mermaid

This MCP server provides real-time and batch validation for Mermaid diagrams. It exposes a set of tools that let you validate single diagrams, perform real-time validation during editing, and run batch validation across multiple diagrams. You can validate a single diagram with validate_mermaid to get a quick pass/fail result along with an inferred diagram type and error details. For live editing scenarios, use mermaid_realtime_validate to receive enhanced feedback including the type of change and line number. When you need to process multiple diagrams at once, batch them with validate_mermaid_batch and inspect a concise summary plus individual results. You can also query server information and the supported diagram types via get_mermaid_info to monitor capabilities and performance metrics.

Prerequisites:

• Node.js v18.x or newer
• npm (included with Node.js)
• Git

Install and run the Mermaid MCP Server locally:

1. Clone the repository:

git clone <repository-url>
cd mermaid-mcp-server

2. Install dependencies:

npm install

3. Start the server (development mode):

npm run dev

4. If you want to run via MCP client configuration, ensure your client points to the server.js entry, e.g.:

• Command: node
• Args: ["/path/to/mermaid-mcp-server/server.js"]
• Environment: set appropriate variables as needed (see below)

Optional environment variables you may configure:

• DEBUG: Enable verbose debug logs (e.g. mermaid-mcp-server:*).
• NODE_ENV: Set to development or production.
• MEMORY_LIMIT: Limit the memory usage (in MB).
• PERFORMANCE_MONITORING: Enable performance metrics collection.

Tips and notes:

• The server is designed for lightweight, real-time Mermaid diagram validation with minimal memory footprint.
• Supported diagram types include Flowcharts, Sequence Diagrams, Class Diagrams, State Diagrams, ER Diagrams, Gantt, Mind Maps, Timelines, C4 Architecture, Sankey, Block, Architecture, and more.
• Use get_mermaid_info to inspect server status, uptime, and supported diagram types.
• For debugging startup issues, verify Node.js version (>= 18) and ensure dependencies are installed.
• If memory usage spikes, consider batch validation or restarting the server as needed and adjust MEMORY_LIMIT.
• Environment variables in MCP config can be tuned per deployment to balance logging, debugging, and performance.