How to add MCP Mermaid to Claude Desktop

Generate Mermaid diagrams and charts with AI dynamically, exporting to SVG, PNG, base64, file, or shareable URLs. Paste the config into ~/Library/Application Support/Claude/claude_desktop_config.json and restart Claude Desktop.

Last updated June 14, 2026 · 588★ · stdio · no auth

Claude Desktop config for MCP Mermaid

npx -y mcp-mermaid

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

Setup steps

1Open Claude Desktop → Settings → Developer → Edit Config (this opens ~/Library/Application Support/Claude/claude_desktop_config.json).
2Paste the MCP Mermaid config below under the top-level "mcpServers" key.
3Fill in any placeholder secrets (API keys, paths) in the snippet.
4Save the file, then fully quit and reopen Claude Desktop.
5Open a chat and confirm MCP Mermaid's tools appear under the 🔌 tools menu.

Before you start

Node.js with npx (or a global `npm install -g mcp-mermaid`)
Optional: Docker, to run the published susuperli/mcp-mermaid image

What MCP Mermaid can do in Claude Desktop

generate_mermaid_diagram

Generate a Mermaid diagram or chart from Mermaid syntax. Supports configuring backgroundColor and theme, and exporting to base64, svg, mermaid, file, svg_url, or png_url. Use outputType: "file" to save a PNG to disk, or the URL modes to produce shareable mermaid.ink links. Mermaid source is validated to support multi-round correction. (Tool functionality described in the README; exact tool name is not literally stated there.)

Security

Output modes svg_url and png_url upload/share diagrams via public mermaid.ink links; avoid them for sensitive content and prefer file, svg, or base64 output.

MCP Mermaid + Claude Desktop FAQ

Where is the Claude Desktop config file?

Claude Desktop reads MCP servers from ~/Library/Application Support/Claude/claude_desktop_config.json. Paste the MCP Mermaid config there under the "mcpServers" key and restart the client.

Is MCP Mermaid safe to use with Claude Desktop?

Output modes svg_url and png_url upload/share diagrams via public mermaid.ink links; avoid them for sensitive content and prefer file, svg, or base64 output.

Which output formats are supported?

base64, svg, mermaid, file, and the remote-friendly svg_url and png_url. Use outputType: "file" to automatically save PNG diagrams to disk.

What transports does it support?

stdio by default, plus SSE (default endpoint /sse, port 3033) and Streamable HTTP (default endpoint /mcp, port 1122). Transport, port, and endpoint are configurable via the -t, -p, and -e CLI options.

Can I run it with Docker?

Yes. Pull susuperli/mcp-mermaid:latest and run it with --transport sse (default) or --transport streamable --port 1122.

View repo Full MCP Mermaid page