Agent-Skills.md

Agent Skills: NestJS Architecture Expert

Design decoupled, testable NestJS module boundaries with feature, core, and shared modules. Use when structuring module imports, creating feature modules, or enforcing separation of concerns in NestJS. (triggers: **/*.module.ts, main.ts, NestFactory, Module, Controller, Injectable)

UncategorizedID: hoangnguyen0403/agent-skills-standard/nestjs-architecture

Repository

hoangnguyen0403/agent-skills-standard
HoangNguyen0403License: Apache-2.0
362103

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pnpm dlx add-skill https://github.com/HoangNguyen0403/agent-skills-standard/tree/HEAD/skills/nestjs/nestjs-architecture

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skills/nestjs/nestjs-architecture/SKILL.md

Skill Metadata

Name
nestjs-architecture
Description
Design NestJS module boundaries, provider scope, and request pipeline choices. Use when structuring modules, placing guards/pipes/interceptors, or reviewing provider lifetime in NestJS.

NestJS Architecture Expert

Priority: P0 (CRITICAL)

Design feature modules with singleton-first providers and explicit request-pipeline choices.

Decision Map

  • Module role: Feature Modules (Auth) vs Core (Config/DB) vs Shared (Utils). Feature owns its controllers, application services, and adapters. Shared exports stateless helpers only.
  • Provider scope: default singleton. Use request scope only for tenant context, request-local caching, or request tracking. Treat request scope as a measured exception.
  • Pipeline choice: middleware for raw HTTP concerns, guard for access decisions, pipe for validation/transforms, interceptor for cross-cutting request/response behavior, filter for error translation.

Recipe

  1. Create bounded feature: module + controller + application service + persistence adapter.
  2. Keep controller thin: Thin controllers, fat services. No business in Controller. Move logic to Service.
  3. Register dependencies once: imports for modules, providers for services, exports only for true consumers. @InjectRepository() dependencies need TypeOrmModule.forFeature([...]).
  4. Validate at edges: DTO validation pipes for incoming data; never trust raw payloads in services.
  5. Check circular imports: check circular dependencies with madge; refactor contracts first and use forwardRef() only as last resort.

Verify

  • [ ] Feature module owns one business capability, not a mixed grab bag.
  • [ ] Providers are singleton unless request scope has a written reason.
  • [ ] Guard/pipe/interceptor/filter placement matches the request lifecycle.
  • [ ] Config uses @nestjs/config or a typed config layer, not scattered process.env.
  • [ ] Dependency Integrity: DB repositories, queues, and clients are registered in the module graph, not manually instantiated.

Anti-Patterns

  • No request scope by default: Singleton first; justify heavier scope.
  • No business logic in controllers: Delegate orchestration to services/use cases.
  • No entity leakage: Don't return ORM entities; return DTOs or response models.
  • No manual instantiation: Use DI; never new Service() inside Nest code.

References