Backend Coding Standards

Quick Decision

• Entity or value object? → backend-domain
• Command/Query handler? → backend-application
• Prisma repository or mapper? → backend-infra
• Controller? → backend-presentation
• Exception or test? → backend-errors-and-tests
• Module/naming/checklist? → backend-conventions
• Overview/structure? → backend-overview

Creation Order (CRUD Feature)

1. Entity → backend-domain
2. Repository interface → backend-domain
3. Mapper → backend-infra
4. PrismaRepository → backend-infra
5. Command + Handler → backend-application
6. Controller → backend-presentation
7. Tests → backend-errors-and-tests

General Rules (All Backend)

• Controllers: NEVER put logic in controllers — only receive, build command/query (simple mapping), dispatch, return; create Command/Query + Handler for any logic
• Commands: Never pass RepositoryTransaction between commands — each command manages its own transaction via repositoryTransactionService.execute()
• Language: English for all code, comments, docs
• Never modify: **/prisma-generated-types/
• Prisma enums: Every enum must have a ValueObject + re-export as XxxEnum; never import from prisma-generated-types in domain/application/presentation — see backend-conventions
• Package manager: Yarn (never npm/pnpm)
• Framework: NestJS 11, DDD, CQRS, Prisma, Swagger, Jest

Shared Configuration

• ESLint: backend/eslint.config.mjs
• Prettier: backend/.prettierrc
• Build: From backend/ root: yarn build

Deploy Workflows

• Template: .github/workflows/deploy-backend-template.yml
• Workflows: deploy-api.yml
• Docker: infra/dockerfiles/backend/RuntimeWithPrisma.Dockerfile (context: ./backend)

References

• Frontend: .agents/skills/frontend/SKILL.md
• Project overview: AGENTS.md