@createlex/createlexgenai

CLI tool for integrating AI-powered tools with Unreal Engine. Works as an MCP server for AI CLI tools (Claude Code, Codex CLI, Gemini CLI, etc.) or as a standalone command-line interface.

71+ tools for spawning actors, creating Blueprints, managing materials, UI widgets, physics, project architecture, and more — all without requiring a custom UE plugin.

CreateLex offers two independent Unreal workflows: install the CreatelexGenAI editor plugin for its native tool catalog, or use this CLI standalone. Standalone mode can use UE's Web Remote Control, Python Remote Execution, and, on UE 5.8+, Epic's built-in Unreal MCP / All Toolsets endpoint without installing the CreateLex plugin.

Quick Start

# Install globally
npm install -g @createlex/createlexgenai

# Authenticate
createlex login

# Check everything is working
createlex status

# Set up your AI tool
createlex setup claude-code

Requirements

• Node.js 18+
• Unreal Engine 5.x with at least one backend enabled (see below)
• Python 3.10+ (for MCP serve mode)
• CreateLex account with active subscription

Paid SaaS Access

The npm package is an installable client for the CreateLex SaaS service. An active paid CreateLex subscription is required to execute CreateLex tools in direct CLI mode or through any supported MCP transport. The official client validates its entitlement with the CreateLex control plane and fails closed when authentication, subscription validation, or the entitlement service is unavailable.

When the server-side tool-permit rollout is enabled, every tool invocation also requires a short-lived, signed, single-use permit bound to the subscriber, device, tool name, and argument hash. Raw tool arguments are not retained in the permit audit table.

This paid gate is specific to the npm CLI and standalone Python MCP runtime. It does not change the authentication or runtime contract of the existing Native CreateLexGenAI Unreal Engine plugin.

Setup Guide (No Plugin Required)

Step 1: Install the CLI

npm install -g @createlex/createlexgenai

Or run without installing:

npx @createlex/createlexgenai --version

Step 2: Authenticate

createlex login

This opens your browser to sign in. Your token is saved to ~/.createlex/auth.json.

Verify:

createlex status

Step 3: Enable UE Built-in Backends

You need at least one of these enabled in your Unreal project. All are built into UE — no CreateLex plugin required.

Option A: Web Remote Control (Recommended)

1. Open your UE project
2. Go to Edit > Plugins
3. Enable "Remote Control API" and "Remote Control Web Interface"
4. Restart the editor
5. Go to Edit > Project Settings > Plugins > Remote Control
6. Under Remote Control Web Server, check "Auto Start Web Server"
7. Set "Remote Control HTTP Server Port" to 30010 (default)
8. Under Remote Control > Security, check "Enable Remote Python Execution"

Option B: Python Remote Execution

1. Open your UE project
2. Go to Edit > Plugins
3. Enable "Python Editor Script Plugin"
4. Restart the editor
5. Go to Edit > Project Settings > Plugins > Python
6. Under Python Remote Execution, check "Enable Remote Execution?"
7. Multicast Group Endpoint: 239.0.0.1:6766, Multicast Bind Address: 127.0.0.1 (defaults)

Option C: Unreal MCP / All Toolsets (UE 5.8+)

1. Open a UE 5.8+ project
2. Go to Edit > Plugins
3. Enable "Unreal MCP" and "All Toolsets"
4. Restart the editor
5. Go to Edit > Project Settings > Plugins > Unreal MCP
6. Enable Auto Start Server and Tool Search
7. Keep the default endpoint at http://127.0.0.1:8000/mcp, or configure matching nativeMcpPort and nativeMcpPath values in the CLI

This exposes Epic's live toolset catalog, including Semantic Search, StateTree, World Conditions, Data Registry, and toolsets Epic adds later. It is a separate catalog from the CreateLex 71+ tools.

Tip: Enable Web Remote Control and Python Remote Execution for maximum fallback reliability. Unreal MCP remains a separate Epic tool catalog.

Step 4: Verify Connection

createlex connect

Expected output (without plugin):

Plugin (TCP 9878): Not connected
Web Remote Control (HTTP 30010): Connected
Remote Execution (UDP 6766): Available
Unreal MCP / All Toolsets (HTTP 8000/mcp): Connected

Step 5: Configure Your AI Tool / IDE

Automatic Setup

# Set up a specific IDE
createlex setup <ide>

# Set up all detected IDEs at once
createlex setup --all

Supported IDEs

| IDE | Command | Config Location | |---|---|---| | Claude Code | createlex setup claude-code | CLI command (manual) | | Cursor | createlex setup cursor | ~/.cursor/mcp.json | | Windsurf | createlex setup windsurf | ~/.codeium/windsurf/mcp_config.json | | Claude Desktop | createlex setup claude-desktop | %APPDATA%/Claude/claude_desktop_config.json | | VS Code | createlex setup vscode | .vscode/settings.json | | Antigravity | createlex setup antigravity | ~/.gemini/antigravity/mcp_config.json | | Gemini CLI | createlex setup gemini-cli | ~/.gemini/settings.json | | Kiro | createlex setup kiro | ~/.kiro/settings/mcp.json | | Trae | createlex setup trae | %APPDATA%/Trae/User/mcp.json | | Augment | createlex setup augment | ~/.augment/mcp.json | | Codex | createlex setup codex | ~/.codex/config.toml |

Manual IDE Configuration

All IDEs use the same MCP server command:

npx @createlex/createlexgenai serve

Claude Code:

claude mcp add createlex-unreal -- npx @createlex/createlexgenai serve

Codex CLI (~/.codex/config.toml):

[mcp_servers.createlex-unreal]
command = "npx"
args = ["@createlex/createlexgenai", "serve"]

JSON-based IDEs (Cursor, Windsurf, Claude Desktop, etc.):

{
  "mcpServers": {
    "createlex-unreal": {
      "command": "npx",
      "args": ["@createlex/createlexgenai", "serve"]
    }
  }
}

Step 6: Start Using It

Once configured, your AI tool has access to all 71+ CreateLex Unreal Engine tools, plus Epic toolsets when Unreal MCP is enabled. Try:

• "Spawn a cube at the origin"
• "Create a Blueprint called BP_Enemy based on Character"
• "List all actors in the scene"
• "Create a medieval town"

CLI Commands

# MCP server mode (for AI CLI tools)
createlex serve                    # stdio MCP server
createlex serve --port 38080       # TCP MCP server

# Direct tool execution
createlex exec <tool> [--key value ...]
createlex exec get_all_scene_objects
createlex exec spawn_object --actor-class StaticMeshActor --location "0,0,0"
createlex exec execute_python_script --script "print('Hello from UE!')"

# List available tools
createlex tools                    # Formatted list
createlex tools --json             # JSON output
createlex tools --native           # Include Epic's live UE 5.8+ toolset catalog

# Epic UE 5.8+ Unreal MCP meta-tools
createlex exec native_mcp_list_toolsets --json
createlex exec native_mcp_describe_toolset --toolset-name <toolset>
createlex exec native_mcp_call_tool --toolset-name <toolset> --tool-name <tool> --arguments '{"key":"value"}'

# Auth
createlex login                    # Browser auth flow
createlex logout                   # Clear credentials

# Status & connection
createlex status                   # Auth + subscription + UE connection info
createlex connect                  # Test UE connection, show setup tips

# Configuration
createlex config list              # Show all settings
createlex config get unrealPort    # Get a specific value
createlex config set unrealPort 9879
createlex config reset             # Reset to defaults

# IDE setup
createlex setup                    # List supported IDEs
createlex setup claude-code        # Set up specific IDE
createlex setup --all              # Set up all detected IDEs

How Connection Fallback Works

When a tool is executed, the CLI tries backends in this order:

1. CreatelexGenAI Plugin (TCP port 9878) — Fastest, direct JSON. Used if the plugin is installed.
2. Web Remote Control (HTTP port 30010) — Translates commands to Python, executes via UE's built-in HTTP API.
3. Python Remote Execution (UDP port 6766) — Translates commands to Python, executes via UE's multicast remote execution protocol.

All 71 tools work through all backends. The ue_native_handler.py module translates every command into standalone Python that runs inside UE's interpreter.

Unreal MCP / All Toolsets (HTTP 8000/mcp) is detected separately and is intentionally not a fourth fallback tier. It exposes Epic's non-overlapping, dynamically discovered toolset catalog through native_mcp_list_toolsets, native_mcp_describe_toolset, and native_mcp_call_tool.

Available Tools (71+)

| Category | Tools | |---|---| | General | get_all_scene_objects, execute_python_script, execute_unreal_command | | Script | execute_python_script, run_automation_test | | Actors | spawn_object, delete_actor, find_actors_by_name, set_actor_transform, set_actor_property, get_actor_properties, duplicate_actor, rename_actor, set_actor_mobility, set_actor_physics | | Blueprint | create_blueprint, spawn_blueprint, compile_blueprint, add_component_to_blueprint, set_blueprint_variable, get_blueprint_details | | Blueprint Nodes | add_node, connect_nodes, add_variable, add_function, add_event, set_pin_value, get_blueprint_graph | | Materials | create_material, apply_material_to_actor, set_material_parameter, create_material_instance | | Mesh | set_static_mesh, create_procedural_mesh, merge_meshes | | Physics | simulate_physics, add_physics_constraint, set_collision_profile, add_force, set_physics_material | | UI/Widgets | create_widget, modify_widget, bind_widget_event, add_widget_animation, create_widget_component | | UI Slicing | upload_ui_image, slice_ui_image, generate_ui_from_slices | | Project | create_project_folder, get_files_in_folder, import_asset, create_level, set_level_settings | | Architecture | create_town, construct_house, construct_building, create_road, create_landscape, place_foliage, create_water_body, create_sky_atmosphere, create_lighting_scenario, create_marketplace, create_wall, create_floor | | Native UE 5.8+ MCP | native_mcp_list_toolsets, native_mcp_describe_toolset, native_mcp_call_tool |

Configuration

Settings are stored in ~/.createlex/config.json:

| Key | Default | Description | |---|---|---| | unrealPort | 9878 | CreatelexGenAI plugin TCP port | | mcpPort | 38080 | MCP TCP server port (for serve --port) | | nativeMcpPort | 8000 | UE 5.8+ built-in Unreal MCP HTTP port | | nativeMcpPath | /mcp | UE 5.8+ built-in Unreal MCP URL path | | apiBaseUrl | https://api.createlex.com/api | CreateLex API endpoint | | webBaseUrl | https://createlex.com | CreateLex web app URL | | debug | false | Enable debug logging |

Troubleshooting

"No backends connected to Unreal Engine"

• Make sure UE is running with your project open
• Enable Web Remote Control, Python Remote Execution, or UE 5.8+ Unreal MCP (see Step 3)
• Run createlex connect for detailed diagnostics

"Authentication: Not logged in"

createlex login

"Subscription: Inactive"

• Visit createlex.com to check your subscription status
• Run createlex status to see the specific error

Web Remote Control not responding

• Check Edit > Project Settings > Plugins > Remote Control in UE
• Ensure "Enable Remote Control Web Server" is checked
• Verify port 30010 is not blocked by firewall

Python Remote Execution not available

• Check Edit > Project Settings > Plugins > Python in UE
• Ensure "Enable Remote Execution" is checked
• Verify UDP port 6766 is not blocked

Unreal MCP / All Toolsets not available

• UE 5.8 or newer is required
• Enable "Unreal MCP" and "All Toolsets" under Edit > Plugins, then restart UE
• Enable Auto Start Server and Tool Search under Project Settings > Plugins > Unreal MCP
• Confirm the UE endpoint matches nativeMcpPort and nativeMcpPath
• The CLI can only observe whether the endpoint is reachable; it cannot distinguish missing, disabled, or not-yet-started plugins

License

Copyright CreateLex LLC. All rights reserved. This package is proprietary, not open source, and requires an active paid CreateLex subscription. See LICENSE for the applicable terms.