Claude Code Integration

1 What is Claude Code?

Claude Code is Anthropic's AI coding assistant that can read, write, and execute code in your development environment. When combined with CLAUDIUS, Claude Code can directly control Unreal Engine through natural language commands.

Instead of manually writing JSON commands or clicking through menus, you can simply tell Claude what you want:

2 Setting Up the Connection

Step 2.1: Install Claude Code

If you haven't already, install Claude Code from Anthropic. It works as a VS Code extension or standalone application.

Step 2.2: Open Your Project

Open your Unreal project folder in Claude Code. Make sure CLAUDIUS is installed and the editor is running with your project loaded.

# Open your project folder in Claude Code
cd C:\Projects\MyUnrealProject
claude-code .

# Or in VS Code with Claude extension:
code C:\Projects\MyUnrealProject

Step 2.3: Copy CLAUDE.md to Project Root (Required!)

For Claude Code to understand CLAUDIUS commands, you must copy the CLAUDE.md file from the plugin folder to your project's root directory. This is the most important step!

# The CLAUDE.md file is located in the plugin folder:
YourProject/Plugins/Claudius/CLAUDE.md

# Copy it to your project root:
YourProject/CLAUDE.md

# Your project structure should look like this:
YourProject/
├── Content/
├── Config/
├── Plugins/
│   └── Claudius/
│       └── CLAUDE.md        # Original file (keep this)
├── claudius_request.json
├── claudius_response.json
└── CLAUDE.md                # ← Copy here for Claude Code!

After copying, CLAUDE.md should appear in your project root directory

Step 2.4: Test the Connection

Ask Claude to verify the setup by listing actors:

3 Understanding CLAUDE.md

The CLAUDE.md file is the key to making Claude understand CLAUDIUS. It contains:

• Command format: How to structure JSON commands
• All categories: Level, Editor, Console, Sequencer, AI, and 12 more
• Command documentation: Every command with parameters and examples
• Response format: How to interpret results

# CLAUDIUS Command Reference

## File-Based Communication
Write commands to `claudius_request.json`, responses appear in `claudius_response.json`.

## Command Format
```json
{
  "command_id": "unique_id",
  "category": "level|editor|console|...",
  "command": "command_name",
  "params": { ... }
}
```

## Level Commands

### spawn_actor
Spawns an actor in the current level.

Parameters:
- class_path (string, required): Actor class path
- location (object): {x, y, z}
- rotation (object): {pitch, yaw, roll}
- actor_label (string): Display name

Example:
```json
{
  "command_id": "spawn_1",
  "category": "level",
  "command": "spawn_actor",
  "params": {
    "class_path": "/Script/Engine.PointLight",
    "location": {"x": 0, "y": 0, "z": 300}
  }
}
```

4 Natural Language Commands

With CLAUDIUS + Claude Code, you can express commands naturally. Claude translates your intent into the correct JSON format. Here are examples across different categories:

Level Operations

// You say:
"Spawn a point light at 0, 0, 500"

// Claude writes:
{
  "command_id": "spawn_light_001",
  "category": "level",
  "command": "spawn_actor",
  "params": {
    "class_path": "/Script/Engine.PointLight",
    "location": { "x": 0, "y": 0, "z": 500 }
  }
}

Editor Operations

// "Select the actor named PlayerStart"
{ "category": "editor", "command": "select_actor", "params": { "actor_name": "PlayerStart" } }

// "Take a screenshot of the viewport"
{ "category": "viewport", "command": "take_screenshot", "params": {} }

// "Compile all blueprints"
{ "category": "build", "command": "compile_blueprints", "params": {} }

Complex Multi-Step Tasks

Claude can chain multiple commands together for complex operations:

5 Real-World Examples

Example 1: Setting Up a Character Test Scene

Example 2: Debugging AI Behavior

Example 3: Asset Pipeline

6 Tips & Best Practices

Be Specific with Positions

When specifying locations, use concrete numbers. Claude understands coordinates in Unreal's coordinate system (X forward, Y right, Z up).

Use Actor Labels

Ask Claude to name actors when spawning them. This makes it easier to reference them later.

Chain Related Commands

Don't hesitate to ask for multi-step operations. Claude will execute them in the correct order and report the results.

Check Responses

Claude will tell you if a command failed. If something doesn't work, ask Claude to check the response file for error details.