UEMCP

Drive Unreal Engine 5 with Claude. Nothing to install inside Unreal.

UEMCP is an open source MCP server by ATDev that connects Claude (Claude Code, Claude Desktop, or any MCP client) to a live Unreal Engine 5 editor. Spawn actors, build materials, author Blueprints, manage assets, fly the viewport camera, take screenshots, and run arbitrary editor Python, all from a conversation.

Why this one is different

Most Unreal MCP servers ship a C++ plugin you have to copy into your project and compile. UEMCP speaks Unreal's built-in Python remote execution protocol instead: the same multicast discovery and TCP command channel that ships with every copy of the engine. That means:

• Zero install on the Unreal side. No plugin to build, no project files to modify, no engine version matrix to chase.
• Works with vanilla UE 5.0 through 5.6, including Epic Games Launcher builds.
• Structured results, not log scraping. Every tool runs inside an error-capturing harness in the editor and returns clean JSON, with real Python tracebacks when something fails.
• Self-healing connection. Restart the editor mid-session and the next tool call reconnects automatically.
• An escape hatch. ue_python gives Claude the full unreal module for anything the 29 dedicated tools do not cover.

Quickstart

1. Set up Unreal (one time, about 30 seconds)

1. Open your project in Unreal Editor.
2. Edit > Plugins, search for Python Editor Script Plugin, enable it, restart when prompted.
3. Edit > Project Settings, search for Python, check Enable Remote Execution.

That is the entire Unreal-side setup.

2. Add the server to Claude

With uv installed:

Claude Code

claude mcp add unreal -- uvx uemcp

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "unreal": {
      "command": "uvx",
      "args": ["uemcp"]
    }
  }
}

From a clone of this repo

uv run uemcp

3. Talk to your editor

"Spawn a point light 300 units up, make it warm orange at 8000 intensity, then screenshot the viewport."

"Find every static mesh asset with 'rock' in the name and scatter 20 of them in a rough circle around the origin."

"Create a BP_Collectible blueprint with a static mesh component and a sphere collision, set its mesh to the gold coin asset."

Tools

Conventions: project content paths look like /Game/Props/SM_Chair, engine classes like /Script/Engine.PointLight. Distances are centimeters, rotations are [roll, pitch, yaw] in degrees, colors are [r, g, b] in 0..1.

Full parameter and return documentation for every tool: docs/tools.md.

How it works

Claude (MCP client)
   |  stdio (MCP)
   v
uemcp server (this package, plain Python)
   |  UDP multicast 239.0.0.1:6766  -> discovery ping/pong
   |  TCP command channel           -> JSON commands and results
   v
Unreal Editor (built-in Python remote execution)

Each tool builds a small Python snippet, wraps it in a harness that catches exceptions, runs it in the editor, and parses a sentinel-prefixed JSON line back out of the log output. The snippet builders are pure functions, so CI compiles every one of them without needing Unreal installed.

Configuration

Everything works with defaults when the editor and server are on the same machine. Override with environment variables when needed:

uemcp --project MyGame is shorthand for UEMCP_PROJECT=MyGame.

Security notes

UEMCP executes Python inside your editor process, by design. Treat it like giving Claude the editor's Python console:

• The remote execution protocol has no authentication. Keep the defaults (localhost command channel, multicast TTL 0) unless you fully control the network.
• Tools can modify and delete project content. Use source control on your project. You should be doing that anyway.
• Review what an agent did with ue_save_all withheld if you want a manual checkpoint before anything hits disk.

Documentation

Development

git clone https://github.com/ATDev-Inc/uemcp
cd uemcp
uv sync
uv run pytest
uv run ruff check .

The test suite runs entirely without Unreal: protocol tests talk to a fake editor over real sockets, and every in-editor snippet is compile-checked.

Roadmap

• Sequencer tools (create level sequences, bind actors, render movies)
• Niagara system spawning and parameter control
• Landscape sculpting primitives
• True PIE (play-in-editor) control with input injection
• Asset thumbnails as MCP resources

PRs welcome. See CONTRIBUTING.md.

License

MIT. Copyright (c) 2026 ATDev.