The amux status line

Claude Code draws one line under the prompt box, and lets a script decide what goes on it. amux-statusline is that script, built for running many sessions at once under amux: every session says which one it is, where it runs, what it bills, and how much room it has left.

 4  laptop:…/api ○  T  Op5⁵ hi · ctx 82% · in 36k · Σ251k · ⎇ feat/login* · 7d 75% 2d 7h · 5h 61% 3h 29m ↻

It is optional. amux works the same without it.

Install

./install.sh --statusline        # from the checkout, together with everything else
amux-statusline --install        # or later, on its own

Either one writes a statusLine entry into ~/.claude/settings.json that points at the amux-statusline command in ~/.local/bin, so git pull in the checkout updates it. It takes effect on the next render; no restart needed.

• A backup is made first: ~/.claude/settings.json.bak-amux-<date>.
• If you already have a status line, it stops and shows it. amux-statusline --install --force replaces it (still with a backup).
• amux-statusline --uninstall removes the entry, but only if it is still this one. ./install.sh --uninstall does that for you.

Needs python3. git is used for the branch segment only; without it, the branch is simply never shown.

What each part means

A few details:

• Branch from the session root. The branch comes from the directory the session started in, not wherever a command last cd’d to. When the session root holds several repositories but is not one itself, it lists the first one that is off its default branch, plus how many more (⎇ app:feat/x +1).
• Quotas appear only on Pro/Max plans, and only after the session’s first reply.
• Tab titles. Inside tmux it also renames the window to name (O hi) (model initial and effort), so tab titles in iTerm2 and other terminals show them.

Narrow panes

When the line does not fit, parts go in this order: branch, then the directory (leaving only the machine name), Σ, 7d, 5h, in, ctx. The session square, machine, focus view, account and model always stay, and so does ↻. Below 100 columns Σ is left out even when it would fit.

Settings

All optional, in ~/.config/amux/statusline.conf, one per line:

# fix the color of a machine whose name contains "desk" (xterm-256 color number)
color desk 208
# show "desk01" instead of "lab-desk01"
strip-prefix lab-
# append each 5h / 7d quota reading to ~/.claude/quota.log (at most once a minute per account)
quota-log on

Without a color line, each machine gets a color picked from its name, the same on every render. AMUX_STATUSLINE_CONF=<file> points at a different file.

Terminals

I use it daily in iTerm2 on macOS, and it works the same in Linux terminals. A terminal needs:

• 256 colors: any modern terminal, and tmux with the default TERM settings.
• A font with the symbols ◉ ○ ⎇ Σ ↻ and superscript digits. Most current monospace fonts have them.
• In iTerm2, leave “Treat ambiguous-width characters as double width” off, or the line is measured wrong and gets cut early.

When it looks wrong

• Blank line. Run it by hand with a sample, and any Python error shows: echo '{"model":{"display_name":"Opus 5.5"}}' | amux-statusline
• No square number. The session is not an amux session, or was started outside amux.
• Different from someone else’s. Check you are both on the same checkout version (cat VERSION).