| name | feature-completeness |
| description | Traces a feature end-to-end (UI, hook, service, API, controller, database) to verify every link is wired. Use after completing a multi-layer feature or when asked whether a feature is fully connected. |
Feature Completeness Skill
Purpose
Verify that a newly created feature is fully wired end-to-end — from UI component through hooks/services to API endpoint to backend controller/service/database. Catches disconnected pieces that compile but don't actually work together.
Activation
- After completing a multi-layer feature (FE + BE)
- After creating a new page/container that calls an API
- When user reports "it builds but doesn't work"
How It Works
This skill traces the full request path from UI to database and back, verifying each connection point. It's technology-agnostic — it detects the layers from the architecture-scanner cache.
Phase 1: Identify the Feature Chain
For a full-stack feature, the chain is:
Generic chain (adapts to any stack):
UI Layer → User sees/clicks something
↓
State/Hook Layer → Manages data fetching/mutation
↓
Service Layer → Makes HTTP call to API
↓
API Layer → Receives request, routes to handler
↓
Business Layer → Processes logic, validates, transforms
↓
Data Layer → Reads/writes database
↓
Database → Table exists with correct schema
Stack-specific chains:
React + .NET:
Component → useQuery/useMutation → service.ts → API URL →
Controller.cs → Service.cs → Repository → DbContext → SQL Table
React + Express:
Component → useQuery/useMutation → service.ts → API URL →
router.ts → controller.ts → service.ts → Prisma/Sequelize → SQL Table
React + FastAPI:
Component → useQuery/useMutation → service.ts → API URL →
router.py → service.py → SQLAlchemy → SQL Table
Vue + Django:
Component → composable → api.ts → API URL →
views.py → serializer.py → model.py → SQL Table
Phase 2: Trace Each Link
For each link in the chain, verify it exists and connects correctly:
Link 1: UI → Hook/State
Check: Does the component import and call the hook?
Grep component file for hook name (e.g., useGetOrders)
Verify: hook is called, return value is used (data, isLoading, error)
Fail if: hook is imported but never called, or return values are ignored
Link 2: Hook → Service
Check: Does the hook call the service function?
Read hook file → find queryFn or mutationFn
Verify: service function is imported and called with correct params
Fail if: service function doesn't exist or signature doesn't match
Link 3: Service → API URL
Check: Does the service make an HTTP call to the correct URL?
Read service file → find axios/fetch call
Verify: URL matches a known backend route (check architecture-scanner cache)
Fail if: URL has no matching backend route (a recurring bug class — see the
lessons-learned skill's log for project-specific instances)
Link 4: API URL → Controller
Check: Does the backend controller have a matching route?
Grep controllers for the URL path
Verify: HTTP method matches (GET/POST/PUT/DELETE)
Fail if: no controller route matches
Link 5: Controller → Service
Check: Does the controller call the service method?
Read controller method → find service call
Verify: service interface is injected and method exists
Fail if: service method doesn't exist or parameters don't match
Link 6: Service → Repository/DB
Check: Does the service access the database?
Read service method → find repository/DB calls
Verify: entity type is correct, query filters are present
Fail if: repository for this entity isn't registered (a recurring bug class —
see the lessons-learned skill's log for project-specific instances)
Link 7: Database → Table
Check: Does the database table exist?
Check DbContext for DbSet declaration
Check for database change script in .codex/idev/database-changes/
Warn if: DbSet exists but no table creation script found
Phase 3: Report Results
Feature Completeness: Orders CRUD
Chain: UI → Hook → Service → API → Controller → Service → DB
✓ Link 1: OrdersTabContainer → useGetOrders (called, data used)
✓ Link 2: useGetOrders → ordersService.getAll (imported, called)
✓ Link 3: getAll → GET api/orders/get-all (URL found in architecture cache)
✓ Link 4: api/orders/get-all → OrdersController.GetAll (route match)
✓ Link 5: GetAll → _orderService.GetAll (injected, method exists)
✓ Link 6: GetAll → _repository.GetAllAsync (IGenericRepository<Order> registered)
⚠ Link 7: DbSet<Order> exists, DB table pending DBA execution
Result: Feature is wired end-to-end. Blocked on: database table creation.
Phase 4: Common Disconnection Points
Issues this skill catches that compile but fail at runtime:
1. Component renders but shows no data
→ Hook is called but service function returns wrong URL (404)
2. Service call succeeds but data shape is wrong
→ FE type doesn't match BE DTO fields (api-contract-validation catches this)
3. Controller receives request but service throws
→ Service depends on unregistered repository (post-creation-verify catches this)
4. Everything works but wrong data appears
→ Query filter missing the tenant filter column (multi-tenancy leak; e.g., a ClientId column)
→ Query missing the soft-delete flag check (e.g., a RecordStatusId column)
5. Feature works for create but not update/delete
→ Only some CRUD operations were wired
→ Missing mutation hooks or service functions
6. Page loads but route doesn't work
→ Component created but route not registered in the project's route registration file (e.g., Routes.tsx)
Phase 5: Completeness Checklist
Auto-generated based on detected stack:
Full-Stack CRUD Feature
□ FE Types: Request/Response interfaces defined
□ FE Service: All CRUD functions (getAll, getById, create, update, delete)
□ FE Hooks: useQuery for reads, useMutation for writes
□ FE Container: Imports hooks, handles loading/error/empty states
□ FE Route: Page registered in router (if new page)
□ BE Entity: Created with all required fields
□ BE DTOs: Return, Create, Update DTOs + mapping extensions
□ BE Interface: Service interface with all methods
□ BE Service: Implementation with error handling
□ BE Controller: All route handlers
□ BE DI: Service + Repository registered
□ BE DbContext: DbSet declared
□ DB: Table creation script exists
□ Contract: FE types match BE DTOs
□ Chain: All 7 links verified connected
Phase 6: Integration
Complete feature creation workflow:
1. lessons-learned → prevention steps
2. Create BE files (entity, DTOs, service, controller)
3. post-creation-verify → registrations
4. build-check → BE compiles
5. Create FE files (types, service, hooks, container)
6. build-check → FE compiles
7. api-contract-validation → FE↔BE types match
8. feature-completeness → end-to-end chain verified ← THIS SKILL
9. self-review → code quality
10. Report to user
Anti-Patterns
- Do NOT run for single-file changes — only for multi-layer features
- Do NOT trace into external libraries — stop at the project boundary
- Do NOT check every CRUD operation individually — check the pattern once
- Do NOT block on database table not existing — warn and continue
- Do NOT re-read files already checked by other skills — use cached results
