mermaid

name	mermaid
description	Create, edit, validate, and render Mermaid diagrams (.mmd or Mermaid blocks in Markdown/HTML). Use when asked to convert visuals or specs into Mermaid, fix Mermaid syntax errors, add labels/line breaks, or render SVG/PNG via mmdc or a Mermaid CDN.

Mermaid

Overview

Convert specs or images into accurate Mermaid diagrams, preserving as many details as possible (labels, casing, punctuation, and annotations), validate syntax, and render SVG/PNG with mmdc (preferred) or CDN-backed HTML when requested.

Workflow

1) Capture the source of truth

• Extract every node, edge, label, and annotation from the input (image, notes, or code); preserve as many details as possible, including exact casing, punctuation, and any callout notes.
• Preserve naming, casing, and arrow direction; note any ambiguous text for follow-up.

2) Draft Mermaid accurately

• Pick the diagram type explicitly (e.g., flowchart LR, sequenceDiagram).
• Use clear node IDs and keep labels faithful to the source, including exact casing and separators.
• Use HTML line breaks in labels: <br/>.
• Escape literal pipes in labels as |.
• If a labeled reverse arrow causes parse issues, flip the edge direction and keep the label on a forward arrow.
• Add layout hints only when needed (e.g., subgraphs, direction, or invisible edges), but never at the expense of label fidelity.

3) Validate and render with mmdc (preferred)

• If mmdc needs a Chrome path, create a Puppeteer config like:
  • {"executablePath": "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"}
• Render and validate in one step:
  • mmdc -p /tmp/puppeteer-config.json -i <input.mmd> -o <output.svg>
• Fix any syntax errors reported by mmdc before delivering output.

4) Deliver outputs

• Provide the final .mmd and rendered .svg (or .png) in the requested directory.
• Open the rendered asset in Chrome when asked.
• Only create HTML + CDN when explicitly requested or when mmdc is unavailable.

Common Fixes

• | inside labels: replace with |.
• Multi-line labels: use <br/> (not \n).
• Edge labels: A -->|label| B.
• Node labels containing brackets or punctuation: wrap in "..." if parsing is unstable.

Resources

references/

• references/mermaid-notes.md: quick syntax/escaping tips and rendering notes.