Union

Union MCP Server lets you run Unity projects with a Model Context Protocol client, enabling multimodal vision, powerful search, and integrated tooling directly within Unity. It provides a streamlined way to connect your editor, project, and AI agent for faster iteration and deeper automation.

How to use

To use the Union MCP Server, run the Unity MCP runner through your MCP client. This starts the server and connects Unity to your agent so you can perform actions like inspecting assets, opening scenes, searching the project, executing code, and more.

How to install

Prerequisites you need before beginning:

• Install Node.js (the MCP runner runs on Node).
• Have a Unity editor installation available where your project lives.

Create or edit your MCP configuration file to define the Unity MCP server. Use the following configuration snippet as your mcp.json entry. This will automatically install the is.nurture.mcp package into your Unity project when you run the runner.

{
  "mcpServers": {
    "unity": {
      "command": "npx",
      "args": ["-y", "@nurture-tech/unity-mcp-runner", "-unityPath", "<path to unity editor>", "-projectPath", "<path to unity project>"]
    }
  }
}

Additional sections

Tools and capabilities are organized into categories such as Assets, Prefabs, Scenes, Scripting, and Search. You can retrieve asset contents, copy or import assets, open and edit scenes or prefabs, inspect game objects, test active scenes, create or edit scripts, execute code, and perform comprehensive searches across assets and scene objects. Vision tools can focus on a game object and capture screenshots, while editor state tools let you query the current editor state or selection.

Configuration notes and usage tips help you tailor the integration to your project. For best results, launch Unity through your MCP integration rather than directly from the Unity Hub, and consider per-project MCP settings to switch between Unity projects seamlessly. When extending with your own tools, define a static class with the appropriate MCP annotations and restart Unity so the agent recognizes the new tools.

Security and troubleshooting

If you encounter startup issues or tool edge cases, verify that the Unity editor path and project path in your mcp.json are correct, and ensure the MCP runner has the necessary permissions to launch Unity. If a tool returns ambiguous errors, re validate the tool’s parameters and, if needed, restart the Unity editor to pick up new tools.

Usage notes and tips

Important usage notes include avoiding the -logFile argument for Unity when using the MCP server, and ensuring the Unity editor is visible on screen when using vision-related tools like screenshot. You can extend the toolset by adding project-specific tools using the MCP SDK annotations and restarting Unity to register the new tools.

Available tools

get_asset_contents

Get the full contents of an asset or sub-asset.

copy_asset

Copy an asset to a new path.

import_asset

Import an asset from the filesystem into Unity.

get_asset_importer

Get the importer settings for an asset.

open_prefab

Open a Unity prefab in isolation mode so that it can be edited.

open_scene

Open a scene.

close_scene

Close an open scene.

save_scene

Save the current scene. If the scene is not dirty, this will do nothing.

get_game_object

Get the details of a game object in a loaded scene or prefab by its hierarchy path.

test_active_scene

Test the active scene by entering play mode and running for a given number of seconds.

create_script

Create or replace a C# code file at the given path. This also checks to make sure the script compiles.

execute_code

Execute code inside the Unity editor.

get_type_info

Get public fields and methods on a Unity fully qualified type name, including the assembly.

search

Search project assets and scene objects.

get_state

Get the state of the Unity Editor.

get_selection

Get the objects the user has currently selected in the editor.

focus_game_object

Focus on a game object in the scene view.

screenshot

Retrieve a preview of what is focused in the scene view.