Plan

Before non-trivial implementation, produce a plan the user can sanity-check. This catches bad assumptions early and reduces rework.

When to use

• Multi-file features or refactors.
• Anything with >3 steps or unclear scope.
• When the user says "plan this out" / "how would you approach …".

Procedure

1. Understand the goal. Restate it in one sentence. If ambiguous, ask a focused question (use the clarify tool) before planning.
2. Survey the relevant code. Read the files/areas that will change. Ground the plan in real symbols and paths, not guesses.
3. Produce a sequenced plan:
   • Ordered steps, each with: what changes, which files, and the verification for that step.
   • Flag decisions/risks and unknowns explicitly.
   • Note what is deliberately out of scope.
4. Propose the plan for sign-off before implementing. Don't start editing until the user agrees (unless the task was explicitly "just do it").
5. Track progress with the todo tool as you implement; update statuses as steps complete.

Good plan properties

• Concrete: names files and functions, not "update the auth module".
• Ordered: step N doesn't depend on step N+2.
• Verifiable: each step has a check (test, typecheck, manual repro).
• Scoped: explicit out-of-scope list prevents scope creep.

Output shape

Goal: <one line>

Steps:
1. <file/symbol> — <change>. Verify: <how>.
2. …

Out of scope: …

Risks / decisions: …

Prefer the smallest plan that achieves the goal; split large plans into phases.