sdd-mcp: Skill for Claude Code

SDD Technical Design Generation

Generate comprehensive technical design documents that translate approved requirements into actionable architecture specifications.

Prerequisites

Before generating design:

1. Requirements must be generated using /sdd-requirements
2. Requirements phase should be approved (use sdd-approve requirements MCP tool)
3. Review existing architecture in .spec/steering/tech.md and .spec/steering/structure.md

Workflow

Step 1: Verify Prerequisites

Use sdd-status MCP tool to verify:

• requirements.generated: true
• requirements.approved: true (recommended before design)

Step 2: Review Requirements

1. Read .spec/specs/{feature}/requirements.md
2. Identify all functional requirements (FR-*)
3. Identify all non-functional requirements (NFR-*)
4. Note constraints and assumptions

Step 3: Choose Architecture Pattern

Select appropriate patterns based on requirements:

Pattern	Use When	Key Characteristics
Clean Architecture	Domain-heavy apps	Layers: Domain → Use Cases → Interface → Infrastructure
MVC/MVP	Web applications	Model-View-Controller separation
Microservices	Distributed systems	Independent deployable services
Event-Driven	Async processing	Event producers and consumers
Hexagonal	Testable business logic	Ports and Adapters pattern

Step 4: Design Components

For each component, specify:

## Component: {ComponentName}

**Type:** Service | Controller | Repository | Adapter | Provider

**Purpose:** {Single responsibility description}

**Responsibilities:**
- {Responsibility 1}
- {Responsibility 2}

**Interface:**
```typescript
interface I{ComponentName} {
  methodName(input: InputType): Promise<OutputType>;
}

Dependencies:

• {Dependency 1 via interface}
• {Dependency 2 via interface}

Error Handling:

• {Error scenario 1}: {How to handle}

### Step 5: Define Data Models