Generate Mermaid Diagram

Overview

Analyze the provided code, architecture, or concept and generate a clear, well-structured Mermaid diagram that visualizes the relationships, flow, or structure.

Instructions

1. Analyze the input - Understand what the user wants to visualize (code flow, architecture, data relationships, state machines, sequences, etc).

2. Choose the appropriate diagram type:

   • flowchart - For process flows, decision trees, algorithms
   • sequenceDiagram - For API calls, message passing, request/response flows
   • classDiagram - For class structures, inheritance, interfaces
   • erDiagram - For database schemas, entity relationships
   • stateDiagram-v2 - For state machines, lifecycle flows
   • graph TD/LR - For dependency graphs, module relationships
   • gitgraph - For git branching strategies
   • journey - For user journeys
   • gantt - For timelines and schedules

3. Generate the diagram with these qualities:

   • Clear, descriptive node labels
   • Logical grouping with subgraphs where appropriate
   • Consistent styling and direction
   • Meaningful relationship labels on edges
   • Not overly complex - split into multiple diagrams if needed

4. Output format: Always wrap the diagram in a mermaid code block:

   [diagram code here]
   

Diagram Style Guidelines

• Use descriptive IDs: userService not a1
• Add labels to relationships when they add clarity
• Use subgraphs to group related components
• Keep diagrams readable - max ~15-20 nodes per diagram
• Use appropriate arrow styles:
• --> solid arrow (main flow)
• -.-> dotted arrow (optional/async)
• ==> thick arrow (important path)
• o--> circle end (aggregation)
• *--> diamond end (composition)

Examples

Flowchart

flowchart TD
    A[Start] --> B{Is valid?}
    B -->|Yes| C[Process]
    B -->|No| D[Error]
    C --> E[End]
    D --> E

Sequence Diagram

sequenceDiagram
    participant C as Client
    participant S as Server
    participant DB as Database

    C->>S: Request
    S->>DB: Query
    DB-->>S: Results
    S-->>C: Response

Class Diagram

classDiagram
    class Animal {
         String name
         makeSound()
    }
    class Dog {
         bark()
    }
    Animal <|-- Dog

ER Diagram

erDiagram
    USER ||--o{ ORDER : places
    ORDER ||--|{ LINE_ITEM : contains
    PRODUCT ||--o{ LINE_ITEM : "ordered in"

After generating

• Explain what the diagram shows
• Offer to refine or expand specific sections
• Suggest alternative diagram types if applicable