Add sample showing how to use any foundry model (#1159)

dotnet/samples/GettingStarted/AgentProviders/Agent_With_AzureFoundryModel/Program.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample shows how to use the OpenAI SDK to create and use a simple AI agent with any model hosted in Azure AI Foundry.
+// You could use models from Microsoft, OpenAI, DeepSeek, Hugging Face, Meta, xAI or any other model you have deployed in your Azure AI Foundry resource.
+// Note: Ensure that you pick a model that suits your needs. For example, if you want to use function calling, ensure that the model you pick supports function calling.
+
+using System.ClientModel;
+using System.ClientModel.Primitives;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using OpenAI;
+
+var endpoint = Environment.GetEnvironmentVariable("AZURE_FOUNDRY_OPENAI_ENDPOINT") ?? throw new InvalidOperationException("AZURE_FOUNDRY_OPENAI_ENDPOINT is not set.");
+var apiKey = Environment.GetEnvironmentVariable("AZURE_FOUNDRY_OPENAI_APIKEY");
+var model = Environment.GetEnvironmentVariable("AZURE_FOUNDRY_MODEL_DEPLOYMENT") ?? "Phi-4-mini-instruct";
+
+const string JokerName = "Joker";
+const string JokerInstructions = "You are good at telling jokes.";
+
+// Since we are using the OpenAI Client SDK, we need to override the default endpoint to point to Azure Foundry.
+var clientOptions = new OpenAIClientOptions() { Endpoint = new Uri(endpoint) };
+
+// Create the OpenAI client with either an API key or Azure CLI credential.
+OpenAIClient client = string.IsNullOrWhiteSpace(apiKey)
+    ? new OpenAIClient(new BearerTokenPolicy(new AzureCliCredential(), "https://ai.azure.com/.default"), clientOptions)
+    : new OpenAIClient(new ApiKeyCredential(apiKey), clientOptions);
+
+AIAgent agent = client
+     .GetChatClient(model)
+     .CreateAIAgent(JokerInstructions, JokerName);
+
+// Invoke the agent and output the text result.
+Console.WriteLine(await agent.RunAsync("Tell me a joke about a pirate."));