GuidesAugust 18, 202611 min read

Agentic buying: what changes for Portuguese shops when the AI buys on its own

In the US, AI assistants already complete purchases inside the conversation. In Europe the shop window arrived, not the checkout. What already works in Portugal, where the price, stock and delivery data come from, and what to prepare now.

First, the term: agentic buying is a purchase started or completed by an AI assistant on behalf of whoever asks. The user says "I want an upright vacuum for under 200 euros delivered tomorrow" and the agent compares, chooses and, in the markets where that is already possible, completes the order inside the conversation. This article says what already works and where, where the data the agent reads comes from, and what a Portuguese shop should prepare now, with sources and dates throughout.

What already exists, and where (August 2026)

The transaction inside the chat is real, but geographically confined. The state of play, market by market:

Google: agentic checkout in AI Mode launched in November 2025, United States only, with Wayfair, Chewy and Shopify shops. AI Mode itself has been live in Portugal in Portuguese since October 2025, with product panels, prices and buttons: the shop window arrived, the counter has not.
OpenAI: ChatGPT's Instant Checkout launched in September 2025 (US, Etsy and Shopify), was extended in February 2026 and pulled back in March 2026, after conversion inside the chat fell short of buying on the merchant's site. ChatGPT keeps the product carousels as a discovery layer, visible in Europe too.
Microsoft: Copilot Checkout since January 2026, US only, with half a million merchants by April.
Perplexity: buying inside the chat through PayPal since November 2025, US only.

The honest reading for Portugal: the shop window arrived, the checkout did not. And that is exactly why the moment is good: the race for presence in the window is open and almost nobody here is running it.

Where the price, the stock and the delivery come from

The agent does not read your site like a human: it reads structured data. Three layers, in order of importance today:

The Google Merchant Center feed. It feeds the Shopping Graph (more than 50 billion listings, with 2 billion updated per hour) and it is the door to AI Mode. Free listings are eligible: you do not need to buy advertising to appear. The minimum: GTIN, brand, category in the Google taxonomy, availability and shipping, with price and stock matching the page, otherwise the listing is disapproved. In May 2026 the Merchant Center gained six conversational attributes designed for AI Mode; almost no Portuguese shop fills them in yet.
The schema on the product pages. Product and Offer with OfferShippingDetails and a returns policy: it is what validates the feed and what the engines without a feed can read.
The assistants' own feeds. OpenAI published a product feed specification (registration at chatgpt.com/merchants) that accepts refreshes as often as every 15 minutes, with inventory and delivery estimate fields. Ingestion is US-first with an international waiting list. While it does not open, the most useful figure in this market applies: a March 2026 study of 43 thousand products showed that around 83% of the products in ChatGPT's carousels come from Google Shopping's organic top 40 (Search Engine Land). Translated: optimising the Google feed is optimising ChatGPT, today, from Portugal too.

And the advertising in the middle of this

The same shop window has paid space. In Google, the ads enter AI Overviews and AI Mode automatically from the Search, Shopping and Performance Max campaigns that already exist, with no separate campaign. In ChatGPT, advertising arrived in the United Kingdom in June 2026 and OpenAI announced to European users, on 15 August, that it arrives in the EEA that same month, non-personalised, on the free plans only. In the other direction, Claude and Perplexity have stated they will not have advertising. The practical consequence: an AI answer now has two columns, the earned one and the bought one, and measuring one without telling it from the other is fooling yourself.

What to prepare now, in order

1. A complete, fresh Merchant Center feed. It is the lever that moves Google and ChatGPT at the same time, and it is free.
2. Serious product schema. Product, Offer, shipping and returns on every product page, consistent with the feed.
3. The six conversational attributes. New in May 2026, practically unused in Portugal.
4. Registration in the assistants' feeds as they open to Europe, so you can transact on day one.
5. Measurement. Knowing in which buying questions your products appear, in what position, with what price shown, and who appears in your place. With no baseline, you will never know whether steps 1 to 4 paid off.

To close

Agentic buying is not a forecast: it is working, with millions of transactions, on the other side of the Atlantic. In Europe the shop window arrived first, and shop windows are won with data: price, stock and delivery legible to machines, measured week by week. It is work a Portuguese shop can start this week, and it is what we do.

Frequently asked questions

Can you already buy inside ChatGPT or Google in Portugal?

No. All checkout inside the chat is limited to the United States as of August 2026: Google's agentic checkout (Nov 2025), Microsoft's Copilot Checkout (Jan 2026) and Perplexity's Instant Buy are US-only, and OpenAI's checkout was pulled back in March 2026. What already works in Portugal is the discovery layer: product panels with prices in Google AI Mode (in Portuguese since October 2025) and shopping carousels in ChatGPT.

Where does the AI get the price, the stock and the delivery time?

From structured feeds, not from the site's text. Google feeds the Shopping Graph with the Merchant Center feed (availability, price, shipping) and with the Product and Offer schema on the pages; OpenAI has a public product feed specification with refreshes as often as every 15 minutes and fields for inventory and delivery estimates. A March 2026 study showed that around 83% of the products in ChatGPT's carousels come from Google Shopping's organic top 40: the Google feed is today the lever that moves both surfaces.

What should a Portuguese shop prepare right away?

Four things, in order: a complete, up-to-date Google Merchant Center feed (GTIN, brand, category, availability, shipping), because free listings are eligible for AI Mode without buying advertising; Product and Offer schema with shipping and returns on the product pages; the new conversational attributes in Merchant Center (May 2026); and registration in the assistants' feeds as the international waiting list opens. The checkout comes later; whoever has the data ready appears in discovery today and transacts on the day it opens.

Main sources: blog.google (agentic checkout, Nov 2025; AI Mode in Portugal, Oct 2025), openai.com and developers.openai.com (Instant Checkout and the feed spec), Search Engine Land (the carousel study, Mar 2026; the checkout pullback, Mar 2026), Microsoft Advertising (Copilot Checkout, Jan 2026), PayPal (Perplexity Instant Buy, Nov 2025). Dates cited in the body of the text.