/tags/telemetry/ Recent content in Telemetry on Nick Liu - Software Engineer Hugo -- gohugo.io en nickboy@users.noreply.github.com (Nick Liu) nickboy@users.noreply.github.com (Nick Liu) 2026 Nick Liu Sun, 10 May 2026 22:48:37 -0700 /posts/statusline-side-channel/ Sun, 10 May 2026 00:00:00 +0000 nickboy@users.noreply.github.com (Nick Liu) /posts/statusline-side-channel/ <div class="lead text-neutral-500 dark:text-neutral-400 !mb-9 text-xl"> 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. </div> <p>(Quick framing for anyone new to Claude Code: it&rsquo;s Anthropic&rsquo;s terminal CLI for Claude, and the <em>statusline</em> 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 <code>settings.local.json</code>, Claude pipes a JSON object to it on stdin, and whatever the script writes to stdout becomes the visible line.)</p>