AgentSkillsCN

domain-driven-design

适用于建模领域概念、聚合对象与限界上下文，或用于检查现有代码中是否符合领域驱动设计（DDD）的原则。

SKILL.md
--- frontmatter
name: domain-driven-design
description: Use when modeling domain concepts, aggregates, and bounded contexts or checking DDD alignment in existing code.

Domain-Driven Design (DDD) Professional Standard

This skill is based on the Domain-Driven Design Crew and industry-standard architectural patterns. Use this to ensure the codebase remains a faithful representation of the business domain.

1. Strategic Design (The Big Picture)

Bounded Contexts

  • •Define clear logical boundaries where a specific model applies.
  • •Rule: One context, one language, one team.
  • •Pattern: Communicate across contexts via Application Services or Domain Events. Use an Anti-Corruption Layer (ACL) when integrating with legacy or external systems.

Ubiquitous Language

  • •Use the exact terminology of domain experts in the code.
  • •Rule: If a domain expert calls it a ResearchBlueprint, don't call it ProjectDraft.

2. Tactical Design (The Building Blocks)

Aggregates

  • •A cluster of domain objects that can be treated as a single unit.
  • •Aggregate Root: The only entry point for modifications (e.g., Order is the root for OrderItem).
  • •Rule: Transactions should only modify one aggregate at a time. Refer to other aggregates by ID only.

Entities vs. Value Objects

  • •Entity: Has a unique identifier (id). Its identity persists even if attributes change (e.g., User).
  • •Value Object: No identity. Defined only by its attributes. Immutable. (e.g., Money, Address).
  • •Rule: Prefer Value Objects for descriptors to reduce complexity.

Domain Services

  • •Logic that doesn't belong to a single entity (e.g., InnovationDebateService).
  • •Rule: Keep them stateless and purely focused on domain logic.

3. Layered Architecture (Isolation)

Interface Layer (interfaces/)

  • •Handles HTTP/CLI input. Validates request shapes.
  • •Constraint: No business logic. Call only the Application Layer.

Application Layer (application/)

  • •Orchestrates use cases. Loads aggregates via repositories.
  • •Constraint: No business logic. No database specifics.

Domain Layer (domain/)

  • •Pure business logic. Entities, Value Objects, and Domain Service interfaces.
  • •Constraint: Zero dependencies on technical frameworks (FastAPI, SQLAlchemy).

Infrastructure Layer (infrastructure/)

  • •Technical implementations (Repositories, AI Agents, DB Sessions).
  • •Constraint: Implements interfaces defined by the Domain/Application layers.

4. Operational Workflow

  1. •Clarify: Before coding, identify the Bounded Context.
  2. •Model: Define Entities and Value Objects in the Domain layer first.
  3. •Encapsulate: Protect invariants within Aggregates.
  4. •Abstract: Define Repository interfaces in the Domain; implement them in Infrastructure.
  5. •Orchestrate: Create an Application Service (Use Case) to wire them together.