Project Plan Feature

Use this skill only when explicitly invoked as $project-plan-feature. It owns
Gate 4 planning for one feature at a time and updates only the corresponding
milestone-status.txt.

Core Rules

• Read progress.txt and the active milestone-status.txt fresh from disk.
• Require at least one milestone directory with milestone-status.txt.
• Write only milestone-status.txt; do not update progress.txt.
• Produce the feature plan, present it for review, and record approval only after
  checklist items are [x] or [-] with a reason.
• Read spike docs only when the user explicitly references them.
• Ask concise chat questions for user choices; use structured input tools when
  available.
• Do not invoke the next skill automatically. Recommend the next explicit skill.
• Read the referenced workflow files before executing their corresponding steps;
  they contain required edge-case handling, review criteria, and artifact formats.

Workflow

1. Auto-detect the active milestone from progress.txt or use the user's explicit
   milestone override.
2. Read the milestone status file and choose the first pending feature, unless
   the user names another feature.
3. Normal mode: read references/gate-4-plan.md, load required inputs, perform a
   targeted codebase scan, and create
   milestones/<NN>-<name>/plans/<feature>.md using
   assets/feature-plan-template.md.
4. Re-plan mode: read references/revision-mode.md, load the existing plan, ask
   what changed, and apply focused revisions.
5. Create/update the Gate 4 review file using
   references/review-checklist-template.md.
6. Update the feature entry in milestone-status.txt to [~] planned, awaiting build with the plan path.

Reference Files

• references/gate-4-plan.md
• references/revision-mode.md
• references/progress-format.md
• references/review-checklist-template.md
• assets/feature-plan-template.md

Completion

Report created/updated artifacts and recommend $project-build for a planned
feature or $project-plan-feature for the next pending feature.