andrewginns/mermaid-mcp-server

The Mermaid MCP Server is a Python-based server designed to validate Mermaid diagrams and optionally render them as PNG images. It leverages the Mermaid CLI tool to perform these tasks, providing structured validation results that include a boolean validation status, detailed error messages, and optionally, base64-encoded PNG images of successfully rendered diagrams. This server enables LLMs to programmatically validate Mermaid diagram syntax, understand specific errors for providing helpful corrections, and receive visual confirmation of the rendered output. The server requires Node.js and the Mermaid CLI to be installed, and it uses the `uv` tool to run the server script. A Pydantic-AI MCP Client is also provided for testing purposes.

{
  "mcpServers": {
    "mermaid-validator": {
      "command": "uv",
      "args": ["run", "/path/to/mermaid_mcp_server.py"],
      "env": {
        "MCP_TRANSPORT": "stdio"
      }
    }
  }
}

{
  "mcp": {
    "servers": {
      "mermaid-validator": {
        "command": "uv",
        "args": ["run", "/path/to/mermaid_mcp_server.py"],
        "env": {
          "MCP_TRANSPORT": "stdio"
        }
      }
    }
  }
}