MCP Mermaid

What is MCP Mermaid?

MCP Mermaid is an MCP server that dynamically generates Mermaid diagrams and charts using AI. It fully supports all Mermaid features and allows configuration of background color and theme. It is designed for developers and AI agents who need to create diagrams programmatically or interactively.

How to use MCP Mermaid?

The server can be run directly via npx (e.g., npx -y mcp-mermaid) or installed globally (npm install -g mcp-mermaid) and launched with CLI options. It supports multiple transports: STDIO (default), SSE (e.g., mcp-mermaid -t sse), and Streamable HTTP (e.g., mcp-mermaid -t streamable). To integrate with desktop MCP clients (Claude, VSCode, Cline, Cherry Studio), add the server configuration with the appropriate command and args for your operating system.

Key features of MCP Mermaid

• Full support for all Mermaid syntax and features.
• Configurable backgroundColor and theme for styled output.
• Exports diagrams as base64, svg, mermaid code, file, svg_url, and png_url.
• Built-in Mermaid validation to help the model produce correct syntax.
• Multiple transport protocols: STDIO, SSE, and Streamable HTTP.

Use cases of MCP Mermaid

• Generate flowcharts, sequence diagrams, and other Mermaid charts via AI prompts.
• Automatically save diagrams as PNG files for AI agents using outputType: "file".
• Share diagrams through public mermaid.ink links using svg_url or png_url modes.
• Enable multi-round AI interaction to refine diagram syntax and visuals.

FAQ from MCP Mermaid

How do I install and run MCP Mermaid?

You can run it directly with npx (e.g., npx -y mcp-mermaid) or install globally with npm install -g mcp-mermaid and then use the mcp-mermaid command. Docker images are also available (susuperli/mcp-mermaid:latest).

What transport protocols are supported?

The server supports STDIO (default), SSE (Server-Sent Events), and Streamable HTTP transport. Use the -t flag to select one (e.g., mcp-mermaid -t sse).

What output formats are available?

Diagrams can be exported as base64, svg, mermaid (raw code), file (saved PNG), svg_url, or png_url. The URL modes generate publicly accessible links via mermaid.ink.

How do I configure the server for SSE or Streamable HTTP?

Use CLI options like --transport sse (or -t sse) and optionally --port (default 3033) and --endpoint (default /sse for SSE, /mcp for streamable). For global installation, run mcp-mermaid -t sse.

Can I use MCP Mermaid with desktop MCP clients?

Yes, add the server configuration to your MCP client (e.g., Claude Desktop, VSCode, Cline, Cherry Studio) using the appropriate command and args for your OS (Mac or Windows) as shown in the README.