For developers

Muse Code: Meta’s terminal coding agent, explained

Muse Code is Meta’s coding agent for the terminal and CI, built on the Muse Spark models. It’s a different product from the Muse app. Here’s how to get it running, what it costs, and how its safety controls work, from Meta’s own developer docs.

By Published Updated Facts checked 2026-10-13

Quick answer

Muse Code is Meta’s coding agent for the terminal and CI. Meta’s docs describe it as an agent that “plans, edits, and runs commands to do a task, with approvals and an OS sandbox.” It launched in beta on August 5, 2026, runs on macOS, Linux and Windows, and uses Meta’s Muse Spark models. You pay through the Meta Model API (per token), with a much cheaper Contributor tier if you let Meta train on your prompts. It’s not part of the Muse app or its plans.

About this page

Not testedThis page is based on Meta’s developer documentation and research posts, checked October 2, 2026. We haven’t installed or run Muse Code ourselves. See how we label evidence.

What Muse Code is

  • Per MetaA terminal agent. It takes on software tasks across a repository: planning changes, writing code and validating results. It works in an interactive terminal UI or headless (muse exec) for scripts and CI.12
  • Per MetaPersistent subagents. Meta says it runs a main agent plus background agents that stay active through a session, rather than being created for each task.2
  • Per MetaBuilt-in skills. /plan turns a task into an approval-gated plan, /grill stress-tests that plan, and /goal works toward a stated objective.2
  • Per MetaRestart-safe. Every model call, tool run, approval and edit goes into a local event log, so a session can resume after a crash.2
  • Per MetaExtensible with subagents, skills, hooks and MCP servers.1

How to install and sign in

  1. InstallmacOS or Linux: curl -fsSL https://dev.meta.ai/install.sh | sh. Windows (PowerShell): irm https://dev.meta.ai/install.ps1 | iex.1
  2. Start itRun muse in your project folder.3
  3. Sign inEither approve the session in your browser, or set an API key with export META_API_KEY="…" or muse auth set. Meta Managed Accounts must use an API key.3
  4. BillingFor teams, an admin adds a payment method and creates an API key before Muse Code can be used.3

Only install from dev.meta.ai. Several look-alike “Muse Code” sites aren’t Meta’s.

On Windows, Meta’s docs note a few differences: PowerShell replaces Bash, and voice input and session messaging aren’t supported.1

What it costs

Meta Model API prices per 1 million tokens (checked 2026-10-02)
TierInputOutputYour data
Standard$1.25$4.25Not used to train Meta models
Contributor$0.10$0.20Meta may use prompts and completions to train future models

Per MetaPrices and data terms are from Meta’s pricing docs.4 Meta’s Muse Code docs describe four flat-rate subscriptions: “Everyday Usage,” “High Usage” (5× more), “Power Usage” (20× more) and “Maximum Usage” (80× more).5 ReportedFelloAI, citing Meta’s Muse Code page, lists them at $5, $15, $50 and $200 a month. Since October 12, 2026, Muse Code includes Meta’s new Muse Wonder, and the Power and Maximum plans add Muse Wonder Full. Muse Wonder. We found no free tier. If your code is confidential, don’t use the Contributor tier.

Approvals and sandbox

Per MetaShell commands run inside an OS-enforced sandbox that limits file writes and network access; if the sandbox can’t enforce its limits, the command doesn’t run.6 On top of that, an approval mode decides what needs your OK:

on-request
The default. Recognized, non-dangerous commands usually pass; risky ones ask.
untrusted
Stricter: stops any shell command without a matching allow rule.
never
No approvals; only the sandbox contains what runs.

When it asks, you can Allow once, Always allow in this workspace (which saves a rule) or Reject. Deny rules always win over allow rules. Meta warns to use --yolo only in an already-isolated environment, “never on workstations with real credentials or infrastructure access.”6

Which model it uses

Per MetaMeta’s Muse Code docs name muse-spark-1.2 as the default model.1 Meta says Muse Spark 1.3, released September 2, 2026, is also available in Muse Code, including with “max reasoning.”7 Versions and benchmarks are in Muse Spark explained.

Muse Code vs the Muse app

Two different Meta products
 Muse (app)Muse Code
ForEveryday personal and business tasksSoftware development
RunsOn Meta’s cloud computer; you chat on phone, web, Mac or WhatsAppIn your terminal or CI, on your machine
Pay withMuse plans: free, $20 or $100/monthMeta Model API billing
WhereUS and CanadaNot stated in the docs we read

Sources

  1. Muse Code overview Meta developer docs · checked Oct 2, 2026
  2. Introducing Muse Code and Muse Spark 1.2 Meta AI Research · Aug 5, 2026
  3. Muse Code installation and authentication Meta developer docs
  4. Pricing and rate limits Meta Model API docs · checked Oct 2, 2026
  5. Muse Code subscriptions Meta developer docs
  6. Muse Code permissions and safety Meta developer docs
  7. Introducing Muse Spark 1.3 Meta AI Research · Sept 2, 2026

Last checked: 2026-10-02. Developer tools change fast. Spotted a change? Tell us.

Frequently asked questions

Is Muse Code the same as Muse?

No. Muse is Meta’s personal agent app for everyday tasks. Muse Code is a separate coding agent for developers that runs in your terminal or CI. Both use Meta’s Muse Spark models.12

How do I install Muse Code?

On macOS or Linux, Meta’s docs give curl -fsSL https://dev.meta.ai/install.sh | sh; on Windows, irm https://dev.meta.ai/install.ps1 | iex in PowerShell. Then run muse and sign in through your browser, or set an API key.13

Is Muse Code free?

We found no free tier in Meta’s docs. Usage is billed through the Meta Model API by tokens (Standard: $1.25 per million input tokens, $4.25 per million output), and the docs also describe flat-rate subscription plans without public prices.45

Does Meta train on my code?

It depends on the model tier. On the Contributor tier, Meta’s docs say you give Meta permission to use your prompts and completions to train future models; on Standard, they aren’t used for training.4