c4-architecture-documentation - SKILL.md Agent Skill

name: c4-architecture-documentation description: Document system architecture using C4 model with context, container, component views and Mermaid diagrams license: Apache-2.0

C4 Architecture Documentation Skill

Purpose

Document MCP server architecture using C4 model for different abstraction levels with Mermaid diagrams.

When to Use

✅ Documenting system architecture (ARCHITECTURE.md)
✅ Security architecture documentation (SECURITY_ARCHITECTURE.md)
✅ Future architecture planning (FUTURE_ARCHITECTURE.md)
✅ Architecture decision records
✅ Onboarding new developers

Required Documentation Portfolio

Current State

Document	Purpose
ARCHITECTURE.md	Complete C4 models (Context, Container, Component)
DATA_MODEL.md	Data structures, entities, relationships
FLOWCHART.md	Business process and data flows
STATEDIAGRAM.md	System state transitions and lifecycles
MINDMAP.md	System conceptual relationships
SWOT.md	Strategic analysis and positioning
SECURITY_ARCHITECTURE.md	Current security design and controls

Future State

Document	Purpose
FUTURE_ARCHITECTURE.md	Architectural evolution roadmap
FUTURE_DATA_MODEL.md	Enhanced data architecture plans
FUTURE_FLOWCHART.md	Improved process workflows
FUTURE_STATEDIAGRAM.md	Advanced state management
FUTURE_MINDMAP.md	Capability expansion plans
FUTURE_SWOT.md	Future strategic opportunities
FUTURE_SECURITY_ARCHITECTURE.md	Planned security improvements

C4 Model Levels

Level 1: System Context

graph TB
    User[AI Assistant/Developer] -->|MCP Protocol| Server[European Parliament MCP Server]
    Server -->|REST API| EPAPI[European Parliament Open Data API]
    Server -->|JSON-LD| EPData[EP Data Portal]

Level 2: Container Diagram

graph TB
    Client[MCP Client] -->|stdio/SSE| MCPServer[MCP Server - Node.js/TypeScript]
    MCPServer -->|HTTP/JSON| EPClient[EP API Client]
    EPClient -->|REST| EPAPI[data.europarl.europa.eu]
    MCPServer -->|Zod| Schemas[Validation Schemas]

Level 3: Component Diagram

graph TB
    Tools[MCP Tools] --> Client[EP API Client]
    Resources[MCP Resources] --> Client
    Prompts[MCP Prompts] --> Client
    Client --> Cache[LRU Cache]
    Client --> RateLimiter[Rate Limiter]
    Client --> Validator[Zod Schemas]

Mermaid Diagram Standards

Use graph TB for top-bottom flow diagrams
Use sequenceDiagram for interaction flows
Use stateDiagram-v2 for state machines
Use mindmap for conceptual relationships
Include legends and descriptions

ISMS Policy References

Secure Development Policy - Architecture documentation requirements
Information Security Policy - Security architecture governance