PlantUML Diagram Generator

Generate diagrams from text descriptions using PlantUML.

Execution

Use the wrapper script scripts/generate-diagram.sh:

# File-based (creates .png next to .puml, reports output path)
./scripts/generate-diagram.sh diagram.puml

# SVG output
./scripts/generate-diagram.sh --svg diagram.puml

# Pipe mode
echo '@startuml
Alice -> Bob: Hello
@enduml' | ./scripts/generate-diagram.sh --pipe > output.png

The script validates input files exist and reports generated file paths on success. After generating, use the Read tool to display the image to the user.

Diagram Types

UML Diagrams (@startuml/@enduml)

Type	Key Syntax
Sequence	A -> B: msg, A --> B: response (dashed), A ->> B: async
Class	class Name { +public() \n -private \n #protected }
Activity	:action;, if (cond) then (yes) else (no) endif, start/stop
State	[*] --> State1, State1 --> State2 : event
Use Case	actor User, usecase (Login), User --> (Login)
Component	component [Name], [A] --> [B]
Deployment	node Server { artifact App }

Non-UML Diagrams

Type	Start/End Tags	Example
Mind Map	@startmindmap/@endmindmap	* Root \n ** Branch \n *** Leaf
Gantt	@startgantt/@endgantt	[Task] requires 5 days
ER	@startuml	entity User { *id : int }
JSON	@startjson/@endjson	Direct JSON visualization
YAML	@startyaml/@endyaml	Direct YAML visualization

C4 Architecture Diagrams

Include the appropriate level:

!include <C4/C4_Context>    ' Level 1: System Context
!include <C4/C4_Container>  ' Level 2: Containers
!include <C4/C4_Component>  ' Level 3: Components

Key macros:

• Person(alias, "Label", "Description")
• System(alias, "Label", "Description") / System_Ext() for external
• Container(alias, "Label", "Tech", "Description") / ContainerDb() for databases
• Component(alias, "Label", "Tech", "Description")
• System_Boundary(alias, "Label") { ... } / Container_Boundary()
• Rel(from, to, "Label", "Tech") for relationships
• SHOW_LEGEND() at end for legend

Quick Reference

See references/syntax.md for complete syntax examples of all diagram types.

Output Formats

Flag	Format
(default)	PNG
--svg	SVG (scalable)
--pdf	PDF
--txt	ASCII art
--utxt	Unicode ASCII art

Workflow

1. Write .puml file with diagram code
2. Run ./scripts/generate-diagram.sh file.puml
3. If error, check stderr for syntax issues (usually line numbers and descriptions)
4. Use Read tool to display resulting image to user

Notes

Script Execution: Scripts should be executed from the skill directory or with full paths. They use Nix shebangs so no manual dependency installation is required.