Mermaid Diagrams

If you're documenting systems, modeling domains, or explaining architecture, this gives Claude the full Mermaid syntax reference to generate diagrams from text. It covers class diagrams for domain models, sequence diagrams for API flows, flowcharts for processes, ERDs for database schemas, and C4 diagrams for architecture. The detailed references walk through relationship types, cardinality notation, and styling options. Honestly, the main value is having all the syntax rules in one place so Claude doesn't hallucinate invalid Mermaid code. Works well when you need diagrams that live in version control alongside your code instead of rotting in some separate diagramming tool.

skills.sh installs: 5.2K
GitHub stars: 2.7K
last updated: Aug 21, 2026

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Install

$ npx -y skills add softaworks/agent-toolkit --skill mermaid-diagrams --agent claude-code

Installs into .claude/skills of the current project.

Files

Mermaid Diagramming

Create professional software diagrams using Mermaid's text-based syntax. Mermaid renders diagrams from simple text definitions, making diagrams version-controllable, easy to update, and maintainable alongside code.

Core Syntax Structure

All Mermaid diagrams follow this pattern:

diagramType
  definition content

Key principles:

First line declares diagram type (e.g., classDiagram, sequenceDiagram, flowchart)
Use %% for comments
Line breaks and indentation improve readability but aren't required
Unknown words break diagrams; parameters fail silently

Diagram Type Selection Guide

Choose the right diagram type:

Class Diagrams - Domain modeling, OOP design, entity relationships
- Domain-driven design documentation
- Object-oriented class structures
- Entity relationships and dependencies
Sequence Diagrams - Temporal interactions, message flows
- API request/response flows
- User authentication flows
- System component interactions
- Method call sequences