Unreal Engine MCP

EngineWire

EngineWire connects Claude, Cursor, VS Code or any other MCP client to a running Unreal Editor,

and let it build levels, Blueprints, UI, materials, effects and more, through a native C++ editor plugin.

🧭 One tool, over 400 capabilities · ⚙️ Native C++ editor plugin · 🌐 HTTP or stdio · 🔐 Local and token-protected by default · 🎮 Unreal Engine 5.0 – 5.8

🌐 enginewire.dev · 🛒 Fab · 🚀 Quick Start · 📖 Wiki · 📦 Releases · 💬 Discussions

📌 Which version is this? This README describes 0.6.0, the stable release: the plugin on Fab and on the Releases page, and npm unreal-engine-mcp-server (latest). The previous release, 0.5.30, exposes 23 separate tools instead of one; staying on a 0.5.30 plugin means pinning unreal-engine-mcp-server@0.5.30. See Upgrading from 0.5.x.

Contents · What it does · How it works · Quick start · The unreal tool · Configuration · Security · Engine plugins · Docker · Documentation · Development · Community

What it does

🏗️ Levels and actors

Spawn one actor or hundreds in a single call, place and attach them, find the ones sunk into the floor, and load, stream and save levels.

🧩 Blueprints and UI

Create Blueprints, variables and components, build whole event graphs in one batch, and lay out UMG widgets, with a preview image to check them.

🎨 Materials and worlds

Material graphs and instances, procedural textures, lighting, landscapes, foliage, Niagara effects and PCG graphs.

🕹️ Gameplay

Characters and animation, Gameplay Ability System, AI (Behavior Trees, State Trees, EQS), inventory, networking and Enhanced Input.

🎬 Cinematics and audio

Level Sequences, cameras, Movie Render Queue and Take Recorder; Sound Cues and MetaSounds.

🧪 Play and verify

Run Play-In-Editor with synthetic input, take screenshots the model can see, read logs, profile, run Python, and package builds.

Over 450 capabilities in all, behind a single MCP tool. The assistant finds them by searching in plain words, so nobody has to learn their names. The full list is the generated Action Reference.

A platformer level built with the MCP, in Unreal Editor 5.8. Bottom right: the plugin's status, MCP :3000 (1) , meaning the native server is running on port 3000 with one client connected.

How it works

The EngineWire plugin runs inside the editor and does all the work, on the editor's game thread, and serves MCP itself. Clients reach it in one of two ways, and both get the same single tool, unreal:

Everything listens on 127.0.0.1 and requires the project's capability token unless you change it.

Quick start

The Quick Start page walks through this with screenshots. You need Unreal Engine 5.0 to 5.8. Installing from Fab needs nothing else; building the plugin from source needs a project with C++ code (a Blueprint-only project can install from Fab or use prebuilt binaries).

1. Add the plugin

From Fab (no compiler needed). Get EngineWire on Fab. In the Epic Games Launcher, open Unreal Engine › Library › Fab Library, find EngineWire and click Install to Engine for your engine version. Open your project, enable EngineWire in Edit › Plugins and restart the editor. Fab's 0.6.0 build ships with the native server off: if the status bar reads `MCP off`, turn on Enable Native MCP Server in Edit › Project Settings › Plugins › EngineWire › Native MCP and restart once more. Fab updates follow Epic's review, so the Fab build can trail the newest release here.

From a release. Download EngineWire-plugin- .zip from the newest release on the Releases page, and copy the EngineWire folder it contains into your project:

MyGame/Plugins/EngineWire/

Or use a clone of this repository: copy plugins/EngineWire/, or reference the folder from your .uproject with "AdditionalPluginDirectories": ["C:/Path/To/Unreal_mcp/plugins"].

Open the project and let Unreal rebuild the plugin. When it's loaded, the status bar shows `MCP :3000 (0)`: the plugin serves MCP on port 3000. If you see *"Engine modules cannot be compiled at runtime"*, build the project once in Visual Studio, Rider or Xcode. More in Installation.

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

Prebuilt binaries (Blueprint-only projects, teams)

Build the plugin once on a machine with the engine and a compiler, then hand out the zip. No compiler is needed on the target machine:

node scripts/package-plugin.mjs "C:/Program Files/Epic Games/UE_5.7"

This writes build/EngineWire-v -UE5.7- .zip, where is the package.json version (currently 0.6.1-beta-a). Unzip it into YourProject/Plugins/. Binaries only work with the engine minor and platform they were built for: a 5.6 build won't load in 5.5, 5.7 or 5.8.

2. Connect your client

Route A · Native HTTP (no Node.js)

1. Enable Native MCP Server is on by default (Edit › Project Settings › Plugins › EngineWire, port 3000); Fab's 0.6.0 build ships with it off. A project where it is off needs it on and an editor restart.

1. Read the capability token the plugin generated: /Saved/MCP/capability-token. Treat it like a password.
2. Add the server to your client and send the token in the X-MCP-Capability-Token header. Claude Code:

   claude mcp add --transport http unreal-engine http://127.0.0.1:3000/mcp --header "X-MCP-Capability-Token: <token>"

Or in a project .mcp.json (Claude Code), reading the token from an environment variable:

   {

"mcpServers": { "unreal-engine": { "type": "http", "url": "http://127.0.0.1:3000/mcp", "headers": { "X-MCP-Capability-Token": "${UNREAL_MCP_TOKEN}" } } } }

Cursor (.cursor/mcp.json) takes the same url and headers without type. VS Code, Windsurf and others: Connecting Clients.

1. Check it: when the client connects, the count in the status bar goes up.

Route B · stdio (Node.js 20.19+)

The package is a small stdio proxy in front of the same /mcp. A client connected straight to /mcp loses its session whenever the editor closes or crashes, and has to reconnect by hand. Through the proxy, every call answers NOT_CONNECTED while the editor is down, and the first call after it is back reaches it, with no reconnect. It keeps the editor's last tool list, so a session that starts before the editor still gets the real tool.

Add this to your client's MCP configuration, for example Claude Desktop's claude_desktop_config.json:

{

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

Or let the