MCP Now
Unity3d Game Engine

Unity3d Game Engine

by CoderGamester
GitHub

An MCP server that enables LLMs to interact with Unity3d Game Engine, supporting access to a variety of the Unit's Editor engine tools (e.g. Console Logs, Test Runner logs, Editor functions, hierarchy state, etc) and executing them as MCP tools or gather them as resources.

unity
server
editor
package
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MCP Unity

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Unity MCP server 
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MCP Unity is an implementation of the Model Context Protocol for Unity Editor, allowing AI assistants to interact with your Unity projects. This package provides a bridge between Unity and a Node.js server that implements the MCP protocol, enabling AI agents like Claude, Windsurf, and Cursor to execute operations within the Unity Editor.

Features

This MCP currently provides the following tools:

  • execute_menu_item: Executes Unity menu items (functions tagged with the MenuItem attribute)
  • select_gameobject: Selects game objects in the Unity hierarchy by path or instance ID
  • update_component: Updates component fields on a GameObject or adds it to the GameObject if it does not contain the component
  • package_manager: Installs, removes, and updates packages in the Unity Package Manager
  • run_tests: Runs tests using the Unity Test Runner
  • notify_message: Displays messages in the Unity Editor

This MCP currently provides the following resources:

  • get_menu_items: Retrieves a list of all available menu items in the Unity Editor to facilitate execute_menu_item tool
  • get_hierarchy: Retrieves a list of all game objects in the Unity hierarchy
  • get_gameobject: Retrieves detailed information about a specific GameObject by instance ID, including all GameObject components with it's serialized properties and fields
  • get_console_logs: Retrieves a list of all logs from the Unity console
  • get_packages: Retrieves information about installed and available packages from the Unity Package Manager
  • get_assets: Retrieves information about assets in the Unity Asset Database
  • get_tests: Retrieves information about tests in the Unity Test Runner

Requirements

Installation

Installing this MCP Unity Server is a multi-step process:

Step 1: Install Unity MCP Server package via Unity Package Manager

  1. Open the Unity Package Manager (Window > Package Manager)
  2. Click the "+" button in the top-left corner
  3. Select "Add package from git URL..."
  4. Enter: https://github.com/CoderGamester/mcp-unity.git
  5. Click "Add"

package manager

Step 2: Install Node.js

To run MCP Unity server, you'll need to have Node.js 18 or later installed on your computer:

Windows
  1. Visit the Node.js download page
  2. Download the Windows Installer (.msi) for the LTS version (recommended)
  3. Run the installer and follow the installation wizard
  4. Verify the installation by opening PowerShell and running: 
    1node --version
macOS
  1. Visit the Node.js download page
  2. Download the macOS Installer (.pkg) for the LTS version (recommended)
  3. Run the installer and follow the installation wizard
  4. Alternatively, if you have Homebrew installed, you can run: 
    1brew install node@18
  5. Verify the installation by opening Terminal and running: 
    1node --version

Step 3: Configure AI LLM Client

Option 1: Configure using Unity Editor
  1. Open the Unity Editor
  2. Navigate to Tools > MCP Unity > Server Window
  3. Click on the "Configure" button for your AI LLM client as shown in the image below

image

  1. Confirm the configuration installation with the given popup

image

Option 2: Configure via Smithery

To install MCP Unity via Smithery:

Currently not available
Option 3: Configure Manually

Open the MCP configuration file of your AI client (e.g. claude_desktop_config.json in Claude Desktop) and copy the following text:

Replace ABSOLUTE/PATH/TO with the absolute path to your MCP Unity installation or just copy the text from the Unity Editor MCP Server window (Tools > MCP Unity > Server Window).

1{
2   "mcpServers": {
3   "mcp-unity": {
4      "command": "node",
5      "args": [
6         "ABSOLUTE/PATH/TO/mcp-unity/Server/build/index.js"
7      ],
8      "env": {
9         "UNITY_PORT": "8090"
10      }
11   }
12   }
13}

Start Unity Editor MCP Server

  1. Open the Unity Editor
  2. Navigate to Tools > MCP Unity > Server Window
  3. Click "Start Server" to start the WebSocket server
  4. Open Claude Desktop or your AI Coding IDE (e.g. Cursor IDE, Windsurf IDE, etc.) and start executing Unity tools

connect

Optional: Set WebSocket Port

By default, the WebSocket server runs on port 8090. You can change this port in two ways:

Option 1: Using the Unity Editor
  1. Open the Unity Editor
  2. Navigate to Tools > MCP Unity > Server Window
  3. Change the "WebSocket Port" value to your desired port number
  4. Unity will setup the system environment variable UNITY_PORT to the new port number
  5. Restart the Node.js server
  6. Click again on "Start Server" to reconnect the Unity Editor web socket to the Node.js MCP Server
Option 2: Using the terminal
  1. Set the UNITY_PORT environment variable in the terminal
    • Powershell
    1$env:UNITY_PORT = "8090"
    • Command Prompt/Terminal
    1set UNITY_PORT=8090
  2. Restart the Node.js server
  3. Click again on "Start Server" to reconnect the Unity Editor web socket to the Node.js MCP Server

Debugging the Server

Building the Node.js Server

The MCP Unity server is built using Node.js . It requires to compile the TypeScript code to JavaScript in the build directory. To build the server, open a terminal and:

  1. Navigate to the Server directory:

    1cd ABSOLUTE/PATH/TO/mcp-unity/Server

  2. Install dependencies:

    1npm install

  3. Build the server:

    1npm run build

  4. Run the server:

    1node build/index.js
Debugging with MCP Inspector

Debug the server with @modelcontextprotocol/inspector:

  • Powershell
1$env:UNITY_PORT=8090; npx @modelcontextprotocol/inspector node Server/build/index.js
  • Command Prompt/Terminal
1set UNITY_PORT=8090 && npx @modelcontextprotocol/inspector node Server/build/index.js

Don't forget to shutdown the server with Ctrl + C before closing the terminal or debugging it with the MCP Inspector.

Enable Console Logs
  1. Enable logging on your terminal or into a log.txt file:
    • Powershell
    1$env:LOGGING = "true"
2$env:LOGGING_FILE = "true"
    • Command Prompt/Terminal
    1set LOGGING=true
2set LOGGING_FILE=true

Troubleshooting

Connection Issues
  • Ensure the WebSocket server is running (check the Server Window in Unity)
  • Check if there are any firewall restrictions blocking the connection
  • Make sure the port number is correct (default is 8080)
  • Change the port number in the Unity Editor MCP Server window. (Tools > MCP Unity > Server Window)
Server Not Starting
  • Check the Unity Console for error messages
  • Ensure Node.js is properly installed and accessible in your PATH
  • Verify that all dependencies are installed in the Server directory
Menu Items Not Executing
  • Ensure the menu item path is correct (case-sensitive)
  • Check if the menu item requires confirmation
  • Verify that the menu item is available in the current context

Support & Feedback

If you have any questions or need support, please open an issue on this repository.

Alternative you can reach out on

Contributing

Contributions are welcome! Please feel free to submit a Pull Request or open an Issue with your request.

Commit your changes following the Conventional Commits format.

License

This project is under MIT License