generate-db-diagram

name	generate-db-diagram
description	Generate database diagram for a feature
argument-hint	["feature-name"]
disable-model-invocation	true
allowed-tools	Bash(npx *)

Generate Database Diagram

Generate a Mermaid class diagram representing the database schema related to: $ARGUMENTS

Instructions

1. Identify Relevant Models/Tables

Search the codebase for models, entities, or schema definitions related to the specified feature.

Guidelines

• Focus on the core tables/models needed to understand the feature's data structure
• If a feature has many related models, prioritize the most important ones
• If uncertain about which models to include, err on the side of including related models
• Search thoroughly through the codebase to find all relevant schema definitions

2. Generate Mermaid Diagram

Follow these rules:

• Use Mermaid class diagram syntax
• Include only models directly related to the feature
• Show only important fields (exclude: id, created_at, updated_at, timestamps unless critical)
• Do NOT include field types UNLESS it's a relationship field
• For relationship fields, show them as:
  • FK to ModelName (foreign key / belongs to)
  • O2O to ModelName (one-to-one)
  • M2M to ModelName (many-to-many)
• Show relationships between models using Mermaid relationship syntax:
  • Model1 "1" --> "many" Model2 : relationship_name
  • Model1 "1" --> "1" Model2 : relationship_name
  • Model1 "many" --> "many" Model2 : relationship_name
• Keep it clean and focused on the feature's data structure

Example Output

classDiagram
    class Project {
        name
        description
        status
        owner FK to User
    }

    class Task {
        title
        completed
        project FK to Project
        assignee FK to User
    }

    class User {
        email
        name
    }

    Task "many" --> "1" Project : project
    Task "many" --> "1" User : assignee
    Project "many" --> "1" User : owner

3. Generate the Diagram Image

• Create a PNG image: .claude/outputs/db-diagram-<feature-name>.png (use kebab-case)
• Create the .claude/outputs/ directory with a .gitkeep if it doesn't exist
• No temporary files needed - pipe directly to mermaid-cli

Steps

1. Pipe the Mermaid class diagram code directly to npx @mermaid-js/mermaid-cli using stdin:

   mkdir -p .claude/outputs && touch .claude/outputs/.gitkeep && cat << 'EOF' | npx -y @mermaid-js/mermaid-cli -i - -o .claude/outputs/db-diagram-<feature-name>.png
   classDiagram
       class Project {
           name
           description
           status
           owner FK to User
       }
   
       class Task {
           title
           completed
           project FK to Project
           assignee FK to User
       }
   
       class User {
           email
           name
       }
   
       Task "many" --> "1" Project : project
       Task "many" --> "1" User : assignee
       Project "many" --> "1" User : owner
   EOF
   

2. Inform the user that the diagram has been created at .claude/outputs/db-diagram-<feature-name>.png