MDG v1.0 — Public Release

MDG v1.0 — Mermaid Diagram Guidelines

A skill file that makes LLMs dramatically better at generating Mermaid diagrams.

What's included

• Single file (SKILL.md) — drop into any LLM's system prompt or Claude Project
• 10 Emergency Rules preventing the most common Mermaid syntax and rendering failures
• 6 Layout Techniques (T1–T6) — side-by-side, stacked, grid, hub-and-spoke, and more
• Page-Fit Strategy — cross-grain direction + subgraph-level connections for compact, readable output
• 8 Diagram Types — flowchart, sequenceDiagram, erDiagram, stateDiagram-v2, classDiagram, gantt, mindmap, pie
• Color Palettes — standard, subgraph backgrounds, and color-blind friendly variants (WCAG 2.1 AA)
• Dual Mode — Diagram Mode (human visual) and RAG Mode (knowledge-graph extraction)
• Pre-Publish Checklist — catch broken diagrams before delivery
• Layout Troubleshooting — symptom → cause → fix table for common rendering issues
• ELK Layout Engine reference for advanced use cases

Development history

Developed over 12 months (v0.38d1 → v1.0). Validated through 4 rounds of structured multi-LLM peer review with 5 reviewer models: GPT, Gemini, Grok, Claude Sonnet, and Claude Haiku.

Quick start

1. Download SKILL.md
2. Add to your Claude Project (or paste into any LLM's system prompt)
3. Ask for a Mermaid diagram — it will follow MDG conventions automatically