ZenUml/diagramly-mcp-serverless

Diagramly MCP Serverless

A Model Context Protocol (MCP) server built on Cloudflare Workers with TypeScript, supporting Streamable HTTP transport protocol.

Features

• 🚀 Serverless architecture on Cloudflare Workers
• 📡 Latest MCP Streamable HTTP transport protocol support
• 🛠️ Extensible tools framework
• 📝 Extensible prompts framework
• 🔧 TypeScript type safety
• 🌐 CORS support
• 💡 Simple project structure, easy to extend

Project Structure

diagramly-mcp-serverless/
├── src/
│   ├── index.ts              # Main Worker entry point
│   ├── tools/
│   │   ├── index.ts          # Tools registry and manager
│   │   └── mermaid-to-image.ts # Mermaid diagram to image tool
│   └── prompts/
│       ├── index.ts          # Prompts registry and manager
│       └── mermaid-flowchart.ts # Mermaid flowchart prompt
├── package.json              # Project dependencies
├── tsconfig.json             # TypeScript configuration
├── wrangler.jsonc            # Cloudflare Worker configuration
└── README.md                 # Project documentation

Quick Start

1. Local Development

npx wrangler dev

This will start the local development server, typically at http://localhost:8787

2. Deploy to Cloudflare

npx wrangler deploy

4. Type Check

npm run type-check

API Endpoints

• POST /mcp - MCP protocol communication endpoint
• GET /health - Health check endpoint
• OPTIONS /* - CORS preflight request handling

Built-in Features

Tools

Currently includes:

• mermaid-to-image: Convert Mermaid diagrams to images
  • Parameters: diagramCode (string), imageType (optional: "png" | "svg")
  • Function: Converts Mermaid diagram code to PNG or SVG images using Kroki service

Prompts

Currently includes:

• mermaid-flowchart: Convert content to Mermaid flowchart
  • Parameters: content (string)
  • Function: Generates prompts to convert user content into Mermaid flowchart diagrams

Extension Guide

Adding New Tools

1. Create a new tool file in src/tools/
2. Define your tool following the ToolDefinition interface
3. Add it to the toolRegistry in src/tools/index.ts

Example:

export const myNewTool: ToolDefinition = {
  name: "my-new-tool",
  description: "Description of what this tool does",
  inputSchema: {
    param1: z.string(),
    param2: z.number().optional()
  },
  handler: async ({ param1, param2 }) => {
    // Tool implementation logic
    return {
      content: [{
        type: "text",
        text: "Tool result"
      }]
    };
  }
};

Adding New Prompts

1. Create a new prompt file in src/prompts/
2. Define your prompt following the PromptDefinition interface
3. Add it to the promptRegistry in src/prompts/index.ts

Example:

export const myNewPrompt: PromptDefinition = {
  name: "my-new-prompt",
  config: {
    title: "My New Prompt",
    description: "Description of what this prompt does",
    argsSchema: { content: z.string() }
  },
  handler: ({ content }) => ({
    messages: [{
      role: "user",
      content: {
        type: "text",
        text: `Your prompt template here: ${content}`
      }
    }]
  })
};

Dependencies

• @modelcontextprotocol/sdk: MCP framework core
• agents: MCP agent library
• hono: Web framework for Cloudflare Workers
• zod: Data validation library
• pako: Compression library for Mermaid diagrams

License

MIT License