32%) are ready to hand over purchase decisions" and "9% are open to fully autonomous shopping." Morgan Stanley found nearly 23 percent of Americans made an AI-assisted purchase in the past month.

What agentic commerce means for advertising

If an agent shortlists products, the ad that matters is the one present when the shortlist forms. Every large platform is building for that moment, and each has kept the ad labeled and separate from the agent's own judgment:

• OpenAI is testing Sponsored Agents: after clicking an ad, a person can "start a clearly labeled conversation with a business-sponsored agent," kept "separate from the original conversation in ChatGPT and from ChatGPT's independent answers."
• Google offers a Business Agent, "like a virtual sales associate that can answer product questions in a brand's voice," and Direct Offers, which retailers configure and Google's AI shows in AI Mode when relevant.
• Microsoft sells Brand Agents, "AI-powered shopping assistants that speak in your brand's voice," alongside Copilot Checkout.
• Amazon made existing sponsored ads campaigns automatically eligible in Alexa for Shopping and launched Alexa+ Agentic Ads, which take a customer "from seeing an ad to completing a purchase entirely within the conversation."

Three practical consequences for brands:

• Product data becomes media. Agents read feeds, not banners. Complete, accurate catalog data in Merchant Center, Shopify and your commerce platform is the price of being considered.
• The placement moves earlier. Paid presence works when it appears in the conversation where the need is stated, before the agent narrows the field. After the cart is built, it is too late.
• The agent will not be bought. Every seller says its assistant's recommendations are independent. What advertisers buy is a labeled placement next to the conversation, or a sponsored agent the person chooses to talk to.

That is the layer Thrad works in. Thrad places sponsored, labeled messages inside AI conversations across independent AI apps, matched to the need the person has just stated. Microsoft featured our chief commercial officer on agentic commerce. Thrad lets you run one budget across the AI apps your customers already use. Launch a campaign from self-serve.

Risks and open questions

• Liability is unsettled. Worldpay notes that "liability allocation between merchant, issuer and agent platform remains largely unresolved", though transactions authenticated through Visa or Mastercard agent programs generally follow existing tokenized-transaction rules.
• You answer for your agent. The UK Competition and Markets Authority told businesses in March 2026 that "you are responsible for what an AI agent does in the same way you are responsible for what an employee does".
• Merchants and agents disagree about access. In August 2026 the Ninth Circuit vacated Amazon's injunction against Perplexity's Comet shopping agent, finding that Perplexity's users, not Perplexity, accessed Amazon. Expect more of these disputes.
• Checkout may not stay with the assistant. OpenAI's move from Instant Checkout to merchant apps shows the platforms are still deciding where the transaction belongs.

An agentic commerce checklist for brands

1. Make your catalog agent-readable: complete feeds, structured attributes, live inventory and prices.
2. Enable checkout where your customers already ask: Google UCP through Merchant Center, Copilot Checkout through PayPal, Shopify or Stripe, and ChatGPT through Shopify.
3. Decide on brand agents deliberately; Google, Microsoft and OpenAI each now offer one.
4. Budget for labeled placements inside AI conversations, where the need is stated, not only for search and retail media.
5. Track AI-referred traffic and orders separately, since the platforms rarely report them for you.