You don't have to use Meta's Muse for it to read your messages

Meta's AI assistant Muse has surpassed 10 million users, roughly a quarter of whom use it every day, according to figures the company gave on its third-quarter earnings call. Alongside that scale, Meta has begun explaining a more uncomfortable question: what happens to the data of people who do not use Muse at all, when their friends connect email, calendars and messaging apps to it.

ZDNET's reporting puts the conclusion bluntly. Not using Muse does not mean your information stays out of it. Meta's help-center guidance says Muse can gather information about non-users when a user connects apps and services that contain that data, and when a user submits text, images, videos or uploaded documents that mention other people.

Meta's own example is mundane. If a Muse user connects a calendar app and asks what meetings are scheduled for the week, the names of attendees and event details can be included in the request and the response. A conversation about travel plans, a medical problem, a job change or a financial worry can therefore be processed by an assistant you never agreed to use, simply because you talked to someone who did.

Connectors are the machinery behind this, the API bridge between a Muse virtual machine and third-party services. At launch, Meta chief AI officer Alexandr Wang listed Gmail, Google Calendar, Outlook, Plaid, OpenTable, Google Docs, Spotify, Function Health, Withings, Tailscale and Peloton among them, and Facebook, Instagram and Threads connect automatically when the Muse account shares credentials with the Meta Account Center. If a connector does not exist, users can ask Muse to make an API call to another service on their behalf.

The permission surface is broad. Launched on September 8 as an assistant that "gets it done," Muse asks for access to contacts, calendars, email and even offers to store logins and passwords. Its Android data-safety listing covers photos and videos, financial information, files and documents, contacts, web browsing, health and fitness, messages, audio and location, and training on interactions is on by default unless a user opts out.

Meta's answer on protection is "reasonable identification" rather than anonymity. The company says that if non-user data is viewed or ingested by Muse, it will not be linked to a Meta account and will not be stored in a way that lets Meta reasonably identify whose information it is. Calli Schroeder of the privacy group Epic.org argued that without better protections, Muse becomes "a nightmare for people even when they actively choose not to engage with it."

Non-users have few levers. Muse users can turn off AI training and adjust permissions, though reporting has questioned whether those permission settings are respected. Non-users can mainly object under local data-protection law, and even that may not cover Muse conversations.

Meta says a confidential virtual machine, which would keep people's information private even from Meta, is planned but not yet available. Until then, the boundary around Muse depends on user settings and Meta's own restraint, which is why an assistant that has only just passed 10 million users has become a fresh focal point in the AI privacy debate.