draw-io-gomcp 中文

A local, zero-dependency Draw.io (diagrams.net) MCP server written in Go.

draw-io-gomcp is a Model Context Protocol (MCP) server that exposes draw.io diagramming capabilities to any MCP-compatible AI client. It is implemented in pure Go as a local CLI application that communicates over the stdio transport, so it runs on Windows, macOS, and Linux with no runtime dependencies beyond a single binary.

This project is a Go port of next-ai-draw-io, converted from its v0.5 release. It keeps the same clean tool surface but is rebuilt from the ground up in Go and will evolve independently going forward.

Why draw-io-gomcp?

Related MCP server: dgmo-mcp

Features

• MCP stdio server — speaks the MCP protocol over standard input/output, so it plugs into any client.

• Diagram generation — let your AI assistant create draw.io diagrams from natural language.

• Live preview — results can be previewed immediately, and you can refine the diagram with follow-up edits.

• Cross-platform — prebuilt binaries for Windows, macOS (Intel & Apple Silicon), and Linux.

• Minimal configuration — a tiny config is enough to get started; no complex setup.

Installation

Download the prebuilt binary for your platform from the Releases page, or build it yourself:

# Build from source (requires Go 1.22+)
git clone https://github.com/aosfather/draw-io-gomcp.git
cd draw-io-gomcp
go build -o draw-io-gomcp ./cmd/server

# Run
./draw-io-gomcp

Configuration

draw-io-gomcp needs only a small amount of configuration to work. The recommended way is to register it as an MCP server in your client's config file and point command at the binary.

Example: WorkBuddy

Add the following entry to your WorkBuddy MCP configuration (~/.workbuddy/mcp.json):

{
  "mcpServers": {
    "draw-io": {
      "command": "/absolute/path/to/draw-io-gomcp",
      "args": [],
      "env": {}
    }
  }
}

Replace /absolute/path/to/draw-io-gomcp with the actual path to the binary on your machine.

Example: Other MCP clients (Claude Desktop, Cursor, etc.)

The same shape applies to any client that supports the stdio transport:

{
  "mcpServers": {
    "draw-io": {
      "command": "/absolute/path/to/draw-io-gomcp"
    }
  }
}

After adding the configuration, trust / enable the server in your client, then start a new session. The draw.io tools will appear automatically.

Usage

Once connected, simply ask your AI assistant to draw something, for example:

• "Draw a sequence diagram of a login flow."

• "Create a class diagram for a blog system."

• "Make an architecture diagram showing the frontend, API, and database."

The assistant generates the diagram, and you can preview it live and ask for refinements ("make the database box red", "add an error path", etc.).

Capability routing

Tool descriptions and all four MCP behaviour hints are generated from internal/capabilities/capabilities.json, which also drives the registry index and the bundled skill's routing table. Long-form drawing rules are split into nine guide sections and loaded on demand with get_guide(sections=[...]); start_session returns a next_step instead of injecting the whole guide. get_drawing_guide remains as a legacy full-text alias.

go run ./cmd/capgen -check                                            # lint the catalogue
go run ./cmd/capgen -out build/capabilities.index.json                 # registry / router index
go run ./cmd/capgen -skill skills/draw-io-gomcp/references/routing-index.md

go test ./... fails if the generated routing table or the skill's frontmatter description drifts from the catalogue, so regenerate both before committing.

Restart the MCP session after changing the catalogue: tools/list is fetched once per connection and cached.

Bundled skill package

skills/draw-io-gomcp/ is a self-contained Agent Skill package (frontmatter, installer and references) that lives in this repository. Releasing the server no longer requires tracking down a separate copy of the docs. To publish, zip that directory with SKILL.md at the archive root; the PUBLISH.md inside it has the full checklist.

How it works

┌──────────────┐   stdio (MCP)   ┌────────────────────┐   draw.io   ┌──────────────┐
│ AI Client    │ ───────────────▶│ draw-io-gomcp     │ ───────────▶│ Diagram /    │
│ (WorkBuddy)  │ ◀───────────────│ (Go, local CLI)    │ ◀───────────│ Preview      │
└──────────────┘   JSON-RPC      └────────────────────┘   .drawio    └──────────────┘

1. The AI client sends a tool call over the MCP stdio transport.

2. draw-io-gomcp processes the request locally and produces the draw.io diagram source.

3. The result is returned to the client and rendered in the live preview for viewing and re-editing.

Porting & Roadmap

This is a Go port of next-ai-draw-io, converted from its v0.5 release. The Go version shares the same tool surface but is maintained separately and will diverge and evolve independently with improvements such as:

• Richer diagram types and templates

• A better preview / editing experience

• Additional MCP capabilities and tooling