Mermaid Skill

Use this skill to quickly validate Mermaid diagrams by parsing + rendering them with the official Mermaid CLI.

Prerequisites

• Node.js + npm (for npx).
• First run downloads a headless Chromium via Puppeteer. If Chromium is missing, set PUPPETEER_EXECUTABLE_PATH.

Tool

Validate a diagram

./tools/validate.sh diagram.mmd [output.svg]

• Parses and renders the Mermaid source.
• Non-zero exit = invalid Mermaid syntax.
• Prints an ASCII preview using beautiful-mermaid (best-effort; not all diagram types are supported).
• If output.svg is omitted, the SVG is rendered to a temp file and discarded.

Workflow (short)

1. If the diagram will live in Markdown: draft it in a standalone diagram.mmd first (the tool only validates plain Mermaid files).
2. Write/update diagram.mmd.
3. Run ./tools/validate.sh diagram.mmd.
4. Fix any errors shown by the CLI.
5. Once it validates, copy the Mermaid block into your Markdown file.