M09 Domain

The m09-domain skill guides developers in applying Domain-Driven Design (DDD) principles to Rust code by helping them classify domain concepts as entities, value objects, aggregates, or repositories before implementation. It's designed for Rust developers building complex business domains who need to understand how to translate domain concepts into appropriate Rust ownership patterns and type structures. The skill solves the problem of misaligning code architecture with business logic by providing a decision framework that traces domain modeling choices upward to business constraints and downward to concrete Rust implementation patterns.

skills.sh installs: 750
GitHub stars: 1.3K
last updated: Jul 14, 2026

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Install

$ npx -y skills add zhanghandong/rust-skills --skill m09-domain --agent claude-code

Installs into .claude/skills of the current project.

Files

Domain Modeling

Layer 2: Design Choices

Core Question

What is this concept's role in the domain?

Before modeling in code, understand:

Is it an Entity (identity matters) or Value Object (interchangeable)?
What invariants must be maintained?
Where are the aggregate boundaries?

Domain Concept → Rust Pattern

Domain Concept	Rust Pattern	Ownership Implication
Entity	struct + Id	Owned, unique identity
Value Object	struct + Clone/Copy	Shareable, immutable
Aggregate Root	struct owns children	Clear ownership tree
Repository	trait	Abstracts persistence
Domain Event	enum	Captures state changes
Service	impl block / free fn	Stateless operations

Thinking Prompt

Before creating a domain type:

What's the concept's identity?
- Needs unique identity → Entity (Id field)
- Interchangeable by value → Value Object (Clone/Copy)
What invariants must hold?
- Always valid → private fields + validated constructor
- Transition rules → type state pattern