🔋 Claude & Codex Usage Battery

A macOS menu bar widget that shows your remaining Claude Code and Codex usage limits as battery icons — so you never have to open /usage again.

C = Claude · X = Codex. Each battery shows the remaining % of a limit window — full & green means plenty left, red means almost out. Click for a detailed breakdown with reset times.

Built as a single SwiftBar plugin — one self-contained script, no third-party libraries. The battery icons are rendered as PNGs from scratch in pure JavaScript (node:zlib only), so there's no image library and no npm install. The only network call is an optional once-a-day update check (see Updating) — disable it and the widget makes none at all. (ccusage is an optional extra for the cost breakdown.)

What it shows

Click the widget for a dropdown with, per limit:

Claude Code
  5h remaining   ▕██████████████░░░░░░▏ 70%  (used 30%)  · resets 3h 18m
  weekly         ▕██████▋░░░░░░░░░░░░░▏ 33%  (used 67%)  · resets 3d 21h
  Fable          ▕████░░░░░░░░░░░░░░░░▏ 26%  (used 74%)  · resets 3d 21h
  today by model ▕████████████▏ Fable $75 · Opus $46 · Sonnet $5 …

Codex · prolite
  5h remaining   ▕████████████████████▏ 100% (used 0%)
  weekly         ▕████████████████▋░░░▏ 83%  (used 17%)

Colors follow a traffic-light scale: green ≥ 50 % left, amber < 50 %, red < 20 %.

Requirements

Note: This widget reads your own local usage files. If you don't use Claude Code (or Codex), there simply won't be any data to display.

Install

git clone https://github.com/dennykim123/claude-codex-battery.git
cd claude-codex-battery
./install.sh

install.sh will:

1. Verify bun and SwiftBar are present (and tell you how to install them if not)
2. Copy the plugin into ~/.swiftbar-plugins/, rewriting the shebang to your machine's bun path (SwiftBar runs plugins with a minimal PATH, so an absolute shebang is required)
3. Point SwiftBar at the plugin folder and launch it

No npm install, no bundled libraries — the plugin is a single self-contained script.

The battery appears in your menu bar within a few seconds. It refreshes every 2 minutes (the .2m. in the filename).

Manual install

If you prefer not to run the script:

mkdir -p ~/.swiftbar-plugins
# rewrite shebang to your bun path, then copy:
sed "1s|.*|#!$(command -v bun)|" claude-codex-usage.2m.js > ~/.swiftbar-plugins/claude-codex-usage.2m.js
chmod +x ~/.swiftbar-plugins/claude-codex-usage.2m.js
defaults write com.ameba.SwiftBar PluginDirectory -string ~/.swiftbar-plugins
open -a SwiftBar

Updating

The widget checks GitHub for a newer version at most once a day — a tiny background request that is the only network call it ever makes. When a new version is out, a green 🆕 update row appears in the dropdown; click it to replace the plugin in place and refresh (your previous copy is kept as .bak).

Prefer to do it yourself? From your clone: git pull && ./install.sh.

To turn the check off entirely, comment out the getUpdateInfo() call near the bottom of the script — then the widget makes zero network calls.

Privacy & security

• No usage data leaves your machine. Limits are read from local files and rendered locally; the only network call is the optional daily update check above.
• No secrets read. It never touches auth.json, credentials, or keychains.
• No conversation content. From Codex session logs it parses only the rate_limits object (numbers), never the messages.
• Usage values are read at runtime — nothing is baked into the code, so sharing the script shares no data.

How accurate / in-sync is it?

Claude — effectively real-time. The limits come from usage-cache.json, the same rate-limit data Claude Code uses for its own /usage. The widget just reads that file (every 2 min), so its numbers track Claude's. Measured on a live machine: the widget's weekly and Fable readings matched the source file exactly; the 5-hour figure differed only by the live drift between two reads a minute apart.

Codex — as fresh as your last Codex run. Codex writes rate-limit data to its session logs only while you use it, and records no reset time. So the value is a snapshot from your most recent session — the dropdown labels it "measured N ago" and warns past 3h. Run Codex and it re-syncs instantly.

TL;DR — Claude is live (same source as /usage); Codex is a clearly-labeled snapshot from your last session, not a live feed.

How it works

The whole thing is one .js file run by bun on a timer.

• Battery icons are drawn pixel-by-pixel into an RGBA buffer and encoded to PNG using only node:zlib (hand-rolled CRC32 + IHDR/IDAT/IEND chunks). A 5×7 bitmap font renders the numbers and the C/X group labels. SwiftBar displays the PNG at pixels ÷ 2 pt.
• Claude limits come from usage-cache.json, which Claude Code keeps current. The Fable cap is the weekly_scoped entry.
• Codex limits come from the newest session's rate_limits. The premium plan reports a credits object instead of percentages when exhausted; the widget handles both shapes.

Codex has one quirk

Codex only writes limit data to session logs while you use it, and doesn't record a reset time when exhausted. So if you haven't run Codex in a while, the value can be stale. The widget:

• flags values older than 3 hours in the dropdown, and
• optionally runs codex exec --sandbox read-only in the background to refresh — but only when Codex is exhausted and the value is 2h+ old, at most once every 6 hours (≈4×/day, ~20k tokens each).

If you'd rather it never spend tokens on its own, comment out the maybeAutoRefreshCodex(codex) call near the render section.

Customizing

Why a SwiftBar plugin (and not a standalone app)?

A single script stays dependency-free, easy to audit, and trivial to fork — and its audience (Claude Code / Codex developers) already lives in the terminal, so brew install swiftbar is no barrier. A native .app would drop the SwiftBar requirement but adds a Swift codebase, Apple code-signing + notarization ($99/yr), and ongoing maintenance. Roadmap: if there's enough demand, ship a signed one-click menu-bar .app (likely bundling SwiftBar) for non-terminal users.

Contributing

Issues and PRs welcome — especially for other plans/tools (e.g. mapping additional rate_limit shapes, or adding providers). Keep it dependency-free.

License

MIT