Domain-Driven Design

Use this skill when

• You need to model a complex business domain with explicit boundaries.
• You want to decide whether full DDD is worth the added complexity.
• You need to connect strategic design decisions to implementation patterns.
• You are planning CQRS, event sourcing, sagas, or projections from domain needs.

Do not use this skill when

• The problem is simple CRUD with low business complexity.
• You only need localized bug fixes.
• There is no access to domain knowledge and no proxy product expert.

Instructions

• Run a viability check before committing to full DDD.
• Produce strategic artifacts first: subdomains, bounded contexts, language glossary.
• Route to specialized skills based on current task.
• Define success criteria and evidence for each stage.

Viability check

Use full DDD only when at least two of these are true:

• Business rules are complex or fast-changing.
• Multiple teams are causing model collisions.
• Integration contracts are unstable.
• Auditability and explicit invariants are critical.

Routing map

• Strategic model and boundaries: @ddd-strategic-design
• Cross-context integrations and translation: @ddd-context-mapping
• Tactical code modeling: @ddd-tactical-patterns
• Read/write separation: @cqrs-implementation
• Event history as source of truth: @event-sourcing-architect and @event-store-design
• Long-running workflows: @saga-orchestration
• Read models: @projection-patterns
• Decision log: @architecture-decision-records

If templates are needed, open references/ddd-deliverables.md.

Output requirements

Always return:

• Scope and assumptions
• Current stage (strategic, tactical, or evented)
• Explicit artifacts produced
• Open risks and next step recommendation

Examples

Use @domain-driven-design to assess if this billing platform should adopt full DDD.
Then route to the right next skill and list artifacts we must produce this week.

Limitations

• This skill does not replace direct workshops with domain experts.
• It does not provide framework-specific code generation.
• It should not be used as a justification to over-engineer simple systems.