A cookie-stuffing investigation into the AI shopping tool exposes how little visibility consumers have into what these tools do on their behalf, and how much that gap now costs brands in trust
An investigation by Bloomberg, Capital One Shopping, and independent researcher Ben Edelman found that the AI shopping browser extension Phia, co-founded by Phoebe Gates and Sophia Kianni, opened a background tab during checkout to load its own affiliate link, overwriting legitimate referral codes from other publishers before the tab closed within seconds. The behavior was observed across more than 50 retailers and occurred whether a shopper arrived at a site directly or through another publisher’s affiliate link, a process invisible to the shopper on whose behalf it was acting. Phia has described the practice as a bug introduced in a December code release and says it has since been fixed, though the findings were serious enough for the company to be suspended from Impact.com, a major affiliate platform.
A technical breakdown from a former recruit who reviewed the underlying research complicates that explanation. The auto-loading feature was controlled by a flag left active for mobile users while switched off for desktop users, where an opening tab is visible at the top of the screen. That distinction, deliberately built and deployed rather than left to chance, is difficult to reconcile with an accidental defect. It also arrives against a broader backdrop: in November 2025, the same extension was found harvesting sensitive user browsing data well beyond what its shopping function required.
Most shoppers have no way of seeing what a browsing agent does in the moments between a click and a purchase, which is precisely what makes the category valuable—and what makes behavior like this so difficult to detect until outside researchers investigate. Industry data suggests adoption of these tools is expected to grow substantially in the years ahead, even as consumer trust remains limited. That gap puts brands relying on AI intermediaries for discovery and conversion in an increasingly uncomfortable position. A consumer who assumes an agent is acting neutrally on their behalf, only to learn it was quietly routing affiliate credit to itself while logging more data than it disclosed, does not just lose faith in one startup. They inherit a broader skepticism toward the entire category of tools now sitting between shoppers and the brands they buy from.