Configuration

Configuration

MCP Client Configuration

UE-MCP runs as a standard MCP server over stdio. Configure it in your AI client by pointing at the built dist/index.js and passing your .uproject path.

Basic Configuration

{
  "mcpServers": {
    "ue-mcp": {
      "command": "node",
      "args": [
        "C:/path/to/ue-mcp/dist/index.js",
        "C:/Users/you/UnrealProjects/MyGame/MyGame.uproject"
      ]
    }
  }
}

Where to Put This

Client	Config File
Claude Code	.mcp.json in project root, or ~/.claude/ global config
Claude Desktop	claude_desktop_config.json
Cursor	mcp.json in .cursor/ or project root

Without a Project Path

You can start the server without a .uproject argument. It will run in a limited mode — you can then use project(action="set_project", projectPath="...") at runtime to attach to a project.

Project Configuration (.ue-mcp.json)

Place a .ue-mcp.json file in your UE project root (next to the .uproject) to customize behavior.

{
  "contentRoots": [
    "/Game/",
    "/MyPlugin/"
  ]
}

Options

Key	Type	Default	Description
contentRoots	string[]	["/Game/"]	Content paths to search when using asset(action="search"). Add plugin content roots here if your project uses plugins with their own assets.

Bridge Connection

The C++ plugin listens on ws://localhost:9877 (currently hardcoded). The MCP server auto-connects on startup and reconnects every 15 seconds if the connection drops.

Connection States

State	Meaning
Connected	Bridge is active, all tools available
Disconnected	Editor not running or plugin not loaded. Filesystem tools still work (INI parsing, C++ headers, asset listing)
Reconnecting	Connection lost, auto-retry in progress

Check the current state with project(action="get_status").

Plugin Deployment

On first run with a project path, the server automatically:

1. Copies plugin/ue_mcp_bridge/ → <Project>/Plugins/UE_MCP_Bridge/
2. Adds UE_MCP_Bridge to the .uproject plugins list
3. Enables PythonScriptPlugin if not already enabled (needed for execute_python escape hatch)

The plugin is editor-only and has no runtime footprint.

Plugin Dependencies

The C++ bridge plugin enables these UE plugins (adding them to .uproject if missing):

• PythonScriptPlugin — for editor(action="execute_python")
• EnhancedInput — for input action/mapping creation
• GameplayAbilities — for GAS tools
• Niagara — for VFX tools
• PCG — for procedural generation tools

Editor Lifecycle

The server can manage the editor process:

Command	Description
editor(action="start_editor")	Launch UE with the current project
editor(action="stop_editor")	Gracefully stop the editor
editor(action="restart_editor")	Stop and relaunch