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Must read guide on creating/editing mermaid charts with valiation tools

mitsuhiko By mitsuhiko schedule Updated 2/5/2026

name: mermaid description: "Must read guide on creating/editing mermaid charts with valiation tools"

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.
Install via CLI
npx skills add https://github.com/mitsuhiko/agent-stuff --skill mermaid
Repository Details
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