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mermaid-diagrams

Design
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Render Mermaid diagrams to SVG using beautiful-mermaid and bun. Use when the user asks to "render mermaid", "generate diagram", "create flowchart", "update diagrams", "render SVG from mermaid", "beautiful-mermaid", "regenerate diagrams", or needs to convert Mermaid diagram syntax into styled SVG files. Supports all Mermaid diagram types with 15 themes including tokyo-night.

QUICK START

How to use this skill

Bring this guide into your coding agent with a prompt tailored to the tool you use.

  1. Open your project in Codex.
  2. Copy the prompt below and paste it into your agent.
  3. Review the proposed files and risks before you approve installation.
Prompt to paste
I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/majiayu000/claude-skill-registry/blob/HEAD/skills/design/mermaid-diagrams-ahundt-autorun/SKILL.md

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First, summarize what it does, its dependencies, license status if identifiable, and any risks. Show the exact files you propose to add under .agents/skills/mermaid-diagrams/. Do not write files or run scripts until I approve.

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

Mermaid Diagram Rendering with beautiful-mermaid

Render Mermaid .mmd files into styled SVG using beautiful-mermaid v1.0.2 and bun.

Skill Contents

FilePurpose
render-mermaid.tsCLI tool: renders .mmd files to SVG
gemini-diagram-prompt.mdPrompt for Gemini image generation

Installation

Only bun is required. The beautiful-mermaid dependency is auto-installed by bun on first run.

# macOS
brew install oven-sh/bun/bun

# Or universal installer
curl -fsSL https://bun.sh/install | bash

CLI Reference

render-mermaid — Render Mermaid .mmd files to themed SVG

Usage:
  bun run render-mermaid.ts [options] <input.mmd...>
  echo 'graph TD; A-->B' | bun run render-mermaid.ts -o out.svg

Options:
  -o, --output <file>   Output file (single input only)
  --outdir <dir>        Output directory for multiple files
  -t, --theme <name>    Theme (default: tokyo-night)
  --list-themes         List available themes
  --help                Show this help

Output defaults: Without -o or -d, writes <name>.svg next to each input file.

Shorthand: Set MERMAID=plugins/autorun/skills/mermaid-diagrams/render-mermaid.ts for shorter commands.

Examples

MERMAID=plugins/autorun/skills/mermaid-diagrams/render-mermaid.ts

# Render single file (output next to input)
bun run $MERMAID diagram.mmd

# Render to specific output
bun run $MERMAID diagram.mmd -o pretty.svg

# Render all .mmd files to output directory
bun run $MERMAID docs/diagrams/*.mmd --outdir docs/diagrams

# Different theme
bun run $MERMAID -t dracula diagram.mmd

# Pipe from stdin
echo 'graph TD; A-->B-->C' | bun run $MERMAID -o quick.svg

# List themes
bun run $MERMAID --list-themes

Project Diagrams

Mermaid source files (.mmd) and rendered output (.svg) in docs/diagrams/:

SourceDescription
docs/diagrams/autofile-policy.mmdAutoFile policy flowchart
docs/diagrams/three-stage-autorun.mmdThree-stage autorun flowchart
autorun-architecture.mmdFull architecture (too complex for beautiful-mermaid)

Regenerate:

bun run $MERMAID docs/diagrams/*.mmd --outdir docs/diagrams

Known Limitations

  • Complex diagrams with deeply nested subgraphs may hit dagre layout bugs. Failed diagrams are reported but don't block other renders.
  • %%{init:...}%% front matter is stripped automatically (beautiful-mermaid applies its own theming).

Gemini Image Generation

gemini-diagram-prompt.md contains a prompt for Gemini to generate an outcome-focused project overview image. Copy the prompt into a Gemini conversation.