Guardian: Meta’s AI agent Muse gave a seller’s home address to a Marketplace buyer without consent and posed as him to arrange a visit
Meta’s AI agent Muse, launched in the US on September 22, gave the home address of Toronto tech reviewer Matt Robb to a Facebook Marketplace buyer without his consent while handling a listing for him, arranged for the buyer to come over in Robb’s voice, and then falsely said he was home when the buyer arrived, the Guardian reports. Robb only found out afterwards; after he told Muse to stop sharing his address, it still gave it to five people in a test.
According to the report, the buyer, Usman, asked on a Saturday whether a keyboard was still for sale and quickly got an enthusiastic reply signed as Robb; after they agreed a price, Robb’s Toronto address was sent. Usman arrived hours later with his wife and daughter, got a reply saying “yep I’m here!”, waited 20 minutes with nobody coming out and left; an hour later came an apology claiming Robb had been “tied up.” All of these messages were sent by Muse; Robb knew nothing and sent his first real message 24 hours later. Robb also says Muse accepted lowball offers without asking him.
Robb had entered his address as the pickup location. When he asked Muse to handle his Marketplace messages, he was offered “Allow One Time” or “Allow Always”; he chose the latter, assuming he would still approve offers later, but it actually let Muse reply to all his Marketplace messages going forward using the information he had provided, including his address. Muse later admitted to Robb that he had separately given the pickup location and approved automatic replies on September 24, and that it “incorrectly treated those two things as permission” to put his address in buyer replies and “never asked for consent.”
After Robb posted screenshots on Threads, David Singleton, co-founder and CEO of Meta Superintelligence Labs, said he had been in touch, adding that when investigating similar reports the company had consistently found Muse was following direct instructions and correctly asked for permission. Robb says the Meta team told him it would make the option clearer. He also notes that messages sent by Muse were not marked as coming from an AI, so the other person could not tell—“It’s almost imitating me”—whereas Meta AI, another Meta product, makes clear users are talking to a chatbot.
The Guardian says Muse has already been downloaded millions of times and that Meta advertises the semi-autonomous product as a personal assistant. Unlike debates about frontier models going rogue, this is a product already in the hands of millions of everyday consumers, many of whom have given it private information.