Meta’s Muse AI agent has been blocked from shopping Amazon on behalf of its users, GeekWire reports. A popup message started appearing on Sunday for Muse users saying that “continued access by an unauthorized AI agent violates Amazon’s Conditions of Use, to which our customers have agreed.”

According to GeekWire, Meta didn’t notify Amazon that Muse would access its store. Amazon also expressed privacy and security concerns over Muse failing to identify itself when it browses, and seemingly capturing customer credentials.

“We think it’s fairly straightforward that third-party applications that offer to make purchases on behalf of customers from other businesses should operate openly and respect service provider decisions about whether or not to participate,” an unnamed Amazon spokesperson said in a statement to GeekWire. We have reached out to Meta for comment.

This marks Amazon’s latest effort to fend off competition from rival agentic AI services and keep its customers shopping with the retailer directly. It sued Perplexity in November last year in a similar attempt to keep the Amazon platform out of the AI search provider’s Comet shopping experience, with a judge siding with Perplexity on the case in August. Confirmation emails from Amazon have also started looking notably sparse since July, with specific item names and product images being omitted to limit that information from being mined by external AI services.