GitHub - iishyfishyy/mermaid-live-mcp

MCP server for generating Mermaid diagrams with live browser preview. Renders diagrams in real-time and supports SVG/PNG export.

Install

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "mermaid": {
      "command": "npx",
      "args": ["-y", "mermaid-live-mcp"]
    }
  }
}

Cursor

Add to .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "mermaid": {
      "command": "npx",
      "args": ["-y", "mermaid-live-mcp"]
    }
  }
}

Claude Code

claude mcp add mermaid -- npx -y mermaid-live-mcp

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "mermaid": {
      "command": "npx",
      "args": ["-y", "mermaid-live-mcp"]
    }
  }
}

Tools

Tool	Description
`generate_mermaid`	Generate a diagram from Mermaid syntax and open a live preview in the browser
`update_diagram`	Replace a diagram's Mermaid syntax and re-render the live preview
`list_diagrams`	List all diagrams generated in the current session
`export_diagram`	Write a diagram's SVG to disk

How it works

When you ask your AI assistant to create a diagram, mermaid-live-mcp will:

Parse the Mermaid syntax
Open a browser tab with a live preview
Render the diagram as SVG in real-time via WebSocket
Provide download buttons for SVG and PNG export

Updates to a diagram are pushed instantly to the browser — no page refresh needed.

Supported diagram types

All Mermaid diagram types are supported, including flowcharts, sequence diagrams, class diagrams, state diagrams, ER diagrams, Gantt charts, pie charts, git graphs, mindmaps, timelines, and more.

Development

Project structure

Package	Description
`packages/mcp-server`	MCP server (published as `mermaid-live-mcp`)
`packages/preview`	Live browser preview via WebSocket
`packages/core`	Diagram parsing, layout, and SVG rendering
`packages/cli`	Command-line interface

License

MIT