MCP 服务器

d2-mcp

Enables AI assistants to compile, validate, and explore D2 diagrams using the official D2 WASM package. It provides tools for generating SVGs with custom layouts, themes, and icons directly from D2 source code.

README

d2-mcp

MCP server for the D2 diagram language. Compile, validate, and explore D2 diagrams from any MCP-compatible AI assistant.

Uses the official @terrastruct/d2 WASM package — no CLI binary needed.

Tools

Tool	Description
`compile`	D2 source code → SVG. Supports layout engines, themes, sketch mode, dark themes, multi-board targeting, and more.
`validate`	Check D2 syntax without rendering. Returns validity status and error details.
`list_themes`	List all available D2 themes with IDs (light and dark).
`list_layouts`	List available layout engines (`dagre`, `elk`).
`list_icons`	Browse icons from icons.terrastruct.com by category (AWS, GCP, Azure, K8s, dev, essentials, tech).

Resources

Resource	Description
`d2://syntax-reference`	Complete D2 language syntax reference in markdown.

Local Development

npm install
npm run build
npm start

The server starts on port 3000 by default (override with PORT env var).

Health check: GET /health
MCP endpoint: POST /mcp (Streamable HTTP transport)

Deployment (Render)

This project includes a Dockerfile and render.yaml blueprint for one-click deployment to Render.

Push this repo to GitHub
In Render, create a new Blueprint and connect your repo
Render will auto-detect render.yaml and deploy

Or manually create a Web Service with:

Environment: Docker
Health Check Path: /health
Plan: Free

Connecting to the MCP Server

Once deployed, configure your MCP client to connect via Streamable HTTP:

{
  "mcpServers": {
    "d2": {
      "url": "https://your-service.onrender.com/mcp"
    }
  }
}

Replace the URL with your actual Render service URL (or http://localhost:3000/mcp for local).

Compile Tool Options

Parameter	Type	Description
`code`	string	D2 source code (required)
`layout`	`"dagre"` \| `"elk"`	Layout engine (default: dagre)
`sketch`	boolean	Hand-drawn sketch mode
`themeID`	integer	Theme ID (see `list_themes`)
`darkThemeID`	integer	Dark mode theme ID
`pad`	integer	Padding in pixels (default: 100)
`center`	boolean	Center SVG in viewbox
`scale`	number	Scale factor (default: fit to screen)
`target`	string	Target board for multi-board diagrams
`animateInterval`	integer	Animation interval (ms) for multi-board SVGs
`noXMLTag`	boolean	Omit XML declaration for HTML embedding