The RealReal, a secondhand luxury fashion consignment retailer, said it’s updating its bot defense system, effectively making it harder for AI agents to shop on its site.

The change comes days after The Vergereported that an AI agent could be used to take advantage of The RealReal’s item reserve system. On the retailer’s website, an item goes “on hold” and is unavailable for other customers to buy for 20 minutes once it’s placed in a user’s shopping cart. Using Meta’s Muse, The Verge was able to instruct the AI agent to continuously re-add The RealReal listings in a shopping cart as soon as the 20-minute hold had expired, effectively blocking other shoppers from purchasing products for hours or longer.

After publication, chief technology officer Luke Friang said in an email that the company had addressed the Muse use case flagged by The Verge’s story. The RealReal’s bot defense configuration now makes it much more difficult for all agents to log in, add items to cart, and check out, Friang said. Agents will still be able to surface listings from The RealReal and direct Muse users to product pages, Friang said, adding that the company will continue to strengthen protections as AI-powered online shopping evolves.

Meta didn’t immediately respond to a request for comment.

Technology companies are selling agents as personalized assistants for billions of people — always-on, compliant entities that will schedule meetings, throw parties, and purchase things for human users. So far, agents and shopping seem to go hand in hand; Meta said in its Q3 earnings call this month that it was the most common use case for Muse so far, and that purchases were over $200 on average. Muse has been a hit for Meta and could signal a turning point for AI agents: The company said 10 million people in the US had downloaded the app in 40 days.

But robots shopping for things instead of humans has the potential to upend the balance of the web as we know it. For one, if humans stop visiting websites directly and instead access the web through chatbots, businesses become one step removed from their customers. Retailers — most notably Amazon — have recognized that reality could disrupt their bottom line, especially advertising revenue, and have blocked agents from shopping on their sites.

An influx of AI agents accessing consumer platforms could also break or complicate even the most unexpected things shoppers take for granted, like the reserve system of a used clothing website. There is, of course, a realistic limit to how long a person is willing to spend adding and re-adding designer clothing to their shopping cart if they’re indecisive. An agent in contrast does not care. It is perhaps precisely the type of busywork a fashion-forward person might pay an actual personal assistant to do on their behalf. Now, a capability like this is at the fingertips of millions of consumers, and they are just beginning to learn how to take advantage of it. Retailers, too, are playing catch-up.