Mermaid Image Export

Mermaid diagram image export using mermaid-cli. When Claude needs to export Mermaid diagrams as high-quality images (PNG, SVG, PDF) for documentation, presen...

Security Scan

The skill's documentation and scripts are consistent with a mermaid-cli exporter, but the registry metadata and declared requirements omit the Node/Chrome/mermaid-cli dependencies and the package includes scripts that run local installs and subprocesses — this mismatch and the runtime actions deserve caution before installing.

Purpose & Capability

The skill's name and SKILL.md describe a mermaid-cli image exporter and included scripts (export_mermaid_image.py, install_mermaid_cli.py, batch_export.sh) implement that purpose. However the registry metadata lists no required binaries or environment variables while the documentation repeatedly requires Node.js, npm, mermaid-cli (mmdc) and Chrome/Chromium. The omission in declared requirements is an inconsistency worth noting.

Instruction Scope

Runtime instructions are focused on exporting diagrams via mermaid-cli/Puppeteer and reference creating temporary .mmd files, running mmdc (or npx mmdc) and setting env vars like PUPPETEER_EXECUTABLE_PATH, MMDC_TIMEOUT, NODE_OPTIONS, and PUPPETEER_ARGS. The instructions do not direct data to external endpoints or request credentials, but they do instruct installing global npm packages and disabling Puppeteer sandbox in CI/docker guidance (e.g., --no-sandbox), which broadens the runtime capabilities and can reduce containment.

Install Mechanism

There is no formal install spec in the registry; installation is handled by included scripts and by instructing the user to run npm install -g @mermaid-js/mermaid-cli and to install Chrome/Chromium. Using npm/global installs and Puppeteer is common for this functionality (moderate risk) but the lack of an explicit, auditable install manifest in the registry and the reliance on executing install helper scripts increases the risk compared to an instruction-only skill.

Credentials

The skill declares no required environment variables or credentials, yet documentation and code reference several env vars (PUPPETEER_EXECUTABLE_PATH, MMDC_TIMEOUT, NODE_OPTIONS, PUPPETEER_ARGS) and suggest changing PATH and npm global installs. While none are secrets, the skill asks for environment modifications and may run commands that rely on system binaries and global npm packages — the registry should have declared Node/Chrome as required binaries to match the real needs.

Persistence & Privilege

The skill does not request always:true, does not declare persistent credentials, and does not claim to modify other skills or global Claw settings. It operates via scripts invoked at runtime and therefore has normal, limited persistence/privilege for a tooling skill.

What to consider before installing

This package appears to implement a legitimate mermaid-cli exporter, but there are inconsistencies you should clear up before installing: 1) The registry metadata omits the real requirements (Node.js, npm, Chrome/Chromium, mermaid-cli). Treat the included install helper scripts as code you will run locally. 2) Inspect scripts/export_mermaid_image.py and scripts/install_mermaid_cli.py for any subprocess calls (they likely call mmdc/npx and spawn Chrome); confirm they only run expected commands and do not call unexpected network endpoints. 3) Avoid running npm global installs or running with --no-sandbox on sensitive hosts; prefer running the skill inside a sandbox/container or CI runner. 4) If you need to trust the source, verify repository links and authorship (package.json repository points to a different project). If you are not comfortable auditing the scripts, run this in an isolated environment (container or VM) or use a known mermaid-cli installation you manage yourself and configure the skill to use that (e.g., specify --mermaid-cmd 'npx mmdc' or path to your mmdc).

Mermaid CLI Image Export Skill

Professional image export skill for Mermaid diagrams using mermaid-cli. Converts Mermaid code into high-quality PNG, SVG, and PDF images suitable for documentation, presentations, and print materials.

Quick Start

Prerequisites

# Check if Node.js is installed
node --version

# Check if npm is installed
npm --version

Installation Check

python scripts/install_mermaid_cli.py --check

Basic Usage

Export a Mermaid diagram to PNG:

python scripts/export_mermaid_image.py diagram.mmd -o output.png

Export to SVG:

python scripts/export_mermaid_image.py diagram.mmd -f svg -o diagram.svg

Batch export multiple files:

python scripts/export_mermaid_image.py *.mmd -d outputs/

Core Features

Supported Formats

• PNG: Raster image, ideal for web and documents
• SVG: Vector image, scalable without quality loss
• PDF: Document format for printing and sharing

Quality Controls

• Resolution scaling (--scale)
• Background color (--background)
• Width and height constraints (--width, --height)
• Custom CSS styling (--css)

Theme Support

• All Mermaid built-in themes: default, forest, dark, neutral
• Custom theme configuration (--config)
• Dark/light mode switching

Batch Processing

• Export multiple diagrams at once
• Progress tracking and error handling
• Consistent settings across all exports

Workflow

1. Environment Setup

Ensure Node.js and mermaid-cli are installed:

npm install -g @mermaid-js/mermaid-cli

2. Diagram Creation

Create Mermaid diagrams using standard syntax.

3. Image Export

Use appropriate format based on needs:

• Web/Docs: PNG or SVG
• Print: PDF or high-resolution PNG
• Development: Quick PNG previews

4. Integration

Embed exported images in:

• README documentation
• Presentation slides
• Technical papers
• API documentation
• Blog posts

Comparison with Termaid

Feature	Termaid	Mermaid-CLI Export
Output	ASCII terminal	PNG/SVG/PDF images
Dependencies	Pure Python	Node.js + Puppeteer
Use Case	Terminal preview	Professional export
Quality	Terminal-friendly	Print-ready
Speed	Instant	Requires browser

Advanced Usage

Custom Configuration

# Custom CSS
python scripts/export_mermaid_image.py diagram.mmd --css custom.css -o output.png

# Specific theme
python scripts/export_mermaid_image.py diagram.mmd -t dark -o output.png

# High resolution
python scripts/export_mermaid_image.py diagram.mmd --scale 2.0 -o output.png

Automation

# CI/CD integration
python scripts/export_mermaid_image.py docs/*.mmd -d generated/

# Documentation generation
find . -name "*.mmd" -exec python scripts/export_mermaid_image.py {} -o images/{}.png \;

Troubleshooting

Common Issues

1. Node.js not installed: Install Node.js from nodejs.org
2. mermaid-cli not found: Run npm install -g @mermaid-js/mermaid-cli
3. Browser errors: Ensure Chrome/Chromium is installed
4. Memory issues: Reduce image size or resolution

Performance Tips

• Use lower resolution for quick previews
• Cache frequently used diagrams
• Batch process multiple diagrams
• Consider using SVG for scalability

Examples

See assets/examples/ for complete examples:

• Basic export workflow
• Configuration examples
• Template diagrams

References

Complete documentation in references/:

• overview.md: Skill overview
• installation.md: Installation guide
• usage.md: Usage instructions
• formats.md: Format specifications
• troubleshooting.md: Problem solving

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Note: This skill requires Node.js and mermaid-cli installation. For terminal-only rendering without dependencies, use the termaid skill.