305s/diagram-creator

Diagram Creator Skill

Overview

I help you create professional diagrams using text-based diagram tools like Mermaid and PlantUML. These diagrams can be rendered in documentation, presentations, and development tools.

What I can do:

• Create flowcharts and process diagrams
• Generate sequence diagrams
• Build architecture and system diagrams
• Design ER (Entity-Relationship) diagrams
• Create class diagrams and UML
• Generate organizational charts
• Build Gantt charts and timelines

What I cannot do:

• Render images directly (use Mermaid live editor or similar)
• Create pixel-perfect custom designs
• Generate raster images

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How to Use Me

Step 1: Describe Your Diagram

Tell me:

• What process/system/concept to visualize
• Type of diagram needed
• Level of detail
• Target audience

Step 2: Choose Format

• Mermaid: Best for web, markdown, GitHub
• PlantUML: Best for UML, complex diagrams
• ASCII: Simple, universal compatibility
• D2: Modern, stylish diagrams

Step 3: Specify Style

• Colors and themes
• Direction (top-down, left-right)
• Level of detail

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Diagram Types

1. Flowchart / Process Diagram

Use for: Business processes, decision trees, workflows

flowchart TD
    A[Start] --> B{Decision?}
    B -->|Yes| C[Action 1]
    B -->|No| D[Action 2]
    C --> E[End]
    D --> E

2. Sequence Diagram

Use for: API calls, user interactions, system communication

sequenceDiagram
    participant U as User
    participant A as App
    participant S as Server
    participant D as Database
    
    U->>A: Click Login
    A->>S: POST /auth/login
    S->>D: Query user
    D-->>S: User data
    S-->>A: JWT token
    A-->>U: Redirect to dashboard

3. Architecture Diagram

Use for: System design, infrastructure, component relationships

flowchart TB
    subgraph Client
        A[Web App]
        B[Mobile App]
    end
    
    subgraph Backend
        C[API Gateway]
        D[Auth Service]
        E[User Service]
        F[Order Service]
    end
    
    subgraph Data
        G[(PostgreSQL)]
        H[(Redis)]
        I[(S3)]
    end
    
    A & B --> C
    C --> D & E & F
    D --> H
    E --> G
    F --> G & I

4. Entity-Relationship Diagram

Use for: Database design, data models

erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ LINE_ITEM : contains
    PRODUCT ||--o{ LINE_ITEM : "ordered in"
    
    CUSTOMER {
        int id PK
        string name
        string email
    }
    ORDER {
        int id PK
        date created_at
        int customer_id FK
    }
    PRODUCT {
        int id PK
        string name
        decimal price
    }

5. Class Diagram

Use for: OOP design, code structure

classDiagram
    class Animal {
        +String name
        +int age
        +makeSound()
    }
    class Dog {
        +String breed
        +bark()
    }
    class Cat {
        +boolean indoor
        +meow()
    }
    
    Animal <|-- Dog
    Animal <|-- Cat

6. State Diagram

Use for: State machines, status workflows

stateDiagram-v2
    [*] --> Draft
    Draft --> Submitted: Submit
    Submitted --> InReview: Assign reviewer
    InReview --> Approved: Approve
    InReview --> Rejected: Reject
    Rejected --> Draft: Revise
    Approved --> [*]

7. Gantt Chart

Use for: Project timelines, schedules

gantt
    title Project Timeline
    dateFormat  YYYY-MM-DD
    
    section Planning
    Requirements    :a1, 2024-01-01, 14d
    Design          :a2, after a1, 21d
    
    section Development
    Backend         :b1, after a2, 30d
    Frontend        :b2, after a2, 30d
    
    section Testing
    QA Testing      :c1, after b1, 14d
    UAT             :c2, after c1, 7d

8. Mind Map

Use for: Brainstorming, concept organization

mindmap
    root((Project))
        Features
            Feature A
            Feature B
            Feature C
        Team
            Frontend
            Backend
            Design
        Timeline
            Q1
            Q2
            Q3

9. Git Graph

Use for: Branch visualization, git workflows

gitGraph
    commit
    commit
    branch feature
    checkout feature
    commit
    commit
    checkout main
    merge feature
    commit

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Output Format

# Diagram: [Name]

**Type**: [Flowchart / Sequence / Architecture / etc.]
**Tool**: [Mermaid / PlantUML]
**Purpose**: [What it illustrates]

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## Diagram Code

### Mermaid

```mermaid
[Mermaid code here]

PlantUML (Alternative)

[PlantUML code here]

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Rendering Instructions

1. Mermaid Live Editor: https://mermaid.live/
2. GitHub: Paste directly in markdown files
3. VS Code: Install Mermaid extension
4. Notion: Use code block with mermaid type

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Customization Options

Color Theme

Add to the beginning:

%%{init: {'theme':'forest'}}%%

Available themes: default, forest, dark, neutral

Direction

• TB (top to bottom)
• BT (bottom to top)
• LR (left to right)
• RL (right to left)

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Notes

• [Any notes about the diagram]
• [Assumptions made]

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## PlantUML Examples

### Sequence Diagram
```plantuml
@startuml
actor User
participant "Web App" as App
participant "API Server" as API
database "Database" as DB

User -> App: Login request
App -> API: POST /auth/login
API -> DB: SELECT user
DB --> API: User record
API --> App: JWT token
App --> User: Redirect to dashboard
@enduml

Component Diagram

@startuml
package "Frontend" {
    [React App]
    [Mobile App]
}

package "Backend" {
    [API Gateway]
    [Auth Service]
    [User Service]
}

database "PostgreSQL" as DB

[React App] --> [API Gateway]
[Mobile App] --> [API Gateway]
[API Gateway] --> [Auth Service]
[API Gateway] --> [User Service]
[User Service] --> DB
@enduml

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Tips for Better Diagrams

1. Keep it simple - Don't overcrowd
2. Use consistent naming - Clear, descriptive labels
3. Group related items - Use subgraphs/packages
4. Choose appropriate type - Match diagram to concept
5. Consider audience - Technical vs. business
6. Use colors sparingly - For emphasis only
7. Add legends - When using symbols/colors
8. Maintain hierarchy - Top-down or left-right flow

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Rendering Tools

| Tool | URL | Best For | |------|-----|----------| | Mermaid Live | mermaid.live | Quick editing | | PlantUML Server | plantuml.com | PlantUML rendering | | Draw.io | draw.io | Manual editing | | Excalidraw | excalidraw.com | Hand-drawn style | | Lucidchart | lucidchart.com | Professional diagrams |

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Limitations

• Cannot render images directly
• Complex layouts may need manual adjustment
• Limited styling compared to design tools
• Some diagram types not supported in all tools

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Built by the Claude Office Skills community. Contributions welcome!