Nm Cartograph Class Diagram

Generate class diagrams showing classes, interfaces, inheritance, and composition

Security Scan

The skill's inputs, instructions, and external calls are consistent with its stated purpose of generating class diagrams from a codebase; it does not request unrelated credentials or installs.

Purpose & Capability

Name/description (generate class diagrams) matches the instructions: explore a codebase, extract types/relationships, generate Mermaid, and render. No unrelated binaries, env vars, or installs are requested.

Instruction Scope

Instructions explicitly dispatch a 'codebase-explorer' agent to read the codebase and then call a Mermaid Chart MCP to render the diagram. Reading repository files and sending generated mermaid code to a rendering service are expected for this purpose, but they do mean the skill will access source files and transmit diagram data to the platform renderer.

Install Mechanism

Instruction-only skill with no install steps or downloaded code. Lowest-risk install posture.

Credentials

No environment variables, credentials, or config paths are requested; the declared requirements are proportional to the stated functionality.

Persistence & Privilege

No 'always: true' or other elevated persistence requested. The skill is user-invocable and does not request system-wide changes.

Assessment

This skill appears coherent and does what it says: it will examine your codebase (via a codebase-explorer agent) to extract types/relationships and then send generated Mermaid code to the platform's Mermaid Chart renderer. Before installing or running it on private repositories, confirm you are comfortable granting the agent read access to the repository and that sending diagram content to the platform renderer is acceptable for your data sensitivity. Avoid embedding secrets or sensitive tokens in code snippets you expect the tool to analyze; if you need stricter privacy, run an offline or self-hosted diagramming workflow instead.

Night Market Skill — ported from claude-night-market/cartograph. For the full experience with agents, hooks, and commands, install the Claude Code plugin.

Class Diagram

Generate a Mermaid class diagram showing types, their relationships, and public interfaces from a codebase.

When To Use

• Understanding class hierarchies and inheritance
• Documenting public APIs of a module
• Analyzing composition vs. inheritance patterns
• Answering "what types exist and how do they relate?"

Workflow

Step 1: Explore the Codebase

Dispatch the codebase explorer agent:

Agent(cartograph:codebase-explorer)
Prompt: Explore [scope] and return a structural model.
Focus on classes, dataclasses, protocols, type aliases,
inheritance, and composition for a class diagram.
Extract: class names, methods (public only), attributes,
parent classes, and composed types.

Step 2: Generate Mermaid Syntax

Transform the structural model into a Mermaid class diagram.

Rules for class diagrams:

• Use classDiagram diagram type
• Show only public methods and key attributes
• Use Mermaid relationship notation:
  • <|-- for inheritance
  • *-- for composition
  • o-- for aggregation
  • ..> for dependency/usage
• Add stereotypes for special types:
  • <<protocol>> for Python protocols/interfaces
  • <<dataclass>> for dataclasses
  • <<enum>> for enums
  • <<abstract>> for abstract classes
• Limit to 12-15 classes maximum
• Group related classes with namespace
• Omit private methods and dunder methods
• Show return types for methods

Example output:

classDiagram
    class ResumeSession {
        +Path config_path
        +dict data
        +load() ResumeSession
        +to_pdf(Path) Path
        +to_html(Path) Path
    }

    class ResumeError {
        <<abstract>>
        +str message
        +str context
    }

    class ValidationError {
        +list~str~ fields
    }

    class RenderError {
        +str template
    }

    ResumeError <|-- ValidationError
    ResumeError <|-- RenderError
    ResumeSession ..> ResumeError

Step 3: Render via MCP

Call the Mermaid Chart MCP to render:

mcp__claude_ai_Mermaid_Chart__validate_and_render_mermaid_diagram
  prompt: "Class diagram of [scope]"
  mermaidCode: [generated syntax]
  diagramType: "classDiagram"
  clientName: "claude-code"

If rendering fails, fix syntax and retry (max 2 retries).

Step 4: Present Results

Show the rendered diagram with analysis notes:

• Total classes and relationship count
• Key inheritance hierarchies identified
• Composition patterns noted