Generate Architecture Documentation

Create comprehensive architecture documentation for a system or component.

Process

1. Parse Arguments

Extract from user input:

• Subject: System/component to document (required)
• Format: arc42, c4, or both (default: c4)
• Level: For C4 - context, container, or component (default: container)

2. Analyze System

Explore the codebase to understand:

1. System boundaries: What is in scope?
2. External dependencies: What systems does it interact with?
3. Internal structure: How is it organized?
4. Technology stack: What technologies are used?
5. Key flows: What are the important scenarios?

Use file exploration to gather information:

• Solution/project files for structure
• Configuration files for dependencies
• Entry points for architecture clues
• Existing documentation

3. Generate Documentation

Based on the format argument:

If format = c4:

1. Load the c4-documentation skill
2. Generate diagrams at the requested level:
   • context: System with users and external systems
   • container: Internal applications and data stores
   • component: Internal structure of a container
3. Include narrative description with each diagram

If format = arc42:

1. Load the arc42-documentation skill
2. Generate relevant sections:
   • Introduction and Goals
   • Architecture Constraints
   • System Scope and Context
   • Solution Strategy
   • Building Block View
   • Runtime View (key scenarios)
   • Deployment View
   • Cross-cutting Concepts

If format = both:

1. Generate arc42 document
2. Embed C4 diagrams in appropriate sections

4. Output Structure

Create documentation file(s):

For C4:
docs/architecture/
└── {subject}-c4-{level}.md

For arc42:
docs/architecture/
└── {subject}-arc42.md

For both:
docs/architecture/
├── {subject}-architecture.md  # arc42 with embedded C4
└── diagrams/
    ├── context.mmd
    ├── container.mmd
    └── component.mmd

5. Include in Output

Every generated document should include:

1. Header with metadata

   • Title
   • Last updated date
   • Author (if known)
   • Version

2. Diagrams (Mermaid format)

   • Properly formatted C4 diagrams
   • Legend if needed

3. Narrative

   • Context and purpose
   • Key decisions and rationale
   • Technology choices
   • Trade-offs acknowledged

4. References

   • Links to related docs
   • External resources
   • ADRs if applicable

Example Invocations

/doc-architecture "order service"
→ Generates C4 container diagram for order service

/doc-architecture "payment gateway" format=arc42
→ Generates full arc42 documentation

/doc-architecture "api gateway" format=c4 level=component
→ Generates C4 component diagram

/doc-architecture "entire system" format=both level=context
→ Generates arc42 with embedded C4 context diagram

Quality Criteria

Generated documentation must:

• Accurately reflect the system structure
• Use consistent terminology
• Include valid Mermaid/PlantUML syntax
• Explain the "why" not just the "what"
• Be actionable for readers
• Follow project documentation conventions