# Backend Design: ECR-040 ScaleDefinition

| ID | BD-2026-040 |
| Status | Approved |
| Coding | Loop authorized |
| Level | L2 |
| Migration | NO |

## Backend Change Boundary

```text
Domain: ScaleDefinition (read projection of scales)
App: AdminHandler → admin.Service → ScaleRepo
API: GET /admin/explore/scales[+/:id]
Permission: admin.explore.read
UI: admin-h5 /catalogs
```

## Out of boundary

PATCH status · 题干编辑 · UGC · Payment

Rollback: remove routes/UI