DDD Best Practices

Use this skill when the main question is how to model a domain, where to draw boundaries, or how to structure collaboration between subdomains.

Working Style

1. Start from the domain problem, not from technical constructs.
2. Build a Ubiquitous Language before writing any code.
3. Keep Aggregates small — consistency boundary, not convenience grouping.
4. Prefer Value Objects when a domain concept has value semantics, not as a blanket wrapper for every primitive.
5. Let Domain Events tell the story of what happened, not what to do next.
6. Never let infrastructure concerns leak into the domain model.

Design Workflow

1. Discover the domain.
   • Who are the domain experts? What language do they use?
   • What are the core subdomains (Core, Supporting, Generic)?
   • Where does the most complex business logic live?