C4 Architecture Documentation

Generate architecture documentation using C4 model Mermaid diagrams. Use when asked to create architecture diagrams, document system architecture, visualize software structure, create C4 diagrams, or generate context/container/component/deployment diagrams. Triggers include "architecture diagram", "C4 diagram", "system context", "container diagram", "component diagram", "deployment diagram", "document architecture", "visualize architecture".

Workflow

1. Understand scope, Determine which C4 level(s) are needed based on audience
2. Analyze codebase, Explore the system to identify components, containers, and relationships
3. Generate diagrams, Create Mermaid C4 diagrams at appropriate abstraction levels
4. Document, Write diagrams to markdown files with explanatory context

C4 Diagram Levels

Select the appropriate level based on the documentation need:

Level	Diagram Type	Audience	Shows	When to Create
1	C4Context	Everyone	System + external actors	Always (required)
2	C4Container	Technical	Apps, databases, services	Always (required)
3	C4Component	Developers	Internal components	Only if adds value
4	C4Deployment	DevOps	Infrastructure nodes	For production systems
-	C4Dynamic	Technical	Request flows (numbered)	For complex workflows

Key Insight: "Context + Container diagrams are sufficient for most software development teams." Only create Component/Code diagrams when they genuinely add value.

Quick Start Examples

System Context (Level 1)

C4Context
  title System Context - Workout Tracker

  Person(user, "User", "Tracks workouts and exercises")
  System(app, "Workout Tracker", "Vue PWA for tracking strength and CrossFit workouts")
  System_Ext(browser, "Web Browser", "Stores data in IndexedDB")