.NET: Declarative Agents (#2476)

* Update the declarative agent samples

* Add the Microsoft.Agents.AI.Declarative project

* Make the package non packable

* Use the RecalcEngine when creating the ChatOptions

* Ignore VSTHRD200

* Add geting started samples

* Address code review feedback

dotnet/samples/GettingStarted/DeclarativeAgents/ChatClient/Program.cs

@@ -0,0 +1,55 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample shows how to load an AI agent from a YAML file and process a prompt using Azure OpenAI as the backend.
+
+using System.ComponentModel;
+using Azure.AI.OpenAI;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using Microsoft.Extensions.AI;
+
+var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT") ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
+var deploymentName = Environment.GetEnvironmentVariable("AZURE_OPENAI_DEPLOYMENT_NAME") ?? "gpt-4o-mini";
+
+// Create the chat client
+IChatClient chatClient = new AzureOpenAIClient(
+    new Uri(endpoint),
+    new AzureCliCredential())
+     .GetChatClient(deploymentName)
+     .AsIChatClient();
+
+// Read command-line arguments
+if (args.Length < 2)
+{
+    Console.WriteLine("Usage: DeclarativeAgents <yaml-file-path> <prompt>");
+    Console.WriteLine("  <yaml-file-path>: The path to the YAML file containing the agent definition");
+    Console.WriteLine("  <prompt>: The prompt to send to the agent");
+    return;
+}
+
+var yamlFilePath = args[0];
+var prompt = args[1];
+
+// Verify the YAML file exists
+if (!File.Exists(yamlFilePath))
+{
+    Console.WriteLine($"Error: File not found: {yamlFilePath}");
+    return;
+}
+
+// Read the YAML content from the file
+var text = await File.ReadAllTextAsync(yamlFilePath);
+
+// Example function tool that can be used by the agent.
+[Description("Get the weather for a given location.")]
+static string GetWeather(
+    [Description("The city and state, e.g. San Francisco, CA")] string location,
+    [Description("The unit of temperature. Possible values are 'celsius' and 'fahrenheit'.")] string unit)
+    => $"The weather in {location} is cloudy with a high of {(unit.Equals("celsius", StringComparison.Ordinal) ? "15°C" : "59°F")}.";
+
+// Create the agent from the YAML definition.
+var agentFactory = new ChatClientPromptAgentFactory(chatClient, [AIFunctionFactory.Create(GetWeather, "GetWeather")]);
+var agent = await agentFactory.CreateFromYamlAsync(text);
+
+// Invoke the agent and output the text result.
+Console.WriteLine(await agent!.RunAsync(prompt));