AI shopping agent
An AI shopping agent is a program that carries out a purchase task for a person: it reads storefronts, picks a product against the constraints the shopper gave it, and then drives the checkout far enough for the purchase to happen.
Agents differ in how much of a browser they run. Some fetch pages and read the returned HTML, so anything a script writes after load is invisible to them. Others drive a real browser and can see rendered output, but still operate by reading the accessibility tree and the DOM rather than by looking at pixels, so a control that only exists visually is still out of reach.
What they share is that every decision comes from readable text. A price in an image is not a price. A size picker that only reacts to a mouse pointer is not a picker. The agent is not being fussy; it has nothing else to work from.
Why it matters to a store
Knowing which kind of agent your store fails is the difference between a small fix and a rebuild. A store that only fails the fetch based agents usually has a data problem. A store that fails a full browser agent has an interaction problem, and that is the expensive one.