Telemetry

Claude Code calls a custom statusline command every turn with a JSON payload on stdin. The payload includes the current context-window fill percentage, model, cost, and cwd. Nothing in the contract says you can only read it — you can fork it to anything you want, and the command stays a statusline. (Quick framing for anyone new to Claude Code: it’s Anthropic’s terminal CLI for Claude, and the statusline is the configurable line of text it prints under your prompt every turn — like a shell prompt for the agent. You point at any script in settings.local.json, Claude pipes a JSON object to it on stdin, and whatever the script writes to stdout becomes the visible line.)