Claude HUD Data Pipeline

How Claude Code feeds real-time session state into the statusline every 300ms

DATA SOURCES Claude Code stdin model, context_window, cwd Transcript JSONL tools, agents, todos, session Anthropic Usage API 5h/7d utilization, plan name Git Status branch, dirty, ahead/behind Config + Counters CLAUDE.md, rules, MCPs, hooks main() Assemble RenderContext render() Layout + ANSI output $ claude [ Opus | Max ] | my-project git:(main*) Context █████ ░░░░░ 45% | Usage ██ ░░░░░░░░ 25% --- optional lines --- Edit: auth.ts | Read x3 | Grep x2 explore [haiku]: Finding auth code (2m 15s) Fix authentication bug (2/5) Claude > _ ───────────────────────────────── JSON stream cached RenderContext stdout
Interactive Diagram: Hover over components to see details, or use the buttons to trace data through the pipeline.