Use Antigravity with Unreal MCP

Model Context Protocol (MCP) is an open standard that lets developers build secure, two-way connections between AI assistants and data sources or tools.

Starting with Unreal Engine 5.8, integrating Unreal's MCP server with Google's Antigravity allows an AI agent in the IDE to interact directly with the Unreal Editor. This integration lets the agent seamlessly execute editor operations to streamline your game development workflow.

Set up Unreal MCP for Antigravity IDE

  1. Open the Unreal Editor, go to Edit > Plugins, and enable the Unreal MCP and All Toolsets plugins. Depending on your workflow, you can activate additional plugins.

    Unreal Editor Plugins window showing the Unreal MCP plugin enabled.
    Figure 1. Enabling Unreal MCP plugin.
    Unreal Editor Plugins window showing the All Toolsets plugin enabled.
    Figure 2. Applying All Toolsets plugin.

  2. Go to Edit > Editor Preferences, locate the General - Model Context Protocol settings, and enable Auto Start Server.

    Unreal Editor Preferences window showing the Auto Start Server option enabled.
    Figure 3. Activating Auto Start Server.

  3. To start the MCP server, restart the Unreal Editor, or in the editor console, enter the ModelContextProtocol.StartServer command.

  4. Install Antigravity IDE, and sign in with your Google Account.

  5. In the Antigravity IDE, open the Agent window, click Additional Options (the three-dot menu), and select MCP Servers > Manage MCP Servers > View raw config.

    Antigravity IDE Agent window with the three-dot options menu expanded, showing 'MCP Servers' as one of the menu items.
    Figure 4. Navigating to MCP Servers.
    Antigravity IDE menu showing the path to Manage MCP Servers.
    Figure 5. Selecting Manage MCP Servers.
    Antigravity IDE Manage MCP Servers window showing the View raw config button.
    Figure 6. Clicking View raw config button.

  6. Add this configuration to mcp_config.json, replacing [YOUR_PORT] with your Unreal Editor port:

    {
  "mcpServers":{
    "unreal-mcp":{
      "serverUrl":"http://127.0.0.1:[YOUR_PORT]/mcp"
    }
  }
}
    Antigravity IDE text editor showing the JSON configuration for the Unreal MCP server.
    Figure 7. Configuring the Unreal MCP server.

Verify setup with an example

Here's an example of using Gemini within the Antigravity IDE to add a 3D sphere to the scene.

  1. In the Antigravity IDE, open the Agent window and enter a prompt to add a 3D sphere to your scene.

    Antigravity IDE Agent window with a user prompt to add a 3D sphere.
    Figure 8. Prompting the AI agent to add a sphere.

  2. In the Unreal Editor, confirm that the sphere is in the scene.

    Unreal Editor showing a 3D sphere successfully added to the scene.
    Figure 9. Sphere added to the Unreal Editor scene.