Implementation Planner

Implementation Planner

Overview

Generate execution-ready, coding-only implementation plans from research documents. The goal is to produce plans that any JR developer can execute immediately with zero ambiguity.

North Star Rule

If a JR developer picked this up, could they start coding immediately?

If the answer is "no" or "they'd need to ask clarifying questions," the plan is incomplete.

When to Use

• User asks to "create a plan from research"
• User references a research doc in memory-bank/research/
• User wants "implementation steps" from findings
• User asks to "break down into tasks" a researched topic

What This Skill Does NOT Do

Planning Workflow

1. Read Research Doc

Read from: memory-bank/research/<topic>.md
Extract: scope, constraints, target files, unresolved questions, proposed solutions

2. Verify Git Freshness

# Capture current state
git rev-parse HEAD          # Commit SHA
git status --short          # Working tree status

3. Generate Plan File

Save as: memory-bank/plan/YYYY-MM-DD_HH-MM-SS_<topic>.md

4. Plan Structure

---
title: "<topic> – Implementation Plan"
phase: Plan
date: "{{timestamp}}"
owner: "{{agent_or_user}}"
parent_research: "memory-bank/research/<file>.md"
git_commit_at_plan: "<short_sha>"
tags: [plan, <topic>, coding]
---

## Goal

- ONE singular coding-focused outcome
- Explicitly state what is OUT of scope (ops, deploy, excessive testing)

## Scope & Assumptions

- IN scope: (technical items only)
- OUT of scope: (what we're NOT doing)
- Assumptions: (frameworks, environments, libraries)

## Deliverables

- Source code modules, functions, or APIs
- Documentation limited to developer-level notes (not user docs)

## Readiness

- Preconditions: repos, libs, data schemas, sample inputs
- What must exist before starting

## Milestones

- M1: Skeleton & architecture setup
- M2: Core logic & data flow
- M3: Feature completion & refinement
- M4: Basic test(s) & integration hooks

## Work Breakdown (Tasks)

For EACH task, specify:
- **Task ID**: T001, T002, etc.
- **Summary**: What to do (present tense, actionable)
- **Owner**: who does it
- **Estimate**: time/complexity
- **Dependencies**: other task IDs
- **Target milestone**: M1-M4
- **Acceptance test**: Exactly ONE test that proves it works
- **Files/modules touched**: List exact paths

## Risks & Mitigations

Keep technical:
- Library stability issues
- API version drift
- Schema mismatch risks
- Breaking changes in dependencies

## Test Strategy

At most ONE new test per task, only for validating main coding work.
Focus on proving correctness, not coverage.

## References

- Research doc sections
- Key code references (file:line format)

## Final Gate

- **Output summary**: plan path, milestone count, tasks ready
- **Next command**: `/use plan-executor "<plan_path>"`

Task Writing Guidelines

✅ Good Task

T003: Add user authentication middleware
- Create src/middleware/auth.ts with verifyToken() function
- Import in src/app.ts and apply to /api/* routes
- Acceptance: curl /api/users returns 401 without header, 200 with valid token
- Files: src/middleware/auth.ts, src/app.ts
- Milestone: M2

❌ Bad Task

T003: Fix auth
- Handle the auth stuff properly
- Make sure it works

Rules for Tasks

1. Present tense, actionable: "Add function X" not "Function X should be added"
2. File paths explicit: No "find the right place to put it"
3. One acceptance test per task: Single proof of correctness
4. No hand-waving: "Implement caching" → "Add Redis caching to src/cache.ts with get/set methods"
5. Depend on tasks, not people: "Depends on T001" not "Wait for backend team"

Git Freshness Check

Always capture and include:

COMMIT_SHA=$(git rev-parse --short HEAD)
STATUS=$(git status --short)

If research doc mentions specific commits/branches and they've changed:

• Mark affected tasks for re-verification
• Note the discrepancy in plan frontmatter

Issue Opening (When Available)

If planning reveals blockers or prerequisites that need tracking:

• Check for Gitea/GitHub availability
• Open issues ONLY for:
  • External dependencies
  • Prerequisites that aren't in scope
  • Decisions needed before execution
• Link issue IDs to relevant tasks

Validation Questions

Before finalizing, ask:

1. Ambiguity check: Could a JR developer understand every task without questions?
2. Completeness: Are all prerequisites and dependencies listed?
3. Executability: Does each task specify exact files and acceptance criteria?
4. Scope creep: Is ops/deploy work leaking into the plan?

Output Format

After plan generation, output:

✓ Plan written to: memory-bank/plan/YYYY-MM-DD_HH-MM-SS_<topic>.md
✓ Milestones: 4
✓ Tasks: 12
✓ Git state: <short_sha>

Next: /use plan-executor "memory-bank/plan/YYYY-MM-DD_HH-MM-SS_<topic>.md"

Examples

Example Plan Entry

## Task T004: Add rate limiting to API endpoints

**Summary**: Implement token-bucket rate limiting for public API endpoints

**Files**:
- src/middleware/rateLimit.ts (new)
- src/app.ts (modify)

**Changes**:
1. Create src/middleware/rateLimit.ts with TokenBucket class
   - Constructor takes capacity and refillRate
   - consume(tokens) method returns true if allowed
2. Add rateLimit instance to src/app.ts
3. Apply to /api/public/* routes only

**Acceptance Test**:
- Send 100 requests in 1 second to /api/public/data
- First 60 succeed (200)
- Next 40 fail (429)
- Headers include X-RateLimit-Remaining

**Dependencies**: T001 (Express app setup)
**Milestone**: M2
**Estimate**: 2 hours

Subagent Usage (Sparingly)

Only spawn subagents if:

• Research doc is large (>500 lines)
• Need to map tasks to existing codebase structure
• Need parallel analysis of multiple subsystems

Typical subagents:

• codebase-analyzer: Find where new code fits
• context-synthesis: Extract structured tasks from prose research

Default: Don't use subagents. Trust the research doc.

Handoff

After writing the plan document to memory-bank/plan/, hand off to plan-executor if the next step is the Execute phase.

Suggested next command:

/use plan-executor "memory-bank/plan/<file>.md"