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, and you can fork it to anything you want while the command stays a statusline. Building ClaudeDeck · Part 4 of 10 1 2 3 4 5 6 7 8 9 10 🧪 Tested with Claude Code 2.1.x · macOS (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.)