# realvirtual.io MCP Server

Give AI agents full control over your Unity Editor — scenes, GameObjects, components, simulation, digital twins, and more.

<figure><img src="/files/aJfdg5GGwpJtRUV9TvG1" alt=""><figcaption><p>MCP Server running in Unity with 91 tools available for AI agents</p></figcaption></figure>

## Overview

The realvirtual MCP Server is a free, open-source Unity package that implements the [Model Context Protocol (MCP)](https://modelcontextprotocol.io). It lets AI agents like **Claude**, **Cursor**, or any MCP-compatible client interact with Unity in real time.

The package works with **any Unity project** — including industrial digital twins, robotics simulation, and virtual commissioning.

### How It Works

```
AI Agent (Claude Desktop / Claude Code / Cursor)
    |
    | MCP Protocol (stdio or SSE)
    v
Python MCP Server
    |
    | WebSocket (JSON, Port 18711)
    v
Unity Package (C# WebSocket server + tool registry)
```

The package runs a WebSocket server inside the Unity Editor. When an AI agent sends a tool call, the Python MCP server forwards it over WebSocket to Unity, which executes it on the main thread and returns the result.

### Key Features

* **Works with any Unity project** — Not tied to a specific framework or asset
* **Zero Python knowledge needed** — Define tools in C#, the language you're already using
* **Auto-discovery** — Tools are found via reflection, no manual registration
* **90+ built-in tools** — Scene, GameObjects, components, transforms, simulation, screenshots, and more
* **Extensible in minutes** — Add `[McpTool]` to any static method and it's available to AI agents
* **Self-contained** — Ships with embedded Python 3.12, no system Python required
* **One-click setup** — Download Python server and configure Claude from the Unity toolbar
* **Survives domain reloads** — Auto-reconnects after Unity recompiles scripts
* **Multi-instance support** — Run multiple Unity instances, each with its own MCP server

### Digital Twin Tools with realvirtual

When combined with the [realvirtual](https://realvirtual.io) framework, you get additional MCP tools purpose-built for industrial digital twins and virtual commissioning:

* **Drives** — Control motors, actuators, conveyors
* **Sensors** — Read industrial sensors
* **PLC Signals** — Read/write PLC I/O
* **Robot IK** — Inverse kinematics control

This enables AI agents to operate complete virtual factory simulations — move robots, control conveyors, read sensors, and interact with PLC programs in real time.

### Toolbar Status

The toolbar brain icon shows connection state:

| Color  | Meaning                              |
| ------ | ------------------------------------ |
| Gray   | Server stopped                       |
| Yellow | Server running, no clients connected |
| Green  | Client(s) connected                  |

The activity label next to it shows the currently executing tool call with elapsed time.

## Links

* **GitHub (Unity Package):** [github.com/game4automation/io.realvirtual.mcp](https://github.com/game4automation/io.realvirtual.mcp)
* **GitHub (Python Server):** [github.com/game4automation/realvirtual-MCP](https://github.com/game4automation/realvirtual-MCP)
* **License:** MIT

{% hint style="info" %}
This package is provided as-is. For commercial customers of [realvirtual](https://realvirtual.io), we offer professional services for digital twin development, virtual commissioning, and AI agent integration.
{% endhint %}


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# Agent Instructions: Querying This Documentation

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Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://doc.realvirtual.io/extensions/mcp-server.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.