chore: import upstream snapshot with attribution

dotnet/samples/02-agents/AGUI/Step02_BackendTools/Server/Program.cs

@@ -0,0 +1,125 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.ComponentModel;
+using System.Text.Json.Serialization;
+using Azure.AI.OpenAI;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using Microsoft.Agents.AI.Hosting.AGUI.AspNetCore;
+using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Options;
+using OpenAI.Chat;
+
+WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
+builder.Services.AddHttpClient().AddLogging();
+builder.Services.ConfigureHttpJsonOptions(options =>
+    options.SerializerOptions.TypeInfoResolverChain.Add(SampleJsonSerializerContext.Default));
+builder.Services.AddAGUIServer();
+
+// WARNING: When adding session persistence (e.g., WithInMemorySessionStore), or running in production,
+// make sure to also register a SessionIsolationKeyProvider to scope sessions by principal in multi-user
+// deployments, e.g.:
+// builder.Services.UseClaimsBasedSessionIsolation(new() { ClaimType = ClaimTypes.NameIdentifier });
+
+WebApplication app = builder.Build();
+
+string endpoint = builder.Configuration["AZURE_OPENAI_ENDPOINT"]
+    ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
+string deploymentName = builder.Configuration["AZURE_OPENAI_DEPLOYMENT_NAME"]
+    ?? throw new InvalidOperationException("AZURE_OPENAI_DEPLOYMENT_NAME is not set.");
+
+// Define the function tool
+[Description("Search for restaurants in a location.")]
+static RestaurantSearchResponse SearchRestaurants(
+    [Description("The restaurant search request")] RestaurantSearchRequest request)
+{
+    // Simulated restaurant data
+    string cuisine = request.Cuisine == "any" ? "Italian" : request.Cuisine;
+
+    return new RestaurantSearchResponse
+    {
+        Location = request.Location,
+        Cuisine = request.Cuisine,
+        Results =
+        [
+            new RestaurantInfo
+            {
+                Name = "The Golden Fork",
+                Cuisine = cuisine,
+                Rating = 4.5,
+                Address = $"123 Main St, {request.Location}"
+            },
+            new RestaurantInfo
+            {
+                Name = "Spice Haven",
+                Cuisine = cuisine == "Italian" ? "Indian" : cuisine,
+                Rating = 4.7,
+                Address = $"456 Oak Ave, {request.Location}"
+            },
+            new RestaurantInfo
+            {
+                Name = "Green Leaf",
+                Cuisine = "Vegetarian",
+                Rating = 4.3,
+                Address = $"789 Elm Rd, {request.Location}"
+            }
+        ]
+    };
+}
+
+// Get JsonSerializerOptions from the configured HTTP JSON options
+Microsoft.AspNetCore.Http.Json.JsonOptions jsonOptions = app.Services.GetRequiredService<IOptions<Microsoft.AspNetCore.Http.Json.JsonOptions>>().Value;
+
+// Create tool with serializer options
+AITool[] tools =
+[
+    AIFunctionFactory.Create(
+        SearchRestaurants,
+        serializerOptions: jsonOptions.SerializerOptions)
+];
+
+// Create the AI agent with tools
+// WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+// In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
+// latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
+ChatClient chatClient = new AzureOpenAIClient(
+        new Uri(endpoint),
+        new DefaultAzureCredential())
+    .GetChatClient(deploymentName);
+
+ChatClientAgent agent = chatClient.AsAIAgent(
+    name: "AGUIAssistant",
+    instructions: "You are a helpful assistant with access to restaurant information.",
+    tools: tools);
+
+// Map the AG-UI agent endpoint
+app.MapAGUIServer("/", agent);
+
+await app.RunAsync();
+
+// Define request/response types for the tool
+internal sealed class RestaurantSearchRequest
+{
+    public string Location { get; set; } = string.Empty;
+    public string Cuisine { get; set; } = "any";
+}
+
+internal sealed class RestaurantSearchResponse
+{
+    public string Location { get; set; } = string.Empty;
+    public string Cuisine { get; set; } = string.Empty;
+    public RestaurantInfo[] Results { get; set; } = [];
+}
+
+internal sealed class RestaurantInfo
+{
+    public string Name { get; set; } = string.Empty;
+    public string Cuisine { get; set; } = string.Empty;
+    public double Rating { get; set; }
+    public string Address { get; set; } = string.Empty;
+}
+
+// JSON serialization context for source generation
+[JsonSerializable(typeof(RestaurantSearchRequest))]
+[JsonSerializable(typeof(RestaurantSearchResponse))]
+internal sealed partial class SampleJsonSerializerContext : JsonSerializerContext;