BuildingChatWithOpenAi

You would be supprised, but models like Chat-GPT do not remember your conversation. Every time you send a message to it - you, actully, send entire conversation and GPT predicts what AI answer would be.

Lets try to build similar application using chains.

you would need to install LangChain meta-package or Core and OpenAI provider 

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using LangChain.Memory;
using LangChain.Providers.OpenAI.Predefined;
using static LangChain.Chains.Chain;

// we will use GPT-3.5 model, but you can use any other model
var model = new OpenAiLatestFastChatModel("your_key");

// create simple template for conversation for AI to know what piece of text it is looking at
var template =
    @"The following is a friendly conversation between a human and an AI.
{history}
Human: {input}
AI:";


// To have a conversation thar remembers previous messages we need to use memory.
// For memory to work properly we need to specify AI and Human prefixes.
// Since in our template we have "AI:" and "Human:" we need to specify them here. Pay attention to spaces after prefixes.
var conversationBufferMemory = new ConversationBufferMemory(new ChatMessageHistory());// TODO: Review { AiPrefix = "AI: ", HumanPrefix = "Human: "};

// build chain. Notice that we don't set input key here. It will be set in the loop
var chain =
    // load history. at first it will be empty, but UpdateMemory will update it every iteration
    LoadMemory(conversationBufferMemory, outputKey: "history")
    | Template(template)
    | LLM(model)
    // update memory with new request from Human and response from AI
    | UpdateMemory(conversationBufferMemory, requestKey: "input", responseKey: "text");

// run an endless loop of conversation
while (true)
{
    Console.Write("Human: ");
    var input = Console.ReadLine() ?? string.Empty;
    if (input == "exit")
        break;

    // build a new chain using previous chain but with new input every time
    var chatChain = Set(input, "input")
                    | chain;

    // get response from AI
    var res = await chatChain.RunAsync("text");


    Console.Write("AI: ");
    Console.WriteLine(res);
}

Now you can run the program and try to chat with it.

The final output will look like this: 

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Human: hello
AI: Hello! How can I assist you today?
Human: my name is Anti
AI: Hello Anti! How can I assist you today?
Human: What is my name?
AI: Your name is Anti.

As you can see, it remembers my name, so it sees previous messages.