Write a project-root HANDOFF.md that preserves active work across a context rollover or fresh coding session. Use when context usage is high, a rollover warning appears, or the user asks to hand off, roll over, clear, or continue the work in a new Claude Code or Codex session.
Use when the user asks for caveman mode, fewer tokens, terse mode, or very compressed technical communication.
Review a GitHub PR locally. Use for PR numbers, local PR reviews, or review prompts; inspect diff and comments first, use temporary worktrees/checks only when needed, and return copyable Markdown.
Use when the user wants a plan, design, architecture, or decision stress-tested with direct questions.
Use when starting a new software project, shaping a fresh repository, choosing initial architecture, defining the first implementation slice, or turning a product idea into an executable engineering kickoff plan.
Use when onboarding to an unfamiliar repository or explaining what a repo is, what it does, how it is structured, how to run it, and where to start contributing.
Use when reviewing architecture, finding module boundaries, improving testability, or identifying refactor opportunities in a codebase.
Use when fixing a bug, regression, failing test, or reported broken behavior.