Task Decomposition

Translates an implementation-ready change into a queue of bite-sized tasks.

The canonical prompt (verbatim from v1 SOP)

将所有任务进行拆分，其中前端与后端任务要分开，每个任务不超过 2 个文件的改动，每个任务单独任务文档，任务按照优先级排序，任务文档名称和文件夹名称尽可能用中文。

Why these constraints

Constraint	Why
≤ 2 files	Forces tight blast radius; Agent stays focused; reviews are easy.
One doc per task	Audit / trace / parallel review without merge conflicts.
Chinese names	Project policy; improves PM legibility.
FE/BE separation	Different reviewers; different risk profiles; cleaner deploys.
Priority order	First task to clear must unlock the most downstream value.

Output structure

openspec/changes/<slug>/
├── tasks.md                    # index, ordered list with links + status checkboxes
└── tasks/
    ├── 后端-01-用户匹配引擎雏形.md
    ├── 后端-02-匹配规则配置层.md
    ├── 前端-01-匹配结果展示页.md
    └── ...

Each task document:

# 后端-01 · 用户匹配引擎雏形

- **状态**: [ ] 未开始 / [x] 已完成
- **优先级**: P0
- **依赖**: -
- **预计文件**:
  - backend/match/engine.py (new)
  - backend/match/__init__.py (edit)
- **Spec 引用**: S1-match-engine
- **验收**: <criteria>
- **风险**: <if any>

Workflow

1. Walk specs/* — derive 1-N tasks per spec.
2. Classify each task as Frontend / Backend / Both (Both is rare; usually splits into two tasks).
3. Estimate files touched — if > 2, split further.
4. Order by P0 → P3.
5. Write per-task documents.
6. Write tasks.md index linking to each.

Common failure modes

1. Mega-task with 5 files — "refactor + add" combo. Mitigation: hard limit, refuse to write a task with > 2 files.
2. No priority — "all P0". Mitigation: enforce at most 30% P0 of total.
3. Cross-track dependency — frontend task waits on backend task, no annotation. Mitigation: dependencies field is required.
4. English-only naming — "task-001-match-engine". Mitigation: project policy is Chinese; apply unless team agrees otherwise.