UML Generation Skill

Version: v0.17.1

Purpose

Analyze source code and generate UML diagrams with PlantUML syntax and online rendering URLs.

When to Invoke

• Code analysis requiring visual documentation
• Architecture review and documentation
• Reverse-engineering existing codebases
• Understanding class hierarchies
• Documenting API call flows
• Technical debt visualization (with anti-pattern-analysis)

Supported Diagrams

Output Format

Each diagram includes:

1. PlantUML Source - Copyable syntax
2. Online URL - http://www.plantuml.com/plantuml/svg/[encoded]
3. Download Links - SVG and PNG variants

PlantUML Quick Reference

Class Diagram

@startuml
class ClassName {
  +publicField: Type
  -privateField: Type
  +publicMethod(): ReturnType
}
ClassA <|-- ClassB        ' inheritance
ClassA <|.. ClassB        ' implementation
ClassA *-- ClassB         ' composition
ClassA --> ClassB         ' association
ClassA "1" --> "*" ClassB ' multiplicity
@enduml

Sequence Diagram

@startuml
participant Client
participant Server
Client -> Server: request()
activate Server
Server --> Client: response
deactivate Server
alt success
  Server --> Client: 200 OK
else error
  Server --> Client: 500 Error
end
@enduml

Component Diagram

@startuml
package "Frontend" {
  [Web App]
}
package "Backend" {
  [API Gateway]
  [User Service]
}
[Web App] --> [API Gateway]
[API Gateway] --> [User Service]
@enduml

URL Encoding

1. UTF-8 encode source
2. Deflate compress
3. Base64-like encode (PlantUML alphabet)
4. Construct: http://www.plantuml.com/plantuml/svg/{encoded}

Limit: ~2000 chars (browser limit). For larger diagrams, output source only.

Integration Points

Limitations (Phase 1)

• Internet required for rendering
• URL length ~2000 chars
• Code visible to public PlantUML server
• No caching

End of Skill Document