Examples

Unreleased Plugin

The documentation you are currently viewing is for a plugin that has not yet been released. Content may be incomplete or subject to change. Please check back once the plugin is officially available on the Fab marketplace.

This page provides complete, ready-to-use examples that demonstrate common workflows with the Runtime Local LLM plugin. Each example includes both Blueprint and C++ implementations.

Make sure you've read How to use the plugin first for an overview of the API.

Simple Chat

Create an LLM instance, load a model by name, send a message, and display the response token by token.

Blueprint

Copyable nodes.

C++

// Assuming "this" is an AActor with a UPROPERTY() URuntimeLocalLLM* LLM member
// Note: Callback functions (OnModelReady, OnToken, OnComplete, OnLLMError) must be marked as UFUNCTION() in your header file

void AMyActor::BeginPlay()
{
    Super::BeginPlay();

    LLM = URuntimeLocalLLM::CreateRuntimeLocalLLM();

    LLM->OnModelLoadedNative.AddUObject(this, &AMyActor::OnModelReady);
    LLM->OnTokenGeneratedNative.AddUObject(this, &AMyActor::OnToken);
    LLM->OnGenerationCompleteNative.AddUObject(this, &AMyActor::OnComplete);
    LLM->OnErrorNative.AddUObject(this, &AMyActor::OnLLMError);

    FLLMInferenceParams Params;
    Params.MaxTokens = 512;
    Params.Temperature = 0.7f;
    Params.SystemPrompt = TEXT("You are a helpful assistant.");

    TArray<FLLMModelMetadata> DownloadedModels = URuntimeLLMLibrary::GetAllDownloadedModelMetadata();

    // For demonstration purposes, we simply pick the first available model, swap this with your own selection logic as needed
    if (DownloadedModels.Num() > 0)
    {
        const FLLMModelMetadata& Model = DownloadedModels[0]; // Select the first available model
        FString ModelFileName = URuntimeLLMLibrary::GetModelFileName(Model);
        LLM->LoadModelByName(FName(*ModelFileName), Params);
    }
}

void AMyActor::OnModelReady(const FLLMModelMetadata& Metadata)
{
    UE_LOG(LogTemp, Log, TEXT("Model ready: %s"), *Metadata.ModelDisplayName);
    LLM->SendMessage(TEXT("Hello! Tell me a fun fact."));
}

void AMyActor::OnToken(const FString& Token)
{
    // Handle each token as it's generated (e.g. append to a string, update UI, stream to audio, etc)
    UE_LOG(LogTemp, Log, TEXT("%s"), *Token);
}

void AMyActor::OnComplete(const FString& FullResponse, float Duration, int32 Tokens, float TPS)
{
    UE_LOG(LogTemp, Log, TEXT("Done: %d tokens in %.1fs (%.1f tok/s)"), Tokens, Duration, TPS);
}

void AMyActor::OnLLMError(ELLMErrorCode ErrorCode)
{
    FText Desc = URuntimeLLMUtils::GetLLMErrorDescription(ErrorCode);
    UE_LOG(LogTemp, Error, TEXT("LLM Error: %s"), *Desc.ToString());
}

Download, Load, and Chat

Download a model from a URL at runtime, load it, and start a conversation. The download is skipped if the model already exists on disk.

Blueprint

Copyable nodes.

C++

// Assuming "this" is an AActor with a UPROPERTY() URuntimeLocalLLM* LLM member
// Note: Callback functions (OnProgress, OnModelReady, OnToken, OnComplete, OnLLMError) must be marked as UFUNCTION() in your header file

void AMyActor::BeginPlay()
{
    Super::BeginPlay();

    LLM = URuntimeLocalLLM::CreateRuntimeLocalLLM();

    LLM->OnDownloadProgressNative.AddUObject(this, &AMyActor::OnProgress);
    LLM->OnModelLoadedNative.AddUObject(this, &AMyActor::OnModelReady);
    LLM->OnTokenGeneratedNative.AddUObject(this, &AMyActor::OnToken);
    LLM->OnGenerationCompleteNative.AddUObject(this, &AMyActor::OnComplete);
    LLM->OnErrorNative.AddUObject(this, &AMyActor::OnLLMError);

    FLLMInferenceParams Params;
    Params.MaxTokens = 256;
    LLM->LoadModelFromURLSimple(
        TEXT("https://huggingface.co/bartowski/Llama-3.2-1B-Instruct-GGUF/resolve/main/Llama-3.2-1B-Instruct-Q4_K_M.gguf"), Params);
}

void AMyActor::OnProgress(float Progress, int64 BytesReceived, int64 TotalBytes)
{
    FString ProgressText = URuntimeLLMUtils::FormatDownloadProgress(BytesReceived, TotalBytes);
    UE_LOG(LogTemp, Log, TEXT("Downloading: %s"), *ProgressText);
}

void AMyActor::OnModelReady(const FLLMModelMetadata& Metadata)
{
    LLM->SendMessage(TEXT("What is the capital of France?"));
}

void AMyActor::OnToken(const FString& Token)
{
    // Handle each token as it's generated (e.g. append to a string, update UI, stream to audio, etc)
    UE_LOG(LogTemp, Log, TEXT("%s"), *Token);
}

void AMyActor::OnComplete(const FString& FullResponse, float Duration, int32 Tokens, float TPS)
{
    UE_LOG(LogTemp, Log, TEXT("Done: %d tokens in %.1fs (%.1f tok/s)"), Tokens, Duration, TPS);
}

void AMyActor::OnLLMError(ELLMErrorCode ErrorCode)
{
    FText Desc = URuntimeLLMUtils::GetLLMErrorDescription(ErrorCode);
    UE_LOG(LogTemp, Error, TEXT("LLM Error: %s"), *Desc.ToString());
}

Pre-download Models

Download models to disk without loading, useful for a settings screen or loading menu where users pick models to cache ahead of time.

Blueprint

Copyable nodes.

C++

// Assuming "this" is an AActor with a UPROPERTY() URuntimeLocalLLM* LLM member
// Note: Callback functions (OnProgress, OnDownloaded, OnLLMError) must be marked as UFUNCTION() in your header file

void AMyActor::StartPredownload()
{
    LLM = URuntimeLocalLLM::CreateRuntimeLocalLLM();

    LLM->OnDownloadProgressNative.AddUObject(this, &AMyActor::OnProgress);
    LLM->OnModelDownloadedNative.AddUObject(this, &AMyActor::OnDownloaded);
    LLM->OnErrorNative.AddUObject(this, &AMyActor::OnLLMError);

    LLM->DownloadModelFromURL(
        TEXT("https://huggingface.co/user/model/resolve/main/model-Q4_K_M.gguf"));
}

void AMyActor::OnProgress(float Progress, int64 BytesReceived, int64 TotalBytes)
{
    FString ProgressText = URuntimeLLMUtils::FormatDownloadProgress(BytesReceived, TotalBytes);
    UE_LOG(LogTemp, Log, TEXT("Downloading: %s"), *ProgressText);
}

void AMyActor::OnDownloaded(const FString& FilePath, const FLLMModelMetadata& Metadata)
{
    UE_LOG(LogTemp, Log, TEXT("Model saved to: %s"), *FilePath);
    // Model is now on disk - load it later with LoadModelByName or LoadModelFromFile
}

void AMyActor::OnLLMError(ELLMErrorCode ErrorCode)
{
    FText Desc = URuntimeLLMUtils::GetLLMErrorDescription(ErrorCode);
    UE_LOG(LogTemp, Error, TEXT("LLM Error: %s"), *Desc.ToString());
}

NPC Dialogue

A basic NPC dialogue system where the player types a message and the NPC responds. The conversation context persists between messages so the NPC remembers previous exchanges.

Blueprint

Copyable nodes.

C++

// Assuming "this" is an AActor with a UPROPERTY() URuntimeLocalLLM* LLM member
// Note: Callback functions (OnToken, OnComplete, OnLLMError) must be marked as UFUNCTION() in your header file

void ANPCActor::BeginPlay()
{
    Super::BeginPlay();

    LLM = URuntimeLocalLLM::CreateRuntimeLocalLLM();

    LLM->OnTokenGeneratedNative.AddUObject(this, &ANPCActor::OnToken);
    LLM->OnGenerationCompleteNative.AddUObject(this, &ANPCActor::OnComplete);
    LLM->OnErrorNative.AddUObject(this, &AMyActor::OnLLMError);

    FLLMInferenceParams Params;
    Params.MaxTokens = 150;
    Params.Temperature = 0.9f;
    Params.SystemPrompt = TEXT(
        "You are a grumpy blacksmith in a medieval village. "
        "Keep responses to 2-3 sentences. Stay in character.");

    // For demonstration purposes, we simply pick the first available model, swap this with your own selection logic as needed
    if (DownloadedModels.Num() > 0)
    {
        const FLLMModelMetadata& Model = DownloadedModels[0]; // Select the first available model
        FString ModelFileName = URuntimeLLMLibrary::GetModelFileName(Model);
        LLM->LoadModelByName(FName(*ModelFileName), Params);
    }
}

void ANPCActor::OnPlayerInteract(const FString& PlayerMessage)
{
    if (LLM->IsModelLoaded() && !LLM->IsGenerating())
    {
        LLM->SendMessage(PlayerMessage);
    }
}

void ANPCActor::OnToken(const FString& Token)
{
    // Stream token into dialogue widget
}

void ANPCActor::OnComplete(const FString& FullResponse, float Duration, int32 Tokens, float TPS)
{
    // Re-enable player input
}

void ANPCActor::OnPlayerLeaves()
{
    // Reset for next encounter
    LLM->ResetContext(true); // Keep system prompt
}