Ullage — Development skill for Claude Code

Ullage watches your Claude Code and OpenAI Codex CLI session transcripts, keeps every API call in a local SQLite database, and shows the context window's fill level as a percentage in the macOS menu bar. It also lists Cursor agent activity, though Cursor records no token counts locally so it has no fill percentage. Click it to break the current session down turn by turn and see what is actually taking up the window. A separate history window charts your activity across days and projects.

Everything stays on your machine. Nothing is uploaded.

**Ullage** — the empty space left at the top of a barrel or tank. Here, the room still left in the context window.

What it looks like

• Menu bar: a gauge icon whose needle rises with occupancy, followed by the percentage   . It turns amber past 85%, and drops to a plain gauge with no number once a session has been idle for 30 minutes, so a stale figure is never mistaken for a live one.
• Popover — click the menu bar item for:
  • the active project, model, and headline percentage;
  • a session picker that follows the most recently active session, or pins one so it holds still while others are talking;
  • a chart of context tokens per turn, with the window as the ceiling, the 85% line, and a marker wherever a compaction dropped the window (hover for the exact turn, tokens, and chan