unreal-engine-mcp-server

v0.5.30

Published

9 days ago

A comprehensive Model Context Protocol (MCP) server that enables AI assistants to control Unreal Engine via native automation bridge. Built with TypeScript and designed for game development automation.

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chir24

mcp modelcontextprotocol unreal unreal-engine ue5 remote-control automation game-development

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++.

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.

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

| 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.

| 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) |

| 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 |

| 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 |

| 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 |

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