ctxline mine

Why

I wrote it because every status line I saw either printed nothing I needed or printed ten things I didn't. The one fact that changes what I do next is how full the context window is, so that's the only number on the line:

Opus 5 · 40k/1M

The count is colored by pressure — green normally, yellow past 60%, bold rose past 85%. The model name is deliberately the quietest thing there: it changes at most once a session, so color on the line means exactly one thing, which is how much room is left.

It's Rust for one reason. Claude Code cancels an in-flight status line script when a new update arrives, so startup time is the only property that matters — a Node or Python script pays its interpreter boot on every assistant message and loses the race. The binary is ~330KB and runs in about 3ms. Claude Code already pipes a JSON payload containing a context_window object, so this is a pure stdin → stdout filter: no transcript parsing, no subprocesses, no I/O of its own.

Setup

curl -fsSL https://raw.githubusercontent.com/serhiileniv/ctxline/main/install.sh | sh

Downloads the binary into ~/.local/bin, points ~/.claude/settings.json at it, and backs that file up first if it already existed.

Watch out for

settings.json is read at startup. Restart Claude Code after installing or the line won't change.