What Is Muse? Meta's Personal Agent, Spark, Glimmer and Connectors Explained

Muse is Meta's personal AI agent: it runs errands, manages schedules, fills forms, books travel, browses and makes purchases, and keeps working in the background after you close the app. The name also covers the models and tools around it: Muse Spark, a closed reasoning model that powers the agent and is sold to developers; Muse Glimmer, an open-weights model you run yourself; Muse Code, a terminal coding agent; and connectors, which let the agent act inside services like Gmail, Plaid or Ticketmaster.

How it works, in one mental model

Think of Muse as a worker with a brain, a private computer, a set of keys, and a supervisor who holds the keys.

The brain is Muse Spark. The personal agent is powered by Muse Spark 1.3, Meta's closed-weights model tuned for long-horizon coding and agentic work. It has a context window of 1,048,576 tokens and takes text, image, video and document input (Meta's docs). Developers can call the same model through the Meta Model API at https://api.meta.ai/v1, which Meta describes as drop-in compatible with the OpenAI and Anthropic SDKs.

The computer is a dedicated VM. Each user gets their own Muse Secure VM, and the agent does its work there (Meta's security write-up). Users have poked at it directly. Greg Ceccarelli got Claude Code running inside his Muse agent's VM and reports 2 vCPUs, about 8GB of RAM and 100GB of disk, with no inbound ports. Peter James had the iOS app zip the agent's filesystem and found a home directory with soul, identity and memory files. Those are the authors' observations, not Meta specs.

The keys are connectors. A connector gives the agent structured access to a service. Meta describes three kinds (help page):

• Directory connectors, reviewed by Meta. At launch these included Gmail, Google Calendar, Google Docs, Outlook, Plaid, Stripe Link, Shopify Catalog, OpenTable, Ticketmaster, Function Health, HealthEx, Withings, Peloton, Duffel and Tailscale (sourced list).
• Custom connectors, which Muse builds itself from any API. Credentials sit in a secure store, and Meta does not review them. One user had Muse build a Linear connector in under a minute.
• Meta's own apps. Facebook, Instagram and Threads connect automatically through Accounts Center.

Any connector can be set to read-only. When there is no connector, the agent falls back to its browser, which is how it claimed flight delay compensation from Delta and paid a Verizon bill with a gift card.

The supervisor is Sentinel. A separate authority called Sentinel gates connector actions and network egress. Credential surrogation keeps secrets away from the model itself. Prompt injection is handled in layers: model training, labeling of untrusted input in the harness, classifiers, and human approval. Meta runs a bug bounty of up to $300,000 (source).

The surfaces. You talk to the agent on iOS, Android, the web at muse.ai and WhatsApp. Muse for Mac arrived on September 17–18 and lets the agent work with local files, Messages, Notes, Reminders, Mail and Calendar. Each app can be set to Off, Read only, or Read and interact (help page). At Meta Connect 2026, Meta announced voice mode, a Realtime Avatar, an email address for the agent, broader Mac computer use, glasses integration, and a pocket device called Muse Charm.

The developer side. Two more pieces sit next to the agent:

• Muse Code is a terminal coding agent co-trained with Spark. It supports subagents in isolated git worktrees, replayable event logs and skills like /plan. Plans start at $5 a month (product page).
• Muse Glimmer is a ~29.6B dense model released on August 10 under Apache 2.0 and distilled from Spark. It has a 131,072-token context and takes text and image input. Meta says it fits in under 20GB at 4-bit and targets 24–32GB devices (model card).

What it costs. For the agent, Meta's help page lists a usage-limited Free tier, Power at $20 a month for 500M Muse tokens a week, and Max at $100 a month for 3B tokens a week (source). There is no published conversion from tokens to tasks. On the API, standard Spark pricing is $1.25 per million input tokens and $4.25 per million output. A cheaper Contributor tier costs $0.10 and $0.20, and Meta may train on that data (pricing).

What Muse is being used for

This catalog holds a little over 220 filed entries, and they cluster in a few clear places.

Errands that pay for themselves. The most-shared stories are about money recovered. Chandra Bhavanasi reports Muse cut an AT&T fiber bill from $80 to $40. Idobn's receipt audit found a forgotten $100 a month subscription. Another user had it search every state's unclaimed property database and turn up $88.92. The failures are instructive too. When raunaq's Muse called Xfinity, it reached a human but couldn't read a verification text, so it patched him into the call.

Connectors, lots of them. Tools & apps is the largest shelf, and much of it is connector work: a Cloudflare Workers starter, a CalDAV proxy for self-hosted calendars, a connector for HVAC and plumbing shops, and a pack of 150 one-paste connector skills. Meta told TechCrunch it received more than 1,500 platform applications in under a week.

Running Glimmer locally. A large share of research & data is people fitting Glimmer on hardware. One runs it in 12GB of VRAM at 100K context. Another put it on a Qualcomm Dragonwing board for PCB inspection. A third reports a negative result on a Dell GB10.

Games and one-shot demos. Spark 1.3 gets asked to build games constantly, from a pirate platformer to a Minecraft-style world the author says cost 10 cents. Dilmer Valecillos converted a minigolf prototype to Quest 3 VR with Muse Code and published the prompts.

Wrapping Muse Code. Developers keep putting Muse Code inside other tools: a desktop app, JetBrains and Zed support, a remote web terminal, and Claude Code plugins that delegate to it.

What Muse is not

It is not available everywhere. At launch the agent is US-only and 18+, and Meta describes the agent and its subscriptions as being in "limited testing".

It is not welcome on every site. Amazon blocked Muse from purchasing as of September 20. One user responded by building a small cart API Muse reaches over SSH.

It is not infallible or fully private. Meta's own Mac help page warns: "Your agent may be inaccurate or take unexpected actions." Malwarebytes reported Patrick Wardle's Mac zero-day, in which a local app redirects dictation traffic and exposes auth tokens. Taylor Arndt found real VoiceOver gaps. Meta says Muse data is excluded from its ad systems and that users can opt out of training.

It is not proven by its benchmarks. Meta reports Spark 1.3 at 75.4 on DeepSWE v1.1. Independent tests are mixed. DataCamp measured a net 12% cost increase on three tasks where Meta claimed about 25% fewer tokens. MindStudio got a cube shooting at other cubes from a game prompt.

It is not one product. "Muse" on a headline could mean the consumer agent, the API model, the open weights or the coding CLI. Check which one before you compare numbers.

Where to go next

• New here: Start Here has reading paths by role.
• Designing tasks or connectors: What Is Muse Engineering?.
• Browse by use: Agents & browsers, Triage & routing, Games & real time.
• Official sources: the Muse developer platform and Meta's model docs.
• Built something? Submit it.

Frequently asked questions

Is Muse free?

There is a usage-limited Free tier. The Batch reports it at up to 100M tokens a week. Paid plans are Power at $20 a month and Max at $100 a month, and both raise the weekly token allowance.

What model powers Muse?

The personal agent runs on Muse Spark 1.3, according to Meta's launch post. Developers can use Spark 1.3 directly through the Meta Model API, Muse Code, and gateways such as Vercel AI Gateway and OpenRouter.

Can I run Muse locally?

You can run Muse Glimmer locally, since it is open weights under Apache 2.0 and is available through Ollama, LM Studio, llama.cpp, MLX and vLLM. The personal agent and Muse Spark are hosted by Meta and cannot be self-hosted. Meta has said a Spark open-weights release is coming.

How do I build a Muse connector?

You can ask Muse to build a custom connector for you from an API and key, and it stays private to your account. To get listed in the directory, apply at muse.ai/platform. Meta reviews listed connectors for functional, security and legal issues and tests them end to end.

Can Muse buy things on Amazon?

No. Amazon blocked Muse purchases effective September 20, 2026. Muse can still check out at the 1M+ businesses that accept Stripe Link, and Meta has announced further checkout partners such as Shop Pay and PayPal.