# MCP Automation Bridge

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
[![Unreal Engine](https://img.shields.io/badge/Unreal%20Engine-5.0--5.8-orange)](https://www.unrealengine.com/)
[![GitHub](https://img.shields.io/badge/GitHub-ChiR24/Unreal__mcp-blueviolet?logo=github)](https://github.com/ChiR24/Unreal_mcp)

An Unreal Engine editor plugin that enables AI assistants (Claude, Cursor, Windsurf, etc.) to control Unreal Engine through the Model Context Protocol (MCP).

---

## 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 |
| **Sequencer** | Cinematics, timeline control, camera animations |
| **Graph Editing** | Blueprint, Niagara, Material, Behavior Tree graphs |
| **Audio** | Sound cues, audio components, MetaSounds |
| **System** | Console commands, UBT, tests, logs, project settings, Python execution |

Automation coverage spans the plugin's consolidated MCP tool surface.

---

## Requirements

- **Unreal Engine**: 5.0 - 5.8 (5.8 preview validated)
- **Platforms**: Win64, Mac, Linux
- **Node.js**: 18+ (only for TypeScript bridge transport — not needed for Native MCP)

---

## Installation

### Method 1: Copy to Project

1. Copy the `McpAutomationBridge` folder to your project's `Plugins/` directory:
   ```
   YourProject/Plugins/McpAutomationBridge/
   ```

2. Regenerate project files:
   - Right-click `.uproject` → "Generate Visual Studio project files"
   - Or run: `GenerateProjectFiles.bat`

3. Open your project in Unreal Editor

4. Enable required plugins in **Edit → Plugins**:

<details>
<summary><b>Core Plugins (Required)</b></summary>

   - ✅ MCP Automation Bridge
   - ✅ Python Editor Script Plugin
   - ✅ Editor Scripting Utilities
   - ✅ Niagara
   - ✅ Gameplay Abilities (for `manage_gas`)
   - ✅ Smart Objects (for AI smart objects)

</details>

<details>
<summary><b>Optional Plugins (Auto-enabled)</b></summary>

   - ✅ Level Sequence Editor (for `manage_sequence`)
   - ✅ Control Rig (for `animation_physics`)
   - ✅ RigVM (for Control Rig and graph authoring support)
   - ✅ GeometryScripting (for `manage_geometry`)
   - ✅ GeometryProcessing (for geometry processing support)
   - ✅ Behavior Tree Editor (for `manage_ai` Behavior Trees)
   - ✅ Niagara Editor (for Niagara authoring)
   - ✅ MetaSound (for `manage_audio` MetaSounds)
   - ✅ StateTree (for `manage_ai` State Trees)
   - ✅ Enhanced Input (for `manage_networking` input mappings)
   - ✅ Environment Query Editor (for AI/EQS)
   - ✅ Chaos Cloth (for cloth simulation)
   - ✅ Interchange (for asset import/export)
   - ✅ Data Validation (for data validation)
   - ✅ PCG (for `manage_pcg` graph authoring and execution when enabled for the build)
   - ✅ Procedural Mesh Component (for procedural geometry)
   - ✅ OnlineSubsystem (for sessions/networking)
   - ✅ OnlineSubsystemUtils (for sessions/networking)

</details>

   > 💡 Optional plugins are auto-enabled by the MCP Automation Bridge plugin. PCG support is compiled for source projects when the project explicitly enables PCG; versioned release packages for UE 5.2+ include it.

5. Restart the editor

### Method 2: Add in Editor

1. Open Unreal Editor → **Edit → Plugins**
2. Click **"Add"** button
3. Browse to and select the `McpAutomationBridge` folder
4. Enable the plugin and restart

---

## Quick Start

### Option A: Native MCP Transport (no Node.js needed)

The plugin includes a built-in MCP Streamable HTTP server. AI clients connect directly — no TypeScript bridge required.

1. Enable in **Edit → Project Settings → Plugins → MCP Automation Bridge**:
   - Check **Enable Native MCP**
   - Set port (default: `3000`)
2. Restart the editor
3. Configure your AI client for Streamable HTTP at `http://localhost:3000/mcp`

**Claude Code:**
```bash
claude mcp add unreal-engine --transport http http://localhost:3000/mcp
```

**Cursor** (`.cursor/mcp.json`):
```json
{
  "mcpServers": {
    "unreal-engine": {
      "url": "http://localhost:3000/mcp"
    }
  }
}
```

### Option B: TypeScript Bridge (classic setup)

### Step 1: Install MCP Server

```bash
# Using npx (recommended)
npx unreal-engine-mcp-server

# Or install globally
npm install -g unreal-engine-mcp-server
```

### Step 2: Configure AI Client

Add to your Claude Desktop config (`claude_desktop_config.json`):

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

### Step 3: Start Automating

1. Open your Unreal project
2. Start your AI client (Claude Desktop, Cursor, etc.)
3. The MCP server will automatically connect to the Automation Bridge

Example prompts:
- "List all assets in /Game/Characters"
- "Spawn a point light at (100, 200, 300)"
- "Create a new material called M_Glow"
- "Take a screenshot of the current viewport"

---

## Fab Technical Information

Tools & Plugins
---------------------
- **Features:** Editor automation bridge for Model Context Protocol clients. Includes native HTTP/SSE MCP transport, WebSocket bridge transport, dynamic MCP tool management, asset/actor/editor/level automation, Blueprint and graph authoring, Niagara/material/audio/AI/PCG/sequencer helpers, project/system controls, and security settings for loopback, TLS, capability tokens, and rate limits.
- **Code Modules:** `McpAutomationBridge` - Editor module.
- **Number of Blueprints:** 0.
- **Network Replicated:** No. This is an editor-only automation and MCP transport plugin; it does not add gameplay replication.
- **Supported Development Platforms:** Windows: Yes. Mac: Yes. Linux: Yes.
- **Supported Target Build Platforms:** Editor-only plugin for Win64, Mac, and Linux editor targets. It is not intended to be included in packaged game runtime builds.
- **Documentation Link:** https://github.com/ChiR24/Unreal_mcp/tree/main/plugins/McpAutomationBridge#readme
- **Example Project:** Not included. The plugin can be enabled in any Unreal Engine C++ project; see the documentation link for setup steps.
- **Important/Additional Notes:** Requires Unreal Engine 5.0-5.8. Required engine plugins are `PythonScriptPlugin`, `EditorScriptingUtilities`, `Niagara`, `GameplayAbilities`, and `SmartObjects`. Other integration references are enabled but marked optional so compatible installed engine plugins can support their matching features without becoming hard distribution dependencies. These integrations include `LevelSequenceEditor`, `NiagaraEditor`, `BehaviorTreeEditor`, `EnvironmentQueryEditor`, `ControlRig`, `RigVM`, `IKRig`, `ChaosVehiclesPlugin`, `AnimationData`, `ProceduralMeshComponent`, `Interchange`, `InterchangeOpenUSD`, `DataValidation`, `EnhancedInput`, `GeometryScripting`, `GeometryProcessing`, `ChaosCloth`, `StructUtils`, `Metasound`, `StateTree`, `MassGameplay`, `OnlineSubsystem`, `OnlineSubsystemUtils`, `Synthesis`, and `PCG`. Native MCP transport does not require Node.js. The optional TypeScript bridge transport uses the separately distributed `unreal-engine-mcp-server` Node.js package.

---

## Configuration

### Environment Variables

| Variable | Default | Description |
|----------|---------|-------------|
| `UE_PROJECT_PATH` | - | Path to your `.uproject` file |
| `MCP_AUTOMATION_HOST` | `127.0.0.1` | Bridge host address |
| `MCP_AUTOMATION_PORT` | `8091` | Bridge WebSocket port |
| `LOG_LEVEL` | `info` | Logging level (debug/info/warn/error) |

### Plugin Settings

Configure in **Edit → Project Settings → Plugins → MCP Automation Bridge**:

- **Listen Ports**: WebSocket ports (default: 8090, 8091)
- **Enable TLS**: Enable secure WebSocket connections
- **Allow Non-Loopback**: Enable LAN access (security consideration)
- **Enable Native MCP**: Enable built-in HTTP/SSE MCP server (default: off)
- **Native MCP Port**: HTTP port for native MCP transport (default: 3000)
- **Listen Host**: Bind address (default: 127.0.0.1)
- **Load All Tools on Start**: Load all 23 canonical tools at startup (default: on)
- **Native MCP Instructions**: Custom instructions for AI clients
- **Require Capability Token**: Enforce token authentication on WS and HTTP transports

---

## Security

- **Loopback-only binding** by default (127.0.0.1)
- **Capability token authentication** — enforce token on both WebSocket and Native MCP transports (enable in Project Settings)
- **TLS/SSL support** for secure connections
- **Rate limiting** support (disabled by default; configurable via Project Settings)
- **Handshake required** before automation requests
- **Command validation** blocks dangerous console commands
- **Path sanitization** — blocks directory traversal in file operations
- **Python execution security** — 1 MB code limit, symlink resolution, temp file scope guard cleanup

---

## Troubleshooting

### Plugin Failed to Load

If you see *"Plugin 'McpAutomationBridge' failed to load"* on first open:
1. Close Unreal Editor
2. Reopen the project
3. The plugin should load correctly

This is a known UE behavior when plugins are rebuilt on first load.

### Connection Refused

1. Verify the plugin is enabled in **Edit → Plugins**
2. Check port 8091 is not blocked by firewall
3. Ensure MCP server is running: `npx unreal-engine-mcp-server`

### Build Errors

The plugin uses `PCHUsageMode.NoPCHs` to prevent memory issues during compilation. If you encounter build errors:
1. Close Visual Studio
2. Delete `Intermediate/`, `Binaries/`, `Saved/` folders
3. Regenerate project files
4. Rebuild

---

## Documentation

- **Full Documentation**: [GitHub README](https://github.com/ChiR24/Unreal_mcp#readme)
- **Handler Mapping**: [docs/handler-mapping.md](https://github.com/ChiR24/Unreal_mcp/blob/main/docs/handler-mapping.md)

---

## Support

- **Issues**: [GitHub Issues](https://github.com/ChiR24/Unreal_mcp/issues)
- **Discussions**: [GitHub Discussions](https://github.com/ChiR24/Unreal_mcp/discussions)
- **Roadmap**: [Project Board](https://github.com/users/ChiR24/projects/3)

---

## License

MIT License - See [LICENSE](LICENSE) for details.

---

## Contributing

Contributions are welcome! Please:
- Include reproduction steps for bugs
- Keep PRs focused and small
- Follow existing code style