Mermaid-cli is a command line interface and programmatic tool that converts text-based diagram syntax into static visual assets. It functions as a headless browser renderer and markdown diagram processor, enabling the generation of diagrams through a CLI or a JavaScript-based generator.
The tool distinguishes itself by supporting the conversion of diagram definitions into multiple image formats, including SVG, PNG, and PDF. It allows for custom diagram styling by applying external CSS files to override default themes and add visual animations.
The project provides capabilities for markdown integration, where it scans files to replace diagram blocks with rendered images. It also supports automation workflows through standard input processing, allowing diagram definitions to be piped directly into the rendering engine.