Definition
What is Muse Code?
Muse Code is Meta's AI coding agent. You use it through the muse command line tool, which runs on macOS, Linux and Windows, and it works inside a project directory: reading files, editing them, running commands and asking for approval. Other applications can drive it over the Muse Code Session Protocol.
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What it does
- Works inside a working directory, with the files actually on disk.
- Reads, edits and creates files, and runs shell commands.
- Asks for approval before acting, according to the mode you set.
- Keeps a session per working directory, with a turn by turn history.
- Can fan work out to parallel subagents and run multi step workflows.
How you pay for it
Muse Code is used through a subscription rather than per request API keys for most people. That is why a client that routes your work through its own API metering is a common complaint: the plan you already bought stops being the thing that pays.
How other apps use it
Meta ships an MIT licensed SDK for the Muse Code Session Protocol, so a client can start muse serve and drive a session properly instead of scraping terminal output. Helicon is one such client. VS Code extensions and Agent Client Protocol bridges are others.
Frequently asked questions
Is Muse Code free?
It is used through a Meta subscription. Helicon, a client for it, is free and MIT licensed and adds no billing of its own.
Does Muse Code run on Windows?
Yes, natively, and it also runs inside WSL2.
Is Muse Code the same as the Muse assistant app?
No. Muse Code is the coding agent used through the muse CLI. The Muse assistant app for Mac is a different product.
Keep reading
- the muse CLIThe muse command line tool is how you run Muse Code. What it installs, what muse login does, and why a GUI still needs it present.
- the Muse Code Session ProtocolMSP is the JSON-RPC protocol that applications use to drive a Muse Code session over stdio, instead of parsing terminal output. What it carries and why it matters.
- Muse Code GUIYes, Muse Code has graphical interfaces. A standalone desktop and web app, VS Code extensions, ACP editor bridges and other open-source wrappers, compared honestly.
Same Muse Code. Same subscription. Better interface.
Free and MIT licensed. Signed Windows installer, universal macOS DMG, and a web build against a daemon you run.