Writing plans

<EXTREMELY-IMPORTANT> After the design outline is approved, you MUST use this skill to create the implementation plan. Every function task MUST be broken into RED→GREEN→REFACTOR Triplet. "Write code first, add tests later" is forbidden. The plan MUST reference implementing (per-function implementation + review + testing) and closing-the-loop at the end. </EXTREMELY-IMPORTANT>

Writing Plans: Function Breakdown + Anti-Duplication + Reuse Annotation

Skill Type: Flexible

The granularity and grouping of task breakdown may adapt to context, but the TDD Triplet structure, Anti-Duplication checks, and execution chain completeness are mandatory.

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Execution Chain

brainstorming(design outline) → writing-plans(break into TDD Triplets) → implementing(per function) → closing-the-loop

implementing carries the three phases of implementation, review, and testing. writing-plans is responsible for task breakdown + reuse annotation, not for defining how to review and test — that is implementing's responsibility.

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Step 1: Function Breakdown — TDD Triplet

Granularity Standard

Too Coarse	Just Right
"Implement user authentication module"	Break into: login, register, token refresh — each goes through TDD Triplet
"Refactor database layer"	Break into: change connection config, change query methods, change transaction boundaries — each goes through TDD

One function = one independently verifiable, user-visible behavior. After breakdown, each function goes through one complete implementing cycle (TDD → review → testing).

Project Type Adaptation

Project Type	Function Breakdown Unit	"Test Passes" Meaning
Backend	API endpoint / Service method	Correct response + boundary coverage
Frontend	Component / Page / Route	Correct rendering + correct interaction behavior
Full-stack	Frontend function + Backend endpoint (paired)	Frontend→Backend→Response full chain
Plugin	Skill / Hook / Config	Complete content + correct format

TDD Triplet Template (Mandatory)

Task Group X: {function description}

X-R  RED: Write test first
     ├─ File: test file path
     ├─ Content: Write tests based on brainstorming's 2-layer × 4-category scenarios
     ├─ Verify: Tests → FAIL (Red)
     └─ Commit: git commit -m "RED: {scenario description}"

X-G  GREEN: Minimal implementation
     ├─ File: implementation file path
     ├─ Content: Write only the code that makes X-R tests pass, YAGNI
     ├─ L4 Signature Verification: Read at least 3 key method signatures being called
     ├─ Verify: Tests → PASS (Green)
     ├─ Depends on: X-R
     └─ Commit: git commit -m "GREEN: {implementation description}"

X-F  REFACTOR: Clean up
     ├─ File: same as X-G
     ├─ Content: Eliminate duplication, improve naming, extract constants, keep tests green
     ├─ Verify: Tests → PASS
     ├─ Depends on: X-G
     └─ Commit: git commit -m "REFACTOR: {cleanup description}"

Dependency Direction

❌ Wrong: D3 (implement Service) → T1 (test Service)    ← Waterfall
✅ Right: T1-R → T1-G → T1-F (GREEN depends on RED)

Pure Data Structure Exemption

Entity/Enum/DTO containing only field declarations/getters/setters/annotations, with zero if/for/throw/return → may skip TDD, annotate "No TDD (pure data structure)." Any branch or loop → must use Triplet.

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Step 2: Anti-Duplication (Mandatory Checklist)

Execute item by item before planning each new class/method.

#	Check Item	Action
1	Check roadmap §4 first	Read knowledge-base/{project-name}/{project-name}-roadmap.md §4 (existing encapsulated method index), confirm no similar encapsulation
2	New Service method?	Grep method name **/service/**/*.java
3	New DTO/VO?	Glob **/dto/**, **/vo/**
4	New util method?	Grep method signature **/utils/**, **/common/**
5	New Mapper method?	Grep method name **/mapper/**
6	New constant/enum?	Grep constant name **/enums/**
7	New dependency?	Grep artifactId pom.xml
8	Functionally similar method?	Grep business keyword **/*.java (fuzzy search)

Judgment criteria: Existing method name differs by ≤2 words AND parameter list is essentially the same → reuse. Existing DTO covers ≥80% of fields → extend fields.

roadmap §4 takes priority over code search. The roadmap already indexes the project's encapsulated methods — check roadmap first to avoid missing anything.

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Step 3: L2/L3 Reuse Annotation

From brainstorming's L4 exploration results, annotate reusable components for each task:

Task Group T1: CouponTemplateService
  T1-R → Reuse: Existing Service test pattern (reference XxxServiceTest)
  T1-G → Reuse: BaseEntity's createTime/updateTime

L2 Search: Search knowledge-base/通用编码经验.md for optimal solutions in the current problem domain. Subagent search is recommended (L2 file may be tens of thousands of lines — saves main context).

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Plan Output Format

## Implementation Plan: {feature name}

> Linked Design Outline: {roadmap phase} | Project Type: {backend/frontend/full-stack/plugin}

### Reusable Component Summary
| Existing Component | Path | Source | Used In |
|-------------------|------|--------|---------|
| xxx | xxx.java | roadmap §4 | T1-G |

### Function-Level Task Groups

#### Task Group X: {function description}
| # | Sub-Task | File | Key Points | Verification | Depends On |
|---|----------|------|-----------|-------------|------------|
| X-R | RED: {test description} | Test file | 2-layer × 4-category scenarios | Tests → FAIL | — |
| X-G | GREEN: {implementation description} | Impl file | Minimal impl + L4 verify ≥3 signatures | Tests → PASS | X-R |
| X-F | REFACTOR: {cleanup description} | Same as X-G | DRY + naming + constants | Tests → PASS | X-G |

#### Pure Data Structure Tasks
| # | Task | File | Verification | Depends On |
|---|------|------|-------------|------------|
| B1 | Create XxxEnum | enums/XxxEnum.java | Compiles | — |

### Execution Order

Each task group independently goes through implementing (TDD → review → sub-function full testing).
After all task groups pass, execute full-scenario integration testing.
Finally execute closing-the-loop.

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Red Flags — Your Plan Has Structural Problems

Your Thought	Reality
"List all implementations first, put testing as the last phase"	This is Waterfall. TDD requires RED before every function.
"Writing a new one is faster, searching for existing ones is too slow"	Writing new: 5 min + debugging: 20 min. Check roadmap §4 first, then Grep — total 2 min.
"Tests depend on implementation, so implementation must be done first"	Dependency direction is reversed. RED is written first, GREEN depends on RED.
"This function is too special, there's definitely nothing existing"	Check roadmap §4 first — it exists precisely to answer "is there something existing?"
"The plan is just a task list, execution chain is something for execution time"	Plan structure determines execution structure. Tests at the end → execution becomes "write code then backfill tests."

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Completion Criteria

Must confirm before entering implementing:

• All functions broken into RED → GREEN → REFACTOR Triplets (pure data structures excepted)
• Each Triplet has correct dependency direction (GREEN depends on RED)
• Anti-Duplication checks executed (roadmap §4 + Grep, 8 items total)
• Each task annotated with reusable existing components
• L2 search completed (subagent recommended), relevant patterns annotated
• No standalone "testing phase" — testing is interleaved within function Triplets
• User has confirmed the task list