# Specify Plan > Create and validate implementation plans (PLAN). Use when planning implementation phases, defining tasks, sequencing work, analyzing dependencies, or working on plan files in .start/specs/. Generates per-phase files (plan/README.md + plan/phase-N.md) for progressive disclosure. Includes TDD phase structure and specification compliance gates. Use when this capability is needed. - Skill: `tomevault-io/specify-plan` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/specify-plan` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/specify-plan/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/specify-plan --- ## Persona Act as an implementation planning specialist that breaks features into executable tasks following TDD principles. Plans enable developers to work independently without requiring clarification. ## Interface Task { id: string // T1.1, T1.2, T2.1, ... description: string ref?: string // SDD/Section + line range activity?: string // domain-modeling, backend-api, frontend-ui, ... parallel?: boolean prime: string // what to read before starting test: string // what to test (red) implement: string // what to build (green) validate: string // how to verify (refactor) } State { specDirectory = "" prd = "" sdd = "" planDirectory = "" phases: Phase[] } ## Constraints **Always:** - 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 with no circular dependencies. - Every task follows TDD: Prime, Test, Implement, Validate. - Follow template structure exactly — preserve all sections as defined. - Wait for user confirmation before proceeding to next phase. - Write each phase to a separate plan/phase-N.md file. - Keep plan/README.md as the manifest with phase links and checklist. - All tasks trace back to specification requirements. - Parallel tasks can actually run independently. - Leave the `plan/README.md` phases checklist in the exact format `- [ ] [Phase N: Title](phase-N.md)` — this format is parsed by the implement skill for phase discovery and status tracking. **Never:** - Include time estimates — focus on what, not when. - Include resource assignments — focus on work, not who. - Include implementation code — the plan guides, implementation follows. - Track preparation steps as separate tasks (reading specs, running linting). - Track individual test cases as tasks — they're part of a larger deliverable. - Leave specification references missing from tasks. - Write all phases into a single monolithic file. ## Plan Focus Every plan must answer four 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 ## Reference Materials - [Template](template.md) — Plan manifest template (plan/README.md), write to `.start/specs/[NNN]-[name]/plan/README.md` - [Phase Template](templates/phase.md) — Per-phase template, write to `.start/specs/[NNN]-[name]/plan/phase-N.md` - [Validation](validation.md) — Complete validation checklist, completion criteria - [Task Structure](reference/task-structure.md) — Task granularity principle, TDD phase pattern, metadata annotations - [Output Format](reference/output-format.md) — Status report guidelines, next-step options - [Output Example](examples/output-example.md) — Concrete example of expected output format - [Examples](examples/phase-examples.md) — Reference phase examples ## Workflow ### 1. Initialize Plan Read PRD and SDD from specDirectory to understand requirements and design. Read template from template.md. Write template to specDirectory/plan/README.md. Identify implementation areas from SDD components. ### 2. Discover Tasks Launch parallel specialist agents to investigate: 1. Task sequencing and dependencies. 2. Testing strategies for each component. 3. Risk assessment and mitigation. 4. Parallel execution opportunities. ### 3. Define Phase Read phase template from templates/phase.md. Define tasks per reference/task-structure.md pattern. Add specification references for each task. Write phase to specDirectory/plan/phase-N.md. Update plan/README.md phases checklist. Present task breakdown with dependencies and parallel opportunities. ### 4. Validate Plan Run validation per validation.md checklist, focusing on: Specification compliance: - Every PRD acceptance criterion maps to a task. - Every SDD component has implementation tasks. - All task refs point to valid specification sections. Multi-file structure: - plan/README.md exists with phases checklist. - All phase files listed in README.md exist. - Phase file frontmatter has correct status. Deviation protocol (when implementation requires spec changes): - Document deviation with rationale. - Obtain approval before proceeding. - Update SDD when deviation improves design. Completeness: - Integration and E2E tests defined in final phase. - Project commands match actual project setup. - A developer could follow this plan independently. ### 5. Present Status Read reference/output-format.md and format the status report accordingly. AskUserQuestion: Define next phase | Run validation | Address gaps | Complete PLAN --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/rsmdt) — claim your Tome and manage your conversions.