.NET: Add WithAITool extensions for Hosting AIAgents (#1990)

* add extensions to register tools via fluentAPI

* fix

dotnet/src/Microsoft.Agents.AI.Hosting/AgentHostingServiceCollectionExtensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using Microsoft.Agents.AI.Hosting.Local;
 using Microsoft.Extensions.AI;
@@ -29,7 +30,8 @@ public static class AgentHostingServiceCollectionExtensions
         return services.AddAIAgent(name, (sp, key) =>
         {
             var chatClient = sp.GetRequiredService<IChatClient>();
-            return new ChatClientAgent(chatClient, instructions, key);
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions, key, tools: tools);
         });
     }
 
@@ -46,7 +48,11 @@ public static class AgentHostingServiceCollectionExtensions
     {
         Throw.IfNull(services);
         Throw.IfNullOrEmpty(name);
-        return services.AddAIAgent(name, (sp, key) => new ChatClientAgent(chatClient, instructions, key));
+        return services.AddAIAgent(name, (sp, key) =>
+        {
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions, key, tools: tools);
+        });
     }
 
     /// <summary>
@@ -65,7 +71,8 @@ public static class AgentHostingServiceCollectionExtensions
         return services.AddAIAgent(name, (sp, key) =>
         {
             var chatClient = chatClientServiceKey is null ? sp.GetRequiredService<IChatClient>() : sp.GetRequiredKeyedService<IChatClient>(chatClientServiceKey);
-            return new ChatClientAgent(chatClient, instructions, key);
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions, key, tools: tools);
         });
     }
 
@@ -86,7 +93,8 @@ public static class AgentHostingServiceCollectionExtensions
         return services.AddAIAgent(name, (sp, key) =>
         {
             var chatClient = chatClientServiceKey is null ? sp.GetRequiredService<IChatClient>() : sp.GetRequiredKeyedService<IChatClient>(chatClientServiceKey);
-            return new ChatClientAgent(chatClient, instructions: instructions, name: key, description: description);
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions: instructions, name: key, description: description, tools: tools);
         });
     }
 
@@ -142,4 +150,10 @@ public static class AgentHostingServiceCollectionExtensions
         services.Add(ServiceDescriptor.Singleton(agentHostBuilderContext));
         services.AddSingleton<AgentCatalog, LocalAgentCatalog>();
     }
+
+    private static IList<AITool> GetRegisteredToolsForAgent(IServiceProvider serviceProvider, string agentName)
+    {
+        var registry = serviceProvider.GetService<LocalAgentToolRegistry>();
+        return registry?.GetTools(agentName) ?? [];
+    }
 }

dotnet/src/Microsoft.Agents.AI.Hosting/HostedAgentBuilderExtensions.cs

@@ -1,6 +1,9 @@
 // Copyright (c) Microsoft. All rights reserved.
 
 using System;
+using System.Linq;
+using Microsoft.Agents.AI.Hosting.Local;
+using Microsoft.Extensions.AI;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Shared.Diagnostics;
 
@@ -59,4 +62,52 @@ public static class HostedAgentBuilderExtensions
         });
         return builder;
     }
+
+    /// <summary>
+    /// Adds an AI tool to an agent being configured with the service collection.
+    /// </summary>
+    /// <param name="builder">The hosted agent builder.</param>
+    /// <param name="tool">The AI tool to add to the agent.</param>
+    /// <returns>The same <see cref="IHostedAgentBuilder"/> instance so that additional calls can be chained.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/> or <paramref name="tool"/> is <see langword="null"/>.</exception>
+    public static IHostedAgentBuilder WithAITool(this IHostedAgentBuilder builder, AITool tool)
+    {
+        Throw.IfNull(builder);
+        Throw.IfNull(tool);
+
+        var agentName = builder.Name;
+        var services = builder.ServiceCollection;
+
+        // Get or create the agent tool registry
+        var descriptor = services.FirstOrDefault(sd => !sd.IsKeyedService && sd.ServiceType.Equals(typeof(LocalAgentToolRegistry)));
+        if (descriptor?.ImplementationInstance is not LocalAgentToolRegistry toolRegistry)
+        {
+            toolRegistry = new();
+            services.Add(ServiceDescriptor.Singleton(toolRegistry));
+        }
+
+        toolRegistry.AddTool(agentName, tool);
+
+        return builder;
+    }
+
+    /// <summary>
+    /// Adds multiple AI tools to an agent being configured with the service collection.
+    /// </summary>
+    /// <param name="builder">The hosted agent builder.</param>
+    /// <param name="tools">The collection of AI tools to add to the agent.</param>
+    /// <returns>The same <see cref="IHostedAgentBuilder"/> instance so that additional calls can be chained.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/> or <paramref name="tools"/> is <see langword="null"/>.</exception>
+    public static IHostedAgentBuilder WithAITools(this IHostedAgentBuilder builder, params AITool[] tools)
+    {
+        Throw.IfNull(builder);
+        Throw.IfNull(tools);
+
+        foreach (var tool in tools)
+        {
+            builder.WithAITool(tool);
+        }
+
+        return builder;
+    }
 }

dotnet/src/Microsoft.Agents.AI.Hosting/Local/LocalAgentToolRegistry.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI.Hosting.Local;
+
+internal sealed class LocalAgentToolRegistry
+{
+    private readonly Dictionary<string, List<AITool>> _toolsByAgentName = new();
+
+    public void AddTool(string agentName, AITool tool)
+    {
+        if (!this._toolsByAgentName.TryGetValue(agentName, out var tools))
+        {
+            tools = [];
+            this._toolsByAgentName[agentName] = tools;
+        }
+
+        tools.Add(tool);
+    }
+
+    public IList<AITool> GetTools(string agentName)
+    {
+        return this._toolsByAgentName.TryGetValue(agentName, out var tools) ? tools : [];
+    }
+}

dotnet/src/Microsoft.Agents.AI/Microsoft.Agents.AI.csproj

@@ -31,8 +31,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <InternalsVisibleTo Include="Microsoft.Agents.AI.UnitTests" />
     <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
+
+    <InternalsVisibleTo Include="Microsoft.Agents.AI.UnitTests" />
+    <InternalsVisibleTo Include="Microsoft.Agents.AI.Hosting.UnitTests"/>
   </ItemGroup>
 
 </Project>