UPDATE 9/29: After troubleshooting with Meta, Matt Robb today chalked up the Marketplace error to confusion about app permissions.
"The first thing that popped up from Muse when asking it to handle my Facebook marketplace was an option with ‘Allow One Time’ or ‘Allow Always’. I clicked the latter thinking it would still send approvals for confirmation later to accept an offer later down the line (it didn’t so be careful)," he tweeted. "By doing that it granted Muse permission to send messages on my behalf going forwards using a template it put together using information it asked from me. Which also included the pickup address that I did give to Muse (again I didn’t think it would send it out to everyone that gave me an offer so it’s worth checking)."
Muse also approved an offer that was $100 less than Robb's advertised price. "The Meta team informed me this was an error on their end," Robb says.
Robb said Meta pledged to make it more clear what permissions had been granted to Muse. He also suggested that agent-written messages include a “Sent By Muse” badge, but it's unclear if Meta plans to do that.
Robb also "made up" with the buyer. "He even came by tonight to buy something else," Robb tweeted, though he encouraged people to "double-check what permissions AI has in your life."
Original Story 9/28:
Meta’s Muse agentic assistant is one of the most talked-about AI tools, but you may not want to let it control your Facebook Marketplace negotiations. One user reported that the AI assistant shared their home address without asking for the user's permission.
Tech YouTuber Matt Robb shared their experience on Threads after a buyer showed up at their property, with the seller unaware that a deal had been made. “So, Muse handled my Facebook marketplace today. Just found out it told people my address and agreed a lowball price and then they showed up without [Muse] even telling me until late tonight that it messed up," Robb wrote.
A screenshot of the conversation shows Muse messaging late in the evening to say it was "bad news" on the item's pickup. Muse outlined how it had invited the buyer over, noting that the person messaged “a bunch of times” while waiting at the property. It apologized for not telling Robb someone was waiting.
View on Threads
Muse apologized to the buyer, noting, “I’ve sent him an apology from your account, owning it and offering to try again another day.” It also told Robb, “I should probably stop the auto-replies from claiming you’re home when I can’t verify that. Want me to change the pickup replies so they don’t promise you’re there?”
As Robb notes, “AI agents are impressive right up until they're confidently handing strangers your address.” He didn’t realize the tool would pull his address and present it to a stranger, and it's unclear where Muse obtained that information.
Meta was embroiled in a privacy scandal last week after an Inc writer found that Muse was reading their personal messages without permission. The tool told the writer it didn’t have access to full messages, despite evidence to the contrary.
At launch, Meta said Muse is built "from the ground up to be a safe, secure, private, and widely available personal AI agent." Meta did not immediately respond to a request for comment.