ChiR24/Unreal_mcp

Unreal Engine MCP Server

A comprehensive Model Context Protocol (MCP) server that enables AI assistants to control Unreal Engine through a native C++ Automation Bridge plugin. Built with TypeScript and C++.

Table of Contents

• Features
• Getting Started
• Configuration
• Available Tools
• GraphQL API
• Docker
• Documentation
• Community
• Development
• Contributing

Features

Architecture

• Native C++ Automation — All operations route through the MCP Automation Bridge plugin
• Dynamic Type Discovery — Runtime introspection for lights, debug shapes, and sequencer tracks
• Graceful Degradation — Server starts even without an active Unreal connection
• On-Demand Connection — Retries automation handshakes with exponential backoff
• Command Safety — Blocks dangerous console commands with pattern-based validation
• Asset Caching — 10-second TTL for improved performance
• Metrics Rate Limiting — Per-IP rate limiting (60 req/min) on Prometheus endpoint
• Centralized Configuration — Unified class aliases and type definitions

Getting Started

Prerequisites

• Node.js 18+
• Unreal Engine 5.0–5.7

Step 1: Install MCP Server

Option A: NPX (Recommended)

npx unreal-engine-mcp-server

Option B: Clone & Build

git clone https://github.com/ChiR24/Unreal_mcp.git
cd Unreal_mcp
npm install
npm run build
node dist/cli.js

Step 2: Install Unreal Plugin

The MCP Automation Bridge plugin is included at Unreal_mcp/plugins/McpAutomationBridge.

Method 1: Copy Folder

Copy:  Unreal_mcp/plugins/McpAutomationBridge/
To:    YourUnrealProject/Plugins/McpAutomationBridge/

Regenerate project files after copying.

Method 2: Add in Editor

1. Open Unreal Editor → Edit → Plugins
2. Click "Add" → Browse to Unreal_mcp/plugins/
3. Select the McpAutomationBridge folder

Video Guide:

https://github.com/user-attachments/assets/d8b86ebc-4364-48c9-9781-de854bf3ef7d

⚠️ First-Time Project Open: When opening the project directly (double-click .uproject) for the first time, UE will prompt "Would you like to rebuild them now?" for missing modules. Click Yes to rebuild. After the rebuild completes, you may still see: "Plugin 'McpAutomationBridge' failed to load because module could not be loaded." This is expected — UE rebuilds successfully but doesn't reload the plugin in the same session. Simply close and reopen the project and the plugin will load correctly. Alternatively, build via Visual Studio first to avoid this.

Step 3: Enable Required Plugins

Enable via Edit → Plugins, then restart the editor.

💡 Optional plugins are auto-enabled by the MCP Automation Bridge plugin when needed.

Step 4: Configure MCP Client

Add to your Claude Desktop / Cursor config file:

Using Clone/Build:

{
  "mcpServers": {
    "unreal-engine": {
      "command": "node",
      "args": ["path/to/Unreal_mcp/dist/cli.js"],
      "env": {
        "UE_PROJECT_PATH": "C:/Path/To/YourProject",
        "MCP_AUTOMATION_PORT": "8091"
      }
    }
  }
}

Using NPX:

{
  "mcpServers": {
    "unreal-engine": {
      "command": "npx",
      "args": ["unreal-engine-mcp-server"],
      "env": {
        "UE_PROJECT_PATH": "C:/Path/To/YourProject"
      }
    }
  }
}

Configuration

Environment Variables

# Required
UE_PROJECT_PATH="C:/Path/To/YourProject"

# Automation Bridge
MCP_AUTOMATION_HOST=127.0.0.1
MCP_AUTOMATION_PORT=8091

# LAN Access (optional)
# SECURITY: Set to true to allow binding to non-loopback addresses (e.g., 0.0.0.0)
# Only enable if you understand the security implications.
MCP_AUTOMATION_ALLOW_NON_LOOPBACK=false

# Logging
LOG_LEVEL=info  # debug | info | warn | error

# Optional
MCP_AUTOMATION_REQUEST_TIMEOUT_MS=120000
ASSET_LIST_TTL_MS=10000

LAN Access Configuration

By default, the automation bridge only binds to loopback addresses (127.0.0.1) for security. To enable access from other machines on your network:

TypeScript (MCP Server):

MCP_AUTOMATION_ALLOW_NON_LOOPBACK=true
MCP_AUTOMATION_HOST=0.0.0.0

Unreal Engine Plugin:

1. Go to Edit → Project Settings → Plugins → MCP Automation Bridge
2. Under Security, enable "Allow Non Loopback"
3. Under Connection, set "Listen Host" to 0.0.0.0
4. Restart the editor

⚠️ Security Warning: Enabling LAN access exposes the automation bridge to your local network. Only use on trusted networks with appropriate firewall rules.

Available Tools

36 MCP tools with action-based dispatch for comprehensive Unreal Engine automation.

Blueprints • Materials • Textures • Static Meshes • Skeletal Meshes • Levels • Sounds • Particles • Niagara Systems • Behavior Trees

Optional GraphQL endpoint for complex queries. Disabled by default.

GRAPHQL_ENABLED=true
GRAPHQL_PORT=4000

See .

Docker

docker build -t unreal-mcp .
docker run -it --rm -e UE_PROJECT_PATH=/project unreal-mcp

Documentation

Development

npm run build       # Build TypeScript
npm run lint        # Run ESLint
npm run test:unit   # Run unit tests
npm run test:all    # Run all tests

Community

Contributing

Contributions welcome! Please:

• Include reproduction steps for bugs
• Keep PRs focused and small
• Follow existing code style

License

MIT — See