UnityMCP

UnityMCP is a powerful Unity Editor plugin that implements the Model Context Protocol (MCP), enabling seamless integration between Unity and AI assistants. It provides real-time editor state monitoring, remote command execution, and comprehensive logging capabilities.

Architecture

The project consists of two main components:

1. Unity Plugin (UnityMCPPlugin)

A Unity Editor plugin that provides:

• Debug window for connection status and monitoring
• WebSocket client for real-time communication
• C# code execution engine
• Comprehensive logging system
• Editor state tracking and serialization

2. MCP Server (unity-mcp-server)

A TypeScript-based MCP server that exposes Unity Editor functionality through standardized tools:

Available Tools

1. get_editor_state

   • Retrieves current Unity Editor state
   • Includes active GameObjects, selection state, play mode status
   • Provides scene hierarchy and project structure
   • Supports different output formats (Raw, scripts only, no scripts)

2. execute_editor_command

   • Executes C# code directly in the Unity Editor
   • Full access to UnityEngine and UnityEditor APIs
   • Real-time execution with comprehensive error handling
   • Command timeout protection

3. get_logs

   • Retrieves and filters Unity Editor logs
   • Supports filtering by type, content, and timestamp
   • Customizable output fields
   • Buffer management for optimal performance

Installation

Installing via Smithery

To install UnityMCP for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @Arodoid/unitymcp --client claude

Prerequisites

• Unity 2022.3 or later
• Node.js 18 or later
• npm 9 or later

Unity Plugin Setup

1. Copy the UnityMCPPlugin folder to your Unity project's Assets directory
2. Open Unity Editor
3. Access the plugin through Unity's top menu bar > UnityMCP > Debug Window

MCP Server Setup

cd unity-mcp-server
npm install
npm run build

Usage

Starting the Server

cd unity-mcp-server
node build/index.js

Connecting from Unity

1. Open your Unity project
2. Open the UnityMCP Debug Window (Window > UnityMCP > Debug Window)
3. The plugin will automatically attempt to connect to the MCP server
4. Monitor connection status and logs in the debug window

Example: Executing Commands

// Center the selected object
Selection.activeGameObject.transform.position = Vector3.zero;

// Toggle play mode
EditorApplication.isPlaying = !EditorApplication.isPlaying;

// Create a new cube
GameObject.CreatePrimitive(PrimitiveType.Cube);

Development

Building the Server

cd unity-mcp-server
npm run build

Watching for Changes

npm run watch

Inspecting MCP Communication

npm run inspector

Technical Details

Communication Protocol

• WebSocket-based communication on port 8080
• Bidirectional real-time updates
• JSON message format for all communications
• Automatic reconnection handling

Security Features

• Command execution timeout protection
• Error handling and validation
• Log buffer management
• Connection state monitoring

Error Handling

The system provides comprehensive error handling for:

• Connection issues
• Command execution failures
• Compilation errors
• Runtime exceptions
• Timeout scenarios

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0).