create-code-diagram

name	create-code-diagram
description	Generate a full code-level Mermaid class diagram of the entire project. Shows all classes, interfaces, relationships, dependencies, and inheritance. Output saved to .atl/docs/code-diagram.md
argument-hint	[output-path]

/create-code-diagram Skill

Purpose

Generates a comprehensive Mermaid class diagram of the entire project's codebase. Shows every class, interface, entity, handler, service — and how they relate to each other (inheritance, implementation, dependency, composition).

This is for humans — when you want to see the full picture, understand the system, or debug your mental model of the architecture.

Flow

1. Scan the Codebase

Use codebase-memory-mcp (if available) or direct file scanning to discover:

• All classes, records, interfaces, enums, abstract classes
• Inheritance relationships (class extends base)
• Interface implementations (class implements interface)
• Dependencies (constructor injection, method parameters)
• Composition (class has property of another class type)
• Mediator handlers and which commands/queries they handle

2. Organize by Layer

Group discovered types by architectural layer:

%% Domain Layer
%% Application Layer — Interfaces
%% Application Layer — Features
%% Infrastructure Layer
%% API Layer — Endpoints

For each layer, list all types with their key members (properties for entities, methods for services/handlers).

3. Map Relationships

For each type, determine relationships:

Relationship	Mermaid Syntax	When
Inheritance	`Child --	> Parent`
Implementation	Impl ..|> Interface	class implements interface
Dependency	ClassA --> ClassB	constructor injection, method call
Composition	ClassA *-- ClassB	has property of type ClassB
Association	ClassA o-- ClassB	collection of ClassB

4. Generate Mermaid Diagram

Create a complete classDiagram in Mermaid format. Include:

• Every class/interface with key members
• Every relationship with correct arrow type
• Layer grouping with %% comments
• Namespace grouping where applicable

5. Write to File

Default output: .atl/docs/code-diagram.md

If an output path is provided as argument, use that instead.

File format:

# Code Diagram

> Auto-generated by /create-code-diagram on {date}
> Re-run `/create-code-diagram` to update after code changes.

## Full Project Diagram

{mermaid diagram here}

## Legend

| Symbol | Meaning |
|--------|---------|
| `--|>` | Inherits from |
| `..\|>` | Implements interface |
| `-->` | Depends on (injected) |
| `*--` | Contains (composition) |
| `o--` | Has collection of |

## Statistics

- Total types: {count}
- Classes: {count}
- Interfaces: {count}
- Records: {count}
- Relationships: {count}
- Generated: {timestamp}

6. Report

Tell the user:

• File created/updated at {path}
• Number of types and relationships discovered
• "Open in GitHub or VS Code Mermaid preview to view the diagram"

Diagram Template

classDiagram
    %% ═══════════════════════════════════════
    %% DOMAIN LAYER
    %% ═══════════════════════════════════════

    class BaseEntity {
        +Guid Id
        +DateTime CreatedAt
        +DateTime? UpdatedAt
        +uint RowVersion
    }

    class IAuditableEntity {
        <<interface>>
        +string? CreatedBy
        +DateTime? ModifiedAt
        +string? ModifiedBy
    }

    class ISoftDeletable {
        <<interface>>
        +bool IsDeleted
        +DateTime? DeletedAt
        +string? DeletedBy
    }

    class User {
        +string Email
        +string PasswordHash
        +string? FirstName
        +string? LastName
    }
    User --|> BaseEntity
    User ..|> IAuditableEntity
    User ..|> ISoftDeletable

    %% ═══════════════════════════════════════
    %% APPLICATION LAYER — INTERFACES
    %% ═══════════════════════════════════════

    class IApplicationDbContext {
        <<interface>>
        +DbSet~User~ Users
        +SaveChangesAsync()
    }

    class ITokenService {
        <<interface>>
        +GenerateAccessToken()
        +GenerateRefreshToken()
    }

    class IEmailSender {
        <<interface>>
        +SendAsync()
    }

    %% ... (all interfaces)

    %% ═══════════════════════════════════════
    %% APPLICATION LAYER — FEATURES
    %% ═══════════════════════════════════════

    class PingHandler {
        +Handle(PingQuery)
    }
    PingHandler --> IApplicationDbContext

    %% ... (all handlers with their dependencies)

    %% ═══════════════════════════════════════
    %% INFRASTRUCTURE LAYER
    %% ═══════════════════════════════════════

    class ApplicationDbContext {
        +DbSet~User~ Users
    }
    ApplicationDbContext ..|> IApplicationDbContext

    class JwtTokenService
    JwtTokenService ..|> ITokenService

    class RmqEmailSender
    RmqEmailSender ..|> IEmailSender

    %% ... (all implementations)

    %% ═══════════════════════════════════════
    %% API LAYER
    %% ═══════════════════════════════════════

    class HealthEndpoints {
        +MapHealthEndpoints()
    }
    HealthEndpoints --> IMediator

Important Rules

1. Include EVERYTHING. Don't skip small classes or "obvious" relationships. The user wants the full picture.
2. Group by layer. Domain → Application Interfaces → Application Features → Infrastructure → API/Socket/Worker.
3. Show key members. Properties for entities, methods for services/handlers. Don't list every private field.
4. Correct arrow types. Inheritance vs implementation vs dependency — use the right Mermaid syntax.
5. Re-runnable. Running again overwrites the previous diagram. Always fresh.
6. No external tools needed. Pure Mermaid markdown — viewable in GitHub, VS Code, any markdown renderer.

Accumulated Learnings

(Auto-rebuilt by /save-learnings from learnings/*.md frontmatter. Do not edit by hand. Currently empty — populates as the skill is used and edge-case learnings accumulate.)