diagram

name	diagram
description	Create PlantUML diagrams and add them to documentation
argument-hint	[diagram type] [description or target file]
allowed-tools	Bash, Read, Edit, Write, Glob

Create a PlantUML diagram and optionally add it to a markdown file.

Usage

• /diagram sequence user login flow - Create a sequence diagram
• /diagram component for README.md - Create a component diagram and add to README
• /diagram class data models - Create a class diagram

Steps

1. Determine diagram type from arguments:

   • sequence - Interactions between actors/systems
   • component - System architecture and dependencies
   • class - Data models and relationships
   • activity - Workflows and decision flows
   • state - State machines

2. Create the PlantUML syntax appropriate for the type

3. Generate URLs using the plantuml plugin MCP server:

   cd /path/to/plugins/plantuml && printf '%s\n%s\n%s\n' \
     '{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"claude","version":"1.0"}}}' \
     '{"jsonrpc":"2.0","method":"notifications/initialized"}' \
     '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"plantuml_generate_urls","arguments":{"diagram":"..."}}}' \
     | python3 main.py
   

4. If a target file is specified, add the diagram to it:

   • Insert image as a clickable link to the editor: [![description](png-url)](editor-url)
   • The alt text should be a human-friendly summary of what the diagram shows
   • The PNG renders inline in documentation; clicking it opens the PlantUML editor
   • Do NOT add <details> blocks or other non-standard markdown

5. Show the user:

   • The generated URLs (png, svg, editor)
   • The PlantUML source code

Diagram Templates

Sequence

@startuml
actor User
participant "System A" as A
participant "System B" as B

User -> A: request
A -> B: process
B --> A: response
A --> User: result
@enduml

Component

@startuml
package "System" {
  [Component A] as A
  [Component B] as B
}
A --> B : uses
@enduml

Class

@startuml
class Entity {
  +id: string
  +name: string
  +save(): void
}
@enduml

Output Format

When adding to a file, use a linked image with descriptive alt text. Do NOT include <details> blocks or inline PlantUML source — the editor link serves as the source reference:

[![Human-friendly description of what the diagram shows](https://www.plantuml.com/plantuml/png/~1...)](https://www.plantuml.com/plantuml/uml/~1...)