unreal-engine-mcp-server

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
• Docker
• Documentation
• Community
• Development
• Contributing

Features

Category	Capabilities
Asset Management	Browse, import, duplicate, rename, delete assets; create materials
Actor Control	Spawn, delete, transform, physics, tags, components
Editor Control	PIE sessions, camera, viewport, screenshots, bookmarks
Level Management	Load/save levels, streaming, lighting
Animation & Physics	Animation BPs, state machines, ragdolls, vehicles, constraints
Visual Effects	Niagara particles, GPU simulations, procedural effects, debug shapes
Sequencer	Cinematics, timeline control, camera animations, keyframes
Graph Editing	Blueprint, Niagara, Material, and Behavior Tree graph manipulation
Audio	Sound cues, audio components, sound mixes, ambient sounds
System	Console commands, UBT, tests, logs, project settings, CVars

Architecture

• Native C++ Automation — All operations route through the MCP Automation Bridge plugin
• Dual Transport — Native HTTP/SSE (no bridge needed) or WebSocket via TypeScript bridge
• 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
• Capability Token Auth — Optional token-based authentication for both WS and HTTP transports
• 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

• Unreal Engine 5.0–5.8 (5.8 preview validated)

Choose your transport:

• Option A: Native MCP (recommended) — no additional dependencies
• Option B: TypeScript Bridge — requires Node.js 18+

Step 1: Install MCP Server (Option B only — skip for Native MCP)

Skip this step if using Option A: Native MCP Transport (Step 4A below).

NPX (Recommended):

npx unreal-engine-mcp-server

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.

From source (requires a project with code target)

Your project must have a code target (.sln or .xcworkspace). Blueprint-only projects cannot compile native plugins — to convert, add any class via Tools > New C++ Class in the editor.

Method 1: Copy Folder

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

Method 2: External Plugin Directory (no copy needed)

• Open Unreal Editor → Edit → Plugins
• Click Plugin Directories (bottom-left)
• In Additional Plugin Directories, add the path to Unreal_mcp/plugins/
• Restart the editor — the plugin will be picked up from the external location

This saves the path in your .uproject file so the plugin stays linked without copying.

The plugin compiles automatically when you open the project — UE detects the .uplugin + Source/ and runs UnrealBuildTool.

Video Guide:

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

⚠️ First-Time Project Open: UE may prompt "Would you like to rebuild them now?" — click Yes. If instead you see "Missing Modules — McpAutomationBridge. Engine modules cannot be compiled at runtime. Please build through your IDE." — open your project in Visual Studio (Win) or Xcode (Mac) and build from there. After that, the editor will open normally with the plugin loaded.

Pre-built (works with any project, including Blueprint-only)

Build the plugin once, then distribute the compiled binaries — no IDE or compilation needed on the target machine.

1. Build:

# macOS / Linux
./scripts/package-plugin.sh /path/to/UE_5.6

# Windows
scripts\package-plugin.bat C:\Path\To\UE_5.6

This produces a zip like McpAutomationBridge-v0.5.30-UE5.6-Mac.zip.

2. Install: unzip into YourProject/Plugins/ and open the project. That's it — no compilation step.

Note: pre-built binaries are tied to a specific UE version. A build for 5.6 won't work with 5.5, 5.7, or 5.8.

Step 3: Enable Required Plugins

Enable via Edit → Plugins, then restart the editor.

Core Plugins (Required)

Plugin	Required For
MCP Automation Bridge	All automation operations
Editor Scripting Utilities	Asset/Actor subsystem operations
Niagara	Visual effects and particle systems

Optional Plugins (Auto-enabled)

Plugin	Required For
Level Sequence Editor	manage_sequence operations
Control Rig	animation_physics operations
GeometryScripting	manage_geometry operations
Behavior Tree Editor	manage_ai Behavior Tree operations
Niagara Editor	Niagara authoring
Environment Query Editor	AI/EQS operations
Gameplay Abilities	manage_gas operations
MetaSound	manage_audio MetaSound authoring
StateTree	manage_ai State Tree operations
Smart Objects	AI smart object operations
Enhanced Input	manage_networking input mapping operations
Chaos Cloth	Cloth simulation
Interchange	Asset import/export
Data Validation	Data validation
PCG	manage_pcg graph authoring and execution
Procedural Mesh Component	Procedural geometry
OnlineSubsystem	Session/networking operations
OnlineSubsystemUtils	Session/networking operations

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

Step 4: Configure MCP Client

Option A: Native MCP Transport (Direct HTTP — no bridge needed)

The plugin includes a built-in MCP Streamable HTTP server. AI clients connect directly to the plugin over HTTP — no TypeScript bridge, no Node.js, no npm.

Enable in Unreal:

• Edit > Project Settings > Plugins > MCP Automation Bridge
• Check Enable Native MCP
• Set port (default: 3000)
• Optionally set Native MCP Instructions for project-specific guidance
• Restart the editor

Configure your MCP client to use Streamable HTTP transport at:

http://localhost:3000/mcp

Claude Code:

claude mcp add unreal-engine --transport http http://localhost:3000/mcp

Or manually in ~/.claude/settings.json or project .mcp.json:

{
  "mcpServers": {
    "unreal-engine": {
      "type": "url",
      "url": "http://localhost:3000/mcp"
    }
  }
}

Cursor (.cursor/mcp.json):

{
  "mcpServers": {
    "unreal-engine": {
      "url": "http://localhost:3000/mcp"
    }
  }
}

Verify it works:

• Status bar — look for ● MCP :3000 (2) in the bottom-right of the editor. Green dot = server running, number in parens = active sessions. Click it to open settings.
• Output Log — filter by LogMcpNativeTransport to see connections, tool calls, and session activity:

  LogMcpNativeTransport: Native MCP server started on http://localhost:3000/mcp
  LogMcpNativeTransport: MCP session initialized: ... (client: claude-code 2.1.92, active sessions: 1)
  LogMcpNativeTransport: tools/call: inspect (RequestId=...)
  LogMcpNativeTransport: tools/call completed: ... (tool=inspect, success=true)
  

Features:

• SSE streaming for real-time progress during long operations
• Multiple concurrent sessions (Cursor + Claude Code + others simultaneously)
• Dynamic tool management — core tools load by default, enable more via manage_tools
• Python execution via execute_python action (inline code or .py files)
• Capability token authentication — enable in project settings for network security

Option B: TypeScript Bridge (stdio — classic setup)

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_CONNECTION_TIMEOUT_MS=5000
MCP_REQUEST_TIMEOUT_MS=120000
ASSET_LIST_TTL_MS=10000

# Optional Prometheus metrics endpoint
# Loopback-only by default. Non-loopback metrics requires both explicit opt-in and a token.
# MCP_METRICS_PORT=9100
# MCP_METRICS_HOST=127.0.0.1
# MCP_METRICS_ALLOW_NON_LOOPBACK=false
# MCP_METRICS_TOKEN=change-me

# Custom content mount points (comma-separated)
# Plugins with CanContainContent register mount points beyond /Game/.
# MCP_ADDITIONAL_PATH_PREFIXES=/ProjectObject/,/ProjectAnimation/

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:

• Go to Edit → Project Settings → Plugins → MCP Automation Bridge
• Under Security, enable "Allow Non Loopback"
• Under Connection, set "Listen Host" to 0.0.0.0
• 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. Enable capability token authentication (Require Capability Token in project settings) to prevent unauthorized access when using LAN mode.

Available Tools

23 exposed MCP tools in broad all-tools mode. Related actions live directly on their parent tools so clients load less context without losing capabilities.

Core Tools

Tool	Description
manage_asset	Assets, Materials, Render Targets, Behavior Trees
manage_blueprint	Blueprints, SCS components, graph editing, UMG widgets, layout, bindings, animations
control_actor	Spawn, delete, transform, physics, tags
control_editor	PIE, Camera, viewport, screenshots
manage_level	Load/save, streaming, lighting
system_control	UBT, Tests, Logs, Project Settings, CVars, Python Execution
inspect	Object Introspection
manage_tools	Dynamic tool management (enable/disable at runtime)

World Building

Tool	Description
build_environment	Landscapes, foliage, procedural terrain, lighting, spline roads/rivers/fences
manage_level_structure	Levels, sublevels, World Partition, streaming, data layers, HLOD, volumes
manage_geometry	Procedural mesh creation and editing with Geometry Script
manage_pcg	PCG graph assets, subgraphs, input/sampler/filter/spawner nodes, pin connections, execution, partition grid size, and node settings

Gameplay Systems

Tool	Description
animation_physics	Animation BPs, skeletons, sockets, physics assets, cloth, vehicles, ragdolls, Control Rig, IK
manage_effect	Niagara, particles, debug shapes, GPU simulations
manage_gas	Gameplay Ability System: abilities, effects, attributes
manage_character	Character creation, movement, advanced locomotion
manage_combat	Weapons, projectiles, damage, melee combat
manage_ai	AI controllers, Behavior Trees, EQS, perception, State Trees, Smart Objects, NavMesh/pathfinding
manage_inventory	Items, equipment, loot tables, crafting
manage_interaction	Interactables, destructibles, triggers

Utility

Tool	Description
manage_audio	Audio Assets, Components, Sound Cues, MetaSounds, Attenuation
manage_sequence	Sequencer, cinematics, bindings, tracks, playback, keyframes
manage_networking	Replication, RPCs, network prediction, sessions, split-screen, LAN/voice, game framework, input mappings

### Supported Asset Types

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

Docker

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

Documentation

Document	Description
Handler Mappings	TypeScript to C++ routing
Plugin Extension	C++ plugin architecture
Testing Guide	How to run and write tests
Roadmap	Development phases

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

Resource	Description
Project Roadmap	Track development progress across 48 phases
Discussions	Ask questions, share ideas, get help
Issues	Report bugs and request features

Contributing

Contributions welcome! Please:

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

License

MIT — See LICENSE