.NET: Refactor A2A and AIAgent hosting extensions

dotnet/samples/A2AClientServer/A2AServer/A2AServer.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
@@ -9,14 +9,16 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="A2A.AspNetCore" />
     <PackageReference Include="Azure.AI.Agents.Persistent" />
     <PackageReference Include="Azure.Identity" />
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" VersionOverride="10.0.0-rc.2.25502.107" />
     <PackageReference Include="System.Net.ServerSentEvents" VersionOverride="10.0.0-rc.2.25502.107" />
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\..\..\src\Microsoft.Agents.AI.Hosting.A2A.AspNetCore\Microsoft.Agents.AI.Hosting.A2A.AspNetCore.csproj" />
+    <ProjectReference Include="..\..\..\src\Microsoft.Agents.AI.Hosting.A2A\Microsoft.Agents.AI.Hosting.A2A.csproj" />
+
     <ProjectReference Include="..\..\..\src\Microsoft.Agents.AI.A2A\Microsoft.Agents.AI.A2A.csproj" />
     <ProjectReference Include="..\..\..\src\Microsoft.Agents.AI.AzureAI\Microsoft.Agents.AI.AzureAI.csproj" />
     <ProjectReference Include="..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />

dotnet/samples/A2AClientServer/A2AServer/HostAgentFactory.cs

@@ -4,15 +4,14 @@
 using Azure.AI.Agents.Persistent;
 using Azure.Identity;
 using Microsoft.Agents.AI;
-using Microsoft.Agents.AI.A2A;
 using Microsoft.Extensions.AI;
 using OpenAI;
 
 namespace A2AServer;
 
 internal static class HostAgentFactory
 {
-    internal static async Task<A2AHostAgent> CreateFoundryHostAgentAsync(string agentType, string model, string endpoint, string assistantId, IList<AITool>? tools = null)
+    internal static async Task<(AIAgent, AgentCard)> CreateFoundryHostAgentAsync(string agentType, string model, string endpoint, string assistantId, IList<AITool>? tools = null)
     {
         var persistentAgentsClient = new PersistentAgentsClient(endpoint, new AzureCliCredential());
         PersistentAgent persistentAgent = await persistentAgentsClient.Administration.GetAgentAsync(assistantId);
@@ -28,10 +27,10 @@ internal static async Task<A2AHostAgent> CreateFoundryHostAgentAsync(string agen
             _ => throw new ArgumentException($"Unsupported agent type: {agentType}"),
         };
 
-        return new A2AHostAgent(agent, agentCard);
+        return new(agent, agentCard);
     }
 
-    internal static async Task<A2AHostAgent> CreateChatCompletionHostAgentAsync(string agentType, string model, string apiKey, string name, string instructions, IList<AITool>? tools = null)
+    internal static async Task<(AIAgent, AgentCard)> CreateChatCompletionHostAgentAsync(string agentType, string model, string apiKey, string name, string instructions, IList<AITool>? tools = null)
     {
         AIAgent agent = new OpenAIClient(apiKey)
              .GetChatClient(model)
@@ -45,7 +44,7 @@ internal static async Task<A2AHostAgent> CreateChatCompletionHostAgentAsync(stri
             _ => throw new ArgumentException($"Unsupported agent type: {agentType}"),
         };
 
-        return new A2AHostAgent(agent, agentCard);
+        return new(agent, agentCard);
     }
 
     #region private

dotnet/samples/A2AClientServer/A2AServer/Program.cs

@@ -2,7 +2,7 @@
 using A2A;
 using A2A.AspNetCore;
 using A2AServer;
-using Microsoft.Agents.AI.A2A;
+using Microsoft.Agents.AI;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Configuration;
@@ -47,10 +47,12 @@
     AIFunctionFactory.Create(invoiceQueryPlugin.QueryByInvoiceId)
     ];
 
-A2AHostAgent? hostAgent = null;
+AIAgent hostA2AAgent;
+AgentCard hostA2AAgentCard;
+
 if (!string.IsNullOrEmpty(endpoint) && !string.IsNullOrEmpty(agentId))
 {
-    hostAgent = agentType.ToUpperInvariant() switch
+    (hostA2AAgent, hostA2AAgentCard) = agentType.ToUpperInvariant() switch
     {
         "INVOICE" => await HostAgentFactory.CreateFoundryHostAgentAsync(agentType, model, endpoint, agentId, tools),
         "POLICY" => await HostAgentFactory.CreateFoundryHostAgentAsync(agentType, model, endpoint, agentId),
@@ -60,7 +62,7 @@
 }
 else if (!string.IsNullOrEmpty(apiKey))
 {
-    hostAgent = agentType.ToUpperInvariant() switch
+    (hostA2AAgent, hostA2AAgentCard) = agentType.ToUpperInvariant() switch
     {
         "INVOICE" => await HostAgentFactory.CreateChatCompletionHostAgentAsync(
             agentType, model, apiKey, "InvoiceAgent",
@@ -102,7 +104,7 @@ You specialize in handling queries related to logistics.
     throw new ArgumentException("Either A2AServer:ApiKey or A2AServer:ConnectionString & agentId must be provided");
 }
 
-app.MapA2A(hostAgent!.TaskManager!, "/");
-app.MapWellKnownAgentCard(hostAgent!.TaskManager!, "/");
+var a2aTaskManager = app.MapA2A(hostA2AAgent, path: "/", agentCard: hostA2AAgentCard);
+app.MapWellKnownAgentCard(a2aTaskManager, "/");
 
 await app.RunAsync();

dotnet/samples/AgentWebChat/AgentWebChat.AgentHost/Program.cs

@@ -5,7 +5,6 @@
 using AgentWebChat.AgentHost.Utilities;
 using Microsoft.Agents.AI;
 using Microsoft.Agents.AI.Hosting;
-using Microsoft.Agents.AI.Hosting.A2A.AspNetCore;
 using Microsoft.Agents.AI.Workflows;
 using Microsoft.Extensions.AI;
 

dotnet/src/Microsoft.Agents.AI.Hosting.A2A.AspNetCore/EndpointRouteBuilderExtensions.cs

@@ -0,0 +1,103 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using A2A;
+using A2A.AspNetCore;
+using Microsoft.Agents.AI;
+using Microsoft.Agents.AI.Hosting.A2A;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.AspNetCore.Builder;
+
+/// <summary>
+/// Provides extension methods for configuring A2A (Agent2Agent) communication in a host application builder.
+/// </summary>
+public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
+{
+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agentName">The name of the agent to use for A2A protocol integration.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static ITaskManager MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path)
+    {
+        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
+        return endpoints.MapA2A(agent, path);
+    }
+
+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agentName">The name of the agent to use for A2A protocol integration.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentCard">Agent card info to return on query.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    /// <remarks>
+    /// This method can be used to access A2A agents that support the
+    /// <see href="https://github.com/a2aproject/A2A/blob/main/docs/topics/agent-discovery.md#2-curated-registries-catalog-based-discovery">Curated Registries (Catalog-Based Discovery)</see>
+    /// discovery mechanism.
+    /// </remarks>
+    public static ITaskManager MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard)
+    {
+        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
+        return endpoints.MapA2A(agent, path, agentCard);
+    }
+
+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agent">The agent to use for A2A protocol integration.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static ITaskManager MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path)
+    {
+        var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
+        var taskManager = agent.MapA2A(loggerFactory: loggerFactory);
+        return endpoints.MapA2A(taskManager, path);
+    }
+
+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agent">The agent to use for A2A protocol integration.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentCard">Agent card info to return on query.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    /// <remarks>
+    /// This method can be used to access A2A agents that support the
+    /// <see href="https://github.com/a2aproject/A2A/blob/main/docs/topics/agent-discovery.md#2-curated-registries-catalog-based-discovery">Curated Registries (Catalog-Based Discovery)</see>
+    /// discovery mechanism.
+    /// </remarks>
+    public static ITaskManager MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentCard agentCard)
+    {
+        var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
+        var taskManager = agent.MapA2A(agentCard: agentCard, loggerFactory: loggerFactory);
+        return endpoints.MapA2A(taskManager, path);
+    }
+
+    /// <summary>
+    /// Maps HTTP A2A communication endpoints to the specified path using the provided TaskManager.
+    /// TaskManager should be preconfigured before calling this method.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="taskManager">Pre-configured A2A TaskManager to use for A2A endpoints handling.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static ITaskManager MapA2A(this IEndpointRouteBuilder endpoints, TaskManager taskManager, string path)
+    {
+        // note: current SDK version registers multiple `.well-known/agent.json` handlers here.
+        // it makes app return HTTP 500, but will be fixed once new A2A SDK is released.
+        // see https://github.com/microsoft/agent-framework/issues/476 for details
+        A2ARouteBuilderExtensions.MapA2A(endpoints, taskManager, path);
+        endpoints.MapHttpA2A(taskManager, path);
+
+        return taskManager;
+    }
+}