writing-plans

Use when an approved spec / requirements doc exists and needs to become a bite-sized, TDD-structured implementation plan — prose markdown at `docs/plans/YYYY-MM-DD-<feature>.md` plus a YAML sidecar when the plan has ≥3 tasks, a human gate, or a loop. Trigger phrases: "write the implementation plan for this spec", "turn this design into tasks", "break this feature into TDD steps", "plan out how to build X from the spec", "I have a spec — what's the plan", "create the plan document", "scaffold tasks for this design", "give me a bite-sized plan", "convert the approved design into a plan", "plan the implementation of <feature>". Runs the plan-document reviewer loop and hands off to subagent-driven-development or executing-plans. Do NOT use when there is no approved spec yet (use brainstorming first), when executing an existing plan (use subagent-driven-development or executing-plans), or for single-edit bugfixes that don't need a multi-step plan.