.NET: Implement Task support for A2A Hosting package

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

@@ -33,6 +33,20 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path)
         => endpoints.MapA2A(agentBuilder, 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="agentBuilder">The configuration builder for <see cref="AIAgent"/>.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path, AgentRunMode agentRunMode)
+    {
+        ArgumentNullException.ThrowIfNull(agentBuilder);
+        return endpoints.MapA2A(agentBuilder.Name, path, agentRunMode);
+    }
+
     /// <summary>
     /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
     /// </summary>
@@ -43,6 +57,21 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path)
         => endpoints.MapA2A(agentName, 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="agentRunMode">Controls the response behavior of the agent run.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentRunMode agentRunMode)
+    {
+        ArgumentNullException.ThrowIfNull(endpoints);
+        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
+        return endpoints.MapA2A(agent, path, _ => { }, agentRunMode);
+    }
+
     /// <summary>
     /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
     /// </summary>
@@ -109,6 +138,37 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard)
         => endpoints.MapA2A(agentName, 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="agentBuilder">The configuration builder for <see cref="AIAgent"/>.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentCard">Agent card info to return on query.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path, AgentCard agentCard, AgentRunMode agentRunMode)
+    {
+        ArgumentNullException.ThrowIfNull(agentBuilder);
+        return endpoints.MapA2A(agentBuilder.Name, path, agentCard, agentRunMode);
+    }
+
+    /// <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>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard, AgentRunMode agentRunMode)
+    {
+        ArgumentNullException.ThrowIfNull(endpoints);
+        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
+        return endpoints.MapA2A(agent, path, agentCard, agentRunMode);
+    }
+
     /// <summary>
     /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
     /// </summary>
@@ -144,10 +204,28 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     /// discovery mechanism.
     /// </remarks>
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager)
+        => endpoints.MapA2A(agentName, path, agentCard, configureTaskManager, AgentRunMode.NonBackground);
+
+    /// <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>
+    /// <param name="configureTaskManager">The callback to configure <see cref="ITaskManager"/>.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</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 IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager, AgentRunMode agentRunMode)
     {
         ArgumentNullException.ThrowIfNull(endpoints);
         var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
-        return endpoints.MapA2A(agent, path, agentCard, configureTaskManager);
+        return endpoints.MapA2A(agent, path, agentCard, configureTaskManager, agentRunMode);
     }
 
     /// <summary>
@@ -160,6 +238,17 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path)
         => 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="agent">The agent to use for A2A protocol integration.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentRunMode agentRunMode)
+        => endpoints.MapA2A(agent, path, _ => { }, agentRunMode);
+
     /// <summary>
     /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
     /// </summary>
@@ -169,13 +258,25 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     /// <param name="configureTaskManager">The callback to configure <see cref="ITaskManager"/>.</param>
     /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, Action<ITaskManager> configureTaskManager)
+        => endpoints.MapA2A(agent, path, configureTaskManager, AgentRunMode.NonBackground);
+
+    /// <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="configureTaskManager">The callback to configure <see cref="ITaskManager"/>.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, Action<ITaskManager> configureTaskManager, AgentRunMode agentRunMode)
     {
         ArgumentNullException.ThrowIfNull(endpoints);
         ArgumentNullException.ThrowIfNull(agent);
 
         var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
         var agentSessionStore = endpoints.ServiceProvider.GetKeyedService<AgentSessionStore>(agent.Name);
-        var taskManager = agent.MapA2A(loggerFactory: loggerFactory, agentSessionStore: agentSessionStore);
+        var taskManager = agent.MapA2A(loggerFactory: loggerFactory, agentSessionStore: agentSessionStore, runMode: agentRunMode);
         var endpointConventionBuilder = endpoints.MapA2A(taskManager, path);
 
         configureTaskManager(taskManager);
@@ -198,6 +299,23 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentCard agentCard)
         => 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>
+    /// <param name="agentCard">Agent card info to return on query.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</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 IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentCard agentCard, AgentRunMode agentRunMode)
+        => endpoints.MapA2A(agent, path, agentCard, _ => { }, agentRunMode);
+
     /// <summary>
     /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
     /// </summary>
@@ -213,13 +331,31 @@ public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpo
     /// discovery mechanism.
     /// </remarks>
     public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager)
+        => endpoints.MapA2A(agent, path, agentCard, configureTaskManager, AgentRunMode.NonBackground);
+
+    /// <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>
+    /// <param name="configureTaskManager">The callback to configure <see cref="ITaskManager"/>.</param>
+    /// <param name="agentRunMode">Controls the response behavior of the agent run.</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 IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager, AgentRunMode agentRunMode)
     {
         ArgumentNullException.ThrowIfNull(endpoints);
         ArgumentNullException.ThrowIfNull(agent);
 
         var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
         var agentSessionStore = endpoints.ServiceProvider.GetKeyedService<AgentSessionStore>(agent.Name);
-        var taskManager = agent.MapA2A(agentCard: agentCard, agentSessionStore: agentSessionStore, loggerFactory: loggerFactory);
+        var taskManager = agent.MapA2A(agentCard: agentCard, agentSessionStore: agentSessionStore, loggerFactory: loggerFactory, runMode: agentRunMode);
         var endpointConventionBuilder = endpoints.MapA2A(taskManager, path);
 
         configureTaskManager(taskManager);

dotnet/src/Microsoft.Agents.AI.Hosting.A2A/A2AHostingJsonUtilities.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Text.Json;
+
+namespace Microsoft.Agents.AI.Hosting.A2A;
+
+/// <summary>
+/// Provides JSON serialization options for A2A Hosting APIs to support AOT and trimming.
+/// </summary>
+public static class A2AHostingJsonUtilities
+{
+    /// <summary>
+    /// Gets the default <see cref="JsonSerializerOptions"/> instance used for A2A Hosting serialization.
+    /// </summary>
+    public static JsonSerializerOptions DefaultOptions { get; } = CreateDefaultOptions();
+
+    private static JsonSerializerOptions CreateDefaultOptions()
+    {
+        JsonSerializerOptions options = new(global::A2A.A2AJsonUtilities.DefaultOptions);
+
+        // Chain in the resolvers from both AgentAbstractionsJsonUtilities and the A2A SDK context.
+        // AgentAbstractionsJsonUtilities is first to ensure M.E.AI types (e.g. ResponseContinuationToken)
+        // are handled via its resolver, followed by the A2A SDK resolver for protocol types.
+        options.TypeInfoResolverChain.Clear();
+        options.TypeInfoResolverChain.Add(AgentAbstractionsJsonUtilities.DefaultOptions.TypeInfoResolver!);
+        options.TypeInfoResolverChain.Add(global::A2A.A2AJsonUtilities.DefaultOptions.TypeInfoResolver!);
+
+        options.MakeReadOnly();
+        return options;
+    }
+}

dotnet/src/Microsoft.Agents.AI.Hosting.A2A/A2ARunDecisionContext.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using A2A;
+
+namespace Microsoft.Agents.AI.Hosting.A2A;
+
+/// <summary>
+/// Provides context for a custom A2A run mode decision.
+/// </summary>
+public sealed class A2ARunDecisionContext
+{
+    internal A2ARunDecisionContext(MessageSendParams messageSendParams)
+    {
+        this.MessageSendParams = messageSendParams;
+    }
+
+    /// <summary>
+    /// Gets the parameters of the incoming A2A message that triggered this run.
+    /// </summary>
+    public MessageSendParams MessageSendParams { get; }
+}