PlantUML Skill

📖 Overview

plantuml-skill is a professional "Diagrams as Code" tool for AI agents and developers. It allows you to write, render, and export high-fidelity PlantUML diagrams with a curated, modern aesthetic.

Unlike basic diagram tools, this skill is optimized for Software Architecture (C4 Model), complex system flows, and state machines, ensuring your documentation looks premium and technically accurate.

🚀 When to use this skill

• System Design: Visualizing microservices, database schemas, and infrastructure.
• Process Mapping: Documenting complex business logic, user journeys, or API authentication flows.
• Architecture Reviews: Creating C4 diagrams for technical design documents.
• Legacy Documentation: Turning source code or logs into readable sequence diagrams.
• Education: Generating clean visual aids for complex algorithms or lifecycles.

🛠 Prerequisites

The skill features a self-healing setup script, but generally requires:

1. Java (JRE 8+): Required to run the PlantUML engine.
2. Graphviz (dot): Required for all structural diagrams (Class, Use Case, etc.).
3. Python 3.x: To run the render.py automation wrapper.

Note: The skill will attempt to install these automatically via winget, brew, or apt if they are missing.

📥 Installation

npx skills add https://github.com/jovd83/plantuml-skill --skill plantuml-skill

🎨 Visual UML Gallery

1. Sequence Diagram

Best for: API flows, user interactions, and message passing.

2. Use Case Diagram

Best for: Mapping system boundaries and actor responsibilities.

3. Class Diagram (Domain Model)

Best for: Structural data modeling and object relationships.

4. Activity Diagram

Best for: Business processes and complex logic flows with swimlanes.

5. C4 Container Diagram

Best for: High-level software architecture and container boundaries.

6. State Machine

Best for: Object lifecycles and application state management.

7. Deployment Diagram

Best for: Physical infrastructure and network topology.

8. Component Diagram

Best for: Microservices architecture and internal system modules.

9. Object Diagram

Best for: Dynamic snapshots of system states at a specific point in time.

10. Timing Diagram

Best for: Real-time signal processing and hardware timing.

📚 Documentation & Resources

For detailed guides, please refer to:

• Syntax Guide: High-fidelity UML and C4 syntax patterns.
• Troubleshooting Guide: Common fixes for Java and Graphviz environments.