| name | new-spec-usecase |
| description | Create the usecase layer spec template at `docs/spec/<feature>/usecase.md`. Asks for feature name (kebab-case) + usecase package name (lowercase, e.g., `user`) + Usecase interface name (default `Usecase`) via `AskUserQuestion`, reads the section structure for the usecase layer from `.claude/scaffold-spec/usecase-spec.md`, then writes a Markdown file with YAML code-block placeholders and TODO markers (Overview / Interface / DTOs / Dependencies / Workflow). NEVER overwrites an existing file. Does not invent business content — gathers identity only. Reads the spec format file at runtime so format changes propagate automatically. |
New Spec — Usecase
Create the usecase layer spec template for one feature.
A Japanese reference translation of this skill is available at SKILL.ja.md in the same directory (not loaded as a skill; for human reference only).
When to Use
- Starting a new feature and need the usecase layer spec template.
- Adding the usecase spec to an existing feature directory.
Do NOT use this skill for:
- Editing an existing
usecase.md — open in the editor directly.
- Generating Go code from spec — that's
scaffold-usecase.
- Validating spec consistency — that's
verify-spec.
- Creating both layer specs (domain + usecase) in one go — use the integrator
new-spec. lean A only requires these two specs; controller / infra are derived from OpenAPI gen + sqlc gen, no spec file.
What This Skill Reads / Writes
Reads (always):
.claude/scaffold-spec/usecase-spec.md — canonical section list for the usecase layer.docs/spec/<feature>/ — checks whether usecase.md already exists.
Writes (with confirmation):
docs/spec/<feature>/usecase.md — template file.
Never touches:
- Existing
usecase.md (aborts if found).
- Any other layer's spec file.
First Step: Confirm Identity
This skill MUST call AskUserQuestion immediately after invocation (unless invoked from new-spec integrator with the feature name in context):
- Feature name — free-text, kebab-case. Validate
^[a-z][a-z0-9-]*$.
- Usecase package name — free-text, lowercase (e.g.,
user, order).
- Usecase interface name — free-text, default
Usecase (PascalCase).
If docs/spec/<feature>/usecase.md exists → abort. Otherwise create docs/spec/<feature>/ if missing.
Step 1. Read Section Definitions
Read .claude/scaffold-spec/usecase-spec.md for the canonical section list:
- Overview
- Interface
- DTOs
- Dependencies
- Workflow
NEVER hardcode — re-read the spec format file each run.
Step 2. Generate the Template
Assemble Markdown with H1 title <FeatureName Display> — Usecase Spec, then per section:
- Overview: single
TODO: line
- Interface: YAML code block with
package / name / methods (1 placeholder method)
- DTOs: YAML code block with placeholder DTO struct
- Dependencies: YAML code block with placeholder boundary list
- Workflow: H3 per method with YAML block (
tx_required / steps / calls / errors)
Use the example output shown in .claude/scaffold-spec/usecase-spec.md as the literal template format.
Step 3. Confirm and Write
Display proposed path + first ~20 lines, then ask:
- 「以下の内容で
docs/spec/<feature>/usecase.md を作成しますか？」
- Options: 「作成する」 / 「キャンセル」
If approved, mkdir -p docs/spec/<feature> and Write the file.
Step 4. Closing
docs/spec/<feature>/usecase.md を作成しました。次は editor で TODO を埋めてください。
domain spec も必要なら new-spec-domain または統合 new-spec を使ってください
（lean A 構成: controller / infra spec は不要、OpenAPI gen + sqlc gen から導出されます）。
AI Modification Scope
- Write scope: new files under
docs/spec/<feature>/ only.
- Aborts if
usecase.md exists.
Constraints
- ❌ Overwrite an existing
usecase.md
- ❌ Invent business content (methods / DTOs / workflow)
- ❌ Hardcode section list (always read
.claude/scaffold-spec/usecase-spec.md)
- ❌ Skip the identity
AskUserQuestion
- ❌ Touch any layer other than
usecase.md
- ✅ Japanese user-facing output
- ✅ Validate feature name kebab-case + package name lowercase
Checklist
