What is mcp-server-unreal-engine GEMINI.md?

A Gemini CLI instruction file for an MCP server that lets AI assistants control an open Unreal Engine Editor session. Unreal Engine is software for making games and other real-time 3D experiences.

Helping agents build, run, and use tools for Unreal Engine actors, assets, Blueprints, properties, and console commands.

It explains the server's parts, setup requirements, and connection between the assistant and Unreal Engine.

How andrewkorot/mcp-server-unreal-engine configures Gemini CLI

Reuse

Borrowing it

Nothing to install: this file belongs to andrewkorot/mcp-server-unreal-engine. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/andrewkorot/mcp-server-unreal-engine/main/GEMINI.md

Clone the repo

git clone --depth 1 https://github.com/andrewkorot/mcp-server-unreal-engine

Made for: Gemini CLI.

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README.md

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Per session 1,010 This file is loaded in full into every session.

When invoked 1,010 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01010	$0.01010
Opus 5	$0.00505	$0.00505
Sonnet 5	$0.00202	$0.00202
Haiku 4.5	$0.00101	$0.00101

Measured 8d ago against content hash a92161d9fcee, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

mcp-server-unreal-engine GEMINI.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to unreal-mcp GEMINI.md — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

GEMINI.md · 99 lines

How it starts

The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Unreal Engine MCP Server

Project Overview

The Unreal Engine MCP Server (unreal-engine-mcp-server) is a comprehensive Model Context Protocol (MCP) server that enables AI assistants to control Unreal Engine via a native automation bridge. It facilitates bidirectional communication between an AI agent (running via MCP) and an active Unreal Engine Editor session.

Architecture

The system is composed of three main components:

MCP Server (Node.js/TypeScript):
- Role: The core server that implements the MCP protocol, handles client requests, and orchestrates communication.
- Location: src/
- Key File: src/index.ts (Entry point), src/unreal-bridge.ts (Connection management).
- Tools: Defines MCP tools for Actor manipulation, Asset management, Blueprints, etc. (found in src/tools/).
Unreal Engine Plugin (C++):
- Role: Acts as the receiver and executor within the Unreal Engine process. It runs a WebSocket server to listen for commands from the Node.js server.
- Location: Plugins/McpAutomationBridge/
- Key Functionality: Handles execute_console_command, set_object_property, and other engine-level operations on the Game Thread.
- Communication: Listens on ws://localhost:8091 (default).

Building and Running

Prerequisites

Node.js (v18 or higher)
Unreal Engine (5.0-5.7)

Setup

Install Dependencies:
```
npm install
```
Build the Server:
```
npm run build
```
1. Unreal Plugin Installation:
- Regenerate project files and recompile your Unreal project.
- Enable the plugin in the Unreal Editor if it's not automatically enabled.
- Ensure the plugin is running (it should log "MCP Automation Bridge listening" to the Output Log).

Running the Server

To start the MCP server:

npm start

Or for development with ts-node:

npm run dev

Testing

The project includes a suite of integration tests located in the tests/ directory. These scripts act as "fake" MCP clients to verify functionality.

Read the full file on GitHub · 99 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

8d ago First seen · 99 lines · 1,010 tokens per session scan A a92161d9fcee

Subscribe to this mod's changes

mcp-server-unreal-engine GEMINI.md is an instructions file published in the GitHub repository andrewkorot/mcp-server-unreal-engine (1 stars, last pushed 5mo ago), licensed MIT. It adds 1,010 tokens to every session, about $0.0051 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to unreal-mcp GEMINI.md, differing in 0 lines, and is treated as a copy.

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mcp-server-unreal-engine: Instructions file for Gemini CLI