Muse's post on X, curated on eChai

Curated from X →

Meta launched Muse on 8 September: a standalone agent app that keeps working after you close it and comes back when it needs an approval. Meta's own examples of what it does are sending an email, booking travel, opening a browser and filling out forms, negotiating on someone's behalf, selling a car for more, lowering a bill, adjusting a training plan as the rest of someone's life shifts, and turning a recipe reel saved on Instagram into a grocery list. An agent that browses the open web can be instructed by the page it is reading, which is what has kept agents away from cards and passwords. Meta's answer is to give each person's agent its own dedicated machine in the cloud, contained so no one else's agent can reach it, and to put a second agent called Sentinel on that same machine. Meta's security write-up calls Sentinel "the sole permission authority" both for actions on connected services and for all outbound traffic: Muse holds surrogate tokens that Sentinel swaps for the real credential at the network boundary, so the agent "never sees real tokens", and an approval is put to the person in the app itself rather than inside the conversation, so nothing Muse is reading can ask on its own behalf. That write-up is also where Meta says what the launch post does not: "Muse isn't immune to attack. Prompt injection remains an open problem in the industry", and Muse will sometimes get things wrong. It runs on Muse Spark 1.3, which Meta calls its most capable model to date. It has a file system and a terminal of its own, so it can write code and build the tools a task needs, and a full browser to search, fill out forms and complete transactions. Every account gets an audit trail of what the agent has done and what it plans to do next. It pays through Link built by Stripe, and Meta says it is the first AI agent covered by Link's purchase protections; Shop Pay is coming, along with 1Password support so it can use logins a person already has. Free to start, with paid plans at $20 and $100 a month, and it is the United States only for now, on iOS, Android, the web and inside WhatsApp.

Muse 9 Sep 2026