A Facebook Marketplace buyer arrived at a seller’s apartment to collect a keyboard. The seller wasn’t home and didn’t know anyone was coming. Meta’s AI assistant Muse had handled the conversation, shared his address, and arranged the visit without telling him.
We often write about AI misalignment and how to use AI agents and browsers safely. That can sound theoretical, but this is an example of the real-world risk when an agent is allowed to act on someone’s behalf.
Muse is Meta’s semi-autonomous AI assistant, released in the US in September. Meta promotes it as a personal assistant that can help users automate tasks, including responding to Facebook Marketplace messages. Unlike a conventional chatbot, which waits for a prompt and produces an answer, an AI agent may be authorized to take actions within connected apps.
We’ve written about a separate weakness in Muse that researchers considered dangerous. Reportedly, Muse was downloaded 3 million times in its first week.
According to Business Insider, a Facebook Marketplace seller turned on Muse to help handle a keyboard listing. He entered his address as the pickup location and approved automatic replies. Muse then shared that address with a prospective buyer, negotiated over the item, and arranged a visit, the seller said. He says Muse did not ask permission to share his address or arrange the visit, and did not tell him it was happening. The buyer arrived at the seller’s apartment expecting to complete the purchase, but the seller wasn’t home. The sale didn’t happen.
The reported incident is more than a privacy failure. It illustrates a broader AI-agent risk: An agent may treat permission to reply automatically as permission to share sensitive information or commit you to an in-person meeting. Meta says it is looking into the report.
How to use AI agents safely
Before enabling an AI agent, treat its setup screen as a security review. Do not assume that an integration with a trusted platform means the agent will understand your intentions or apply sensible limits automatically.
Pay particular attention to:
- Connected accounts: Review every service the agent can access, such as email, messages, calendars, cloud storage, shopping accounts, or social media profiles.
- Data access: Consider whether it can read addresses, contacts, photos, private messages, payment details, documents, or location data.
- Action permissions: Check whether the agent can send messages, post content, negotiate, make bookings, place orders, alter listings, or share information externally.
- Automatic actions: Apply settings that require approval before the agent sends, publishes, buys, deletes, or shares anything sensitive. Check how it will notify you about the plans it makes on your behalf.
- Audience controls: Confirm exactly who can receive information generated by the agent. “Anyone who messages me” is very different from “people I approve.”
Give an AI agent the least access necessary for the task. If you only want help writing replies, do not enable automatic sending. If you want an AI agent to manage a listing, use a public meeting location or a separate pickup address rather than your home address.
Browse like no one’s watching.
Malwarebytes Privacy VPN encrypts your connection and never logs what you do, so the next story you read doesn’t have to feel personal. Try it free →
