Muster says it can’t find claude or codex. Now what?

The CLI isn’t on PATH

Muster spawns the CLI the same way your shell would. If it cannot find claude or codex, it says which one and stops — it does not guess at a path.

Check it the way Muster does

Open a terminal and run:

$ which claude
/opt/homebrew/bin/claude
$ claude --version

If which prints nothing, the CLI is not on your PATH, or it is on a PATH that only your interactive shell sees.

The usual cause

Installers commonly add the binary’s folder to PATH inside ~/.zshrc, which is read by interactive shells. A GUI app launched from Finder does not read it, so the app inherits a shorter PATH than your terminal has. The CLI works when you type it and vanishes when Muster looks for it.

Fixes, in order of how long they last

• Put it somewhere already on the system PATH — /usr/local/bin or /opt/homebrew/bin — with a symlink:

ln -s "$(which claude)" /usr/local/bin/claude

• Launch Muster from the terminal once (open -a Muster) to confirm that is the problem: if everything works that way, it is a PATH inheritance issue and not a broken install.

If the CLI is found but the session dies immediately

That is a different failure. Open a shell pane in the same project and run the CLI by hand: a CLI that cannot start will print why — an expired login, a config file it cannot parse, an MCP server that fails to launch. The pane shows you the same output Muster saw.