Muse Code Not Working? Fixes for Every Common Error

Symptoms plus 401 and 403 behaviour were read from the published Muse Code launcher on 6 August 2026, during beta.

muse: command not found

Most reports of Muse Code not working after install trace back to this. The installer writes one binary to ~/.local/bin/muse and appends a PATH line to your shell profile; three things break that chain.

• PATH was never reloaded. Your shell started before the profile was edited. Open a new terminal or run exec $SHELL -l.
• ~/.local/bin is not on PATH. Some setups strip it — check echo $PATH.
• MUSE_NO_MODIFY_PATH was set. That variable tells the installer to leave your profile alone, so no line was written.

ls -l ~/.local/bin/muse
echo $PATH
export PATH="$HOME/.local/bin:$PATH"

If ls shows the file, Muse Code installed fine and only resolution is broken — do not reinstall. Check what you typed, too: the command is muse, never muse-code. If you set MUSE_INSTALL_DIR, look there. Full sequence: how to install Muse Code.

Muse Code installed but nothing happens in the terminal

Community reports suggest the command sometimes accepts input and then appears to do nothing; this variant of Muse Code not working has no confirmed cause. Run which muse to confirm which binary you are invoking, and check you are in an interactive terminal — Muse Code expects a real TTY.

On first run Muse Code starts a device-style OAuth flow against auth.meta.com: it prints a verification link, tries to open your browser, then polls until you approve. Approval is read from /dev/tty, so any environment without a terminal or a browser breaks the loop.

Muse Code sign in fails inside a Docker container

This is the best-documented case of Muse Code not working; the Cline team reported hitting it publicly on launch day. A container shell usually has no /dev/tty and no browser, so the poll never completes even though Muse Code installed cleanly.

• Allocate a TTY. docker run -it at least gives the flow a terminal to read from.
• Open the printed link yourself. The verification URL appears before the browser attempt, so approve it on your host.
• Sign in on the host. Where the container is only a build sandbox, that is the reliable path.

Meta has published no documented container workflow, so treat these as workarounds and watch Meta's developer site for changes during beta.

The browser never opens (WSL and remote shells)

Under WSL2 the Linux binary must hand its verification URL to a Windows browser, and that hand-off is where Muse Code not working shows up most. Over SSH there is no local browser at all. The WSL route is on Muse Code on Windows.

403: muse is available to Meta employees

That exact string sits in the Muse Code launcher — a leftover from the internal-access gate that shipped alongside the public beta. Your request reached Meta and was refused at the access check, so Muse Code is not broken.

No user-side fix is confirmed, and the gate is server-side, so reinstalling changes nothing. Confirm you signed in with the account registered on dev.meta.ai and that your region is eligible.

401: the token expired

A 401 is ordinary expiry rather than refusal. The stored credential is stale, and re-running Meta's installer restarts the sign-in flow; Muse Code works again once browser approval completes.

curl -fsSL https://dev.meta.ai/install.sh | bash

If a fresh sign-in returns straight back to 401, stop retrying: that is an account problem, not a client one.

Payment method required before Muse Code will run

Muse Code has no free tier and no monthly plan. Billing is pure per-token usage, so a card must be on file before the agent does useful work, and an unbilled account produces a wall that reads like a broken install. Reported rates are on Meta's pricing and rate limits page; tiers on Muse Code pricing.

The Contributor tier is unavailable in your country

Contributor is limited to a subset of countries, so an account elsewhere only sees Standard pricing — a policy limit, not a fault. Contributor also grants Meta training rights over your prompts and completions, so read what Meta does with your code before switching on price alone.

• Network reach. The installer talks to dev.meta.ai and pulls the binary from lookaside.facebook.com; proxies blocking Meta-owned hosts break downloads and sign-in with no obvious error.
• Platform. Muse Code ships for macOS and Linux on arm64 and x86_64 only, and the launcher exits on anything else.
• Beta churn. Released 5 August 2026, so behaviour moves. Meta's launch post and the Muse Spark model page are where to re-check; the Hacker News thread is where early reports surfaced.

If Muse Code runs but disappoints rather than errors, see what Muse Code is for what the agent is built to do.

• How to Install Muse CodeThe clean install path, PATH variables and verification.
• Muse Code on WindowsWSL2 setup and the browser hand-off that breaks sign-in.
• Muse Code PricingWhy a payment method is required first.
• Muse Code AlternativesWhere people go when the access gate does not lift.