Getting Started with Unreal Engine 5

The unreal engine 5 SDK is a plugin that allows automated log collection, performance testing and offers a framework to increase the AI agent’s capabilities, by writing custom functions called flayer functions.

The heart of the SDK is the NunuSubsystem a GameInstanceSubsystem that handles the lifecycle and connection management of all nunu components.

The SDK works with Unreal Engine 4.27 and newer versions, but we recommend using Unreal Engine 5 for access to the latest features and improvements. Be aware that some features aren’t fully supported in older versions.

Quick Start Guide

Here’s a quick guide on how to install and test the basic nunu sdk integration:

Installation

First, let’s get the SDK up and running in your project:

Download the latest SDK release from the nunu hub.
Unzip the package
Copy the NunuSDK folder into your project’s Plugins directory and add NunuSDK to your project Build.cs file as a dependency.

The nunu plugin is structured as a standard unreal engine plugin. It contains the following 2 modules:

NunuSDK: The core runtime module that contains the NunuSubsystem and the core functionality of the SDK.
NunuSDKEditor: The editor module that contains blueprint utilities and editor tools for flayer function development.

Initial Setup

Once you’ve placed the files:

Wait for your IDE to detect and load the new modules
Rebuild your project
Launch the Unreal Engine editor

Configuration

Navigate to Edit > Project Settings > Plugins > NunuSDK to set up your environment:

Configure your preferred Nunu console hotkey (default: F7)

Nunu SDK Settings

Pro tip: Choose a key that won’t conflict with your existing game or debug controls

Your First Connection

We are going to test the integration using the flayer debugger. The flayer debugger is a tool that allows you to test and debug your flayer functions.

More info on how to get a connection string can be found in the Flayer Debugger section

Let’s establish communication with the SDK:

Launch your game in editor play mode
Press your configured hotkey to open the Nunu console
Obtain a flayer debugger connection string from Nexus
Paste the connection string into the console
Press Enter or click the connect button

Success Indicator: You’ll see a “connected” message replace your connection string.

Nunu Console

The console window isn’t available in Unreal Engine 4. Instead, you can connect using the built-in command: NunuConnect "your_connection_string" Make sure to put your connection string in double quotes. This method also works in Unreal Engine 5 as an alternative to the console.

Verification

Now that you’re connected, let’s verify the integration:

Click on fetch functions to get all available functions from the SDK
Run the game_state command
You should receive basic game state information in response

Creating Your First Flayer Function

Now that we have our SDK running, let’s explore both approaches to creating custom functions.

Option 1: C++ Implementation

Flayer functions are the core part of expanding the AI agent’s capabilities. For a more in-depth guide on how to write flayer functions in unreal engine, check out the Flayer Functions Libraries section.

To create a flayer function in C++, we’ll build a custom FlayerFunctionLibrary class. Unlike standard Blueprint function libraries, this class provides:

Access to WorldContext
A Tick function

The NunuSubsystem handles all instance management and registration automatically.

To create a flayer function, we need to add a new UFUNCTION inside our FlayerFunctionLibrary class. Here are the key requirements:

Must return a single primitive type (int, float, string, etc.)
Can receive any primitive type as arguments
Must have PacketLogger as the last argument (used for sending messages to the AI agent)

Let’s create a simple comparison function:


#pragma once
#include "Flayer/FlayerFunctionLibrary.h"
#include "Network/PacketLogger.h"
#include "MyFirstFlayerFunctions.generated.h"
 
UCLASS()
class UMyFirstFlayerFunctions : public UFlayerFunctionLibrary
{
	GENERATED_BODY()
public:
 
	UMyFirstFlayerFunctions()
	{
		REGISTER_FLAYER_FUNCTION_SHORT(CompareTwoNumbers, "compare_two_numbers", "Compares two numbers and logs the result");
	}
 
	UFUNCTION()
	int CompareTwoNumbers(int A, int B, UPacketLogger* Logger)
	{
		if (A > B)
		{
			Logger->LogToAI(TEXT("A is greater than B"));
			return 1;
		}
 
		if (A < B)
		{
			Logger->LogToAI(TEXT("A is less than B"));
			return -1;
		}
 
 
		Logger->LogToAI(TEXT("A is equal to B"));
		return 0;
	}
};

This function demonstrates several key concepts:

Function registration using REGISTER_FLAYER_FUNCTION_SHORT macro
Unique and descriptive packet name (“compare_two_numbers”)
Clear function description for the flayer debugger
Proper use of the PacketLogger for AI communication
Registration in the constructor for proper exposure to the Eldritchlink network client

After recompiling and reconnecting to the flayer debugger, your new function will appear in the available functions list, ready for testing.

Option 2: Blueprint Implementation

For those who prefer visual scripting, let’s create a flayer function using Blueprints. We’ll build a simple string reversal function.

Create Your Blueprint Class

Right-click in content browser → Blueprint Class
Search for FlayerFunctionLibrary and select
Name the new blueprint class MyFirstFlayerBlueprintFunctionLibrary.

Add Your Function

The key requirements remain the same as C++:

Must return a single primitive type (int, float, string, etc.)
Can receive any primitive type as arguments
Must include PacketLogger as the last argument (used for sending messages to the AI agent).

reverse string function

Register the function in the Library class

In the EventGraph search for Event On Register Blueprint Flayer Functions and add the event node to the graph.
Add a Register Blueprint Flayer Function node and connect the execution pins.
To the Function Name pin, connect a Get Flayer Function Name node and in the dropdown select the function you created.
Create FlayerFunctionMeta for the metadata pin to set function name and description

This is what it should look like: flayer blueprint registration

Register the library class in the nunu subsystem

To register the library class in the NunuSubsystem, we need to add it to the additional flayer function libraries in the project settings.

Go to the Edit > Project Settings menu. Scroll down to the Plugins > NunuSDK section. And add the MyFirstFlayerBlueprintFunctionLibrary class to the Additional Library Components array.

adding additional libraries