implementation-planning

# Implementation Plan Skill

Creates actionable implementation plans that break features into executable tasks following TDD principles. Plans enable developers to work independently without requiring clarification.

## Success Criteria

A plan is complete when:
- [ ] A developer can follow it independently without additional context
- [ ] Every task produces a verifiable deliverable (not just an activity)
- [ ] All PRD acceptance criteria map to specific tasks
- [ ] All SDD components have corresponding implementation tasks
- [ ] Dependencies are explicit and no circular dependencies exist

## When to Activate

Activate when:
- **Create a new PLAN** from the template
- **Complete phases** in an existing implementation-plan.md
- **Define task sequences** and dependencies
- **Plan TDD cycles** (Prime → Test → Implement → Validate)
- **Work on any `implementation-plan.md`** file in docs/specs/

## Template

The PLAN template is at [template.md](template.md). Use this structure exactly.

**To write template to spec directory:**
1. Read the template: `plugins/start/skills/implementation-plan/template.md`
2. Write to spec directory: `docs/specs/[NNN]-[name]/implementation-plan.md`

## PLAN Focus Areas

Your plan MUST answer these questions:
- **WHAT** produces value? (deliverables, not activities)
- **IN WHAT ORDER** do tasks execute? (dependencies and sequencing)
- **HOW TO VALIDATE** correctness? (test-first approach)
- **WHERE** is each task specified? (links to PRD/SDD sections)

Keep plans **actionable and focused**:
- Use task descriptions, sequence, and validation criteria
- Omit time estimates—focus on what, not when
- Omit resource assignments—focus on work, not who
- Omit implementation code—the plan guides, implementation follows

## Task Granularity Principle

**Track logical units that produce verifiable outcomes.** The TDD cycle is the execution method, not separate tracked items.

### Good Tracking Units (produces outcome)
- "Payment Entity" → Produces: wo