Over the last few days, I’ve been exploring Microsoft’s new Agent Framework, a preview library that brings structured, context-aware AI capabilities directly into .NET applications.
To get familiar with its architecture and basic features, I’ve built five small “Getting Started” console samples in .NET 9, all powered by Azure OpenAI and defined via a simple .env configuration.

Each example builds upon the previous one — from a simple agent call to multi-turn conversations, function tools, approvals, and structured object outputs.

01 – SimpleAgent

The most basic example: connecting to Azure OpenAI using AzureKeyCredential, creating a simple AIAgent, and asking a question.

AIAgent agent = new AzureOpenAIClient(
    new Uri(endpoint),
    new AzureKeyCredential(key))
    .GetChatClient(deployment)
    .CreateAIAgent(instructions: "Tell me which language is most popular for development.", name: "Developer Assistant");

Console.WriteLine(await agent.RunAsync("Tell me which language is most popular for development."));

02 – ThreadAgent

Introduces multi-turn conversation threads that preserve context between user messages.

AgentThread thread = agent.GetNewThread();
Console.WriteLine(await agent.RunAsync("Tell me which language is most popular for development.", thread));
Console.WriteLine(await agent.RunAsync("Now tell me which of them to use if I want to build a web application in Microsoft ecosystem.", thread));

03 – FunctionTool

Shows how to extend the agent with function tools (custom methods) that can be invoked automatically by the AI when relevant.

[Description("Talk about dogs and provide interesting facts, tips, or stories.")]
static string TalkAboutDogs(string topic) =>
    topic.ToLower() switch
    {
        "labrador" => "Labradors are friendly and full of energy.",
        "poodle" => "Poodles are smart and hypoallergenic.",
        _ => $"Dogs are amazing companions! 🐶"
    };

var agent = new AzureOpenAIClient(new Uri(endpoint), new AzureKeyCredential(key))
    .GetChatClient(deployment)
    .CreateAIAgent("You are a funny assistant who loves dogs.",
                   tools: [AIFunctionFactory.Create(TalkAboutDogs)]);