diff --git a/dotnet/src/Microsoft.Agents.AI.OpenAI/Extensions/OpenAIResponseClientExtensions.cs b/dotnet/src/Microsoft.Agents.AI.OpenAI/Extensions/OpenAIResponseClientExtensions.cs
index 98561704f2..09046e1822 100644
--- a/dotnet/src/Microsoft.Agents.AI.OpenAI/Extensions/OpenAIResponseClientExtensions.cs
+++ b/dotnet/src/Microsoft.Agents.AI.OpenAI/Extensions/OpenAIResponseClientExtensions.cs
@@ -100,15 +100,23 @@ public static ChatClientAgent AsAIAgent(
     /// This corresponds to setting the "store" property in the JSON representation to false.
     /// </remarks>
     /// <param name="responseClient">The client.</param>
+    /// <param name="includeReasoningEncryptedContent">
+    /// Includes an encrypted version of reasoning tokens in reasoning item outputs.
+    /// This enables reasoning items to be used in multi-turn conversations when using the Responses API statelessly
+    /// (like when the store parameter is set to false, or when an organization is enrolled in the zero data retention program).
+    /// Defaults to <see langword="true"/>.
+    /// </param>
     /// <returns>An <see cref="IChatClient"/> that can be used to converse via the <see cref="ResponsesClient"/> that does not store responses for later retrieval.</returns>
     /// <exception cref="ArgumentNullException"><paramref name="responseClient"/> is <see langword="null"/>.</exception>
     [Experimental(DiagnosticIds.Experiments.AgentsAIExperiments)]
-    public static IChatClient AsIChatClientWithStoredOutputDisabled(this ResponsesClient responseClient)
+    public static IChatClient AsIChatClientWithStoredOutputDisabled(this ResponsesClient responseClient, bool includeReasoningEncryptedContent = true)
     {
         return Throw.IfNull(responseClient)
             .AsIChatClient()
             .AsBuilder()
-            .ConfigureOptions(x => x.RawRepresentationFactory = _ => new CreateResponseOptions() { StoredOutputEnabled = false })
+            .ConfigureOptions(x => x.RawRepresentationFactory = _ => includeReasoningEncryptedContent
+                ? new CreateResponseOptions() { StoredOutputEnabled = false, IncludedProperties = { IncludedResponseProperty.ReasoningEncryptedContent } }
+                : new CreateResponseOptions() { StoredOutputEnabled = false })
             .Build();
     }
 }
diff --git a/dotnet/tests/Microsoft.Agents.AI.OpenAI.UnitTests/Extensions/OpenAIResponseClientExtensionsTests.cs b/dotnet/tests/Microsoft.Agents.AI.OpenAI.UnitTests/Extensions/OpenAIResponseClientExtensionsTests.cs
index 19a39c1d35..1205889e19 100644
--- a/dotnet/tests/Microsoft.Agents.AI.OpenAI.UnitTests/Extensions/OpenAIResponseClientExtensionsTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.OpenAI.UnitTests/Extensions/OpenAIResponseClientExtensionsTests.cs
@@ -291,6 +291,85 @@ public void AsIChatClientWithStoredOutputDisabled_InnerResponsesClientIsAccessib
         Assert.Same(responseClient, innerClient);
     }
 
+    /// <summary>
+    /// Verify that AsIChatClientWithStoredOutputDisabled with includeReasoningEncryptedContent false
+    /// wraps the original ResponsesClient, which remains accessible via the service chain.
+    /// </summary>
+    [Fact]
+    public void AsIChatClientWithStoredOutputDisabled_WithIncludeReasoningFalse_InnerResponsesClientIsAccessible()
+    {
+        // Arrange
+        var responseClient = new TestOpenAIResponseClient();
+
+        // Act
+        var chatClient = responseClient.AsIChatClientWithStoredOutputDisabled(includeReasoningEncryptedContent: false);
+
+        // Assert - the inner ResponsesClient should be accessible via GetService
+        var innerClient = chatClient.GetService<ResponsesClient>();
+        Assert.NotNull(innerClient);
+        Assert.Same(responseClient, innerClient);
+    }
+
+    /// <summary>
+    /// Verify that AsIChatClientWithStoredOutputDisabled with default parameter (includeReasoningEncryptedContent = true)
+    /// configures StoredOutputEnabled to false and includes ReasoningEncryptedContent in IncludedProperties.
+    /// </summary>
+    [Fact]
+    public void AsIChatClientWithStoredOutputDisabled_Default_ConfiguresStoredOutputDisabledWithReasoningEncryptedContent()
+    {
+        // Arrange
+        var responseClient = new TestOpenAIResponseClient();
+
+        // Act
+        var chatClient = responseClient.AsIChatClientWithStoredOutputDisabled();
+
+        // Assert
+        var createResponseOptions = GetCreateResponseOptionsFromPipeline(chatClient);
+        Assert.NotNull(createResponseOptions);
+        Assert.False(createResponseOptions.StoredOutputEnabled);
+        Assert.Contains(IncludedResponseProperty.ReasoningEncryptedContent, createResponseOptions.IncludedProperties);
+    }
+
+    /// <summary>
+    /// Verify that AsIChatClientWithStoredOutputDisabled with includeReasoningEncryptedContent explicitly set to true
+    /// configures StoredOutputEnabled to false and includes ReasoningEncryptedContent in IncludedProperties.
+    /// </summary>
+    [Fact]
+    public void AsIChatClientWithStoredOutputDisabled_WithIncludeReasoningTrue_ConfiguresStoredOutputDisabledWithReasoningEncryptedContent()
+    {
+        // Arrange
+        var responseClient = new TestOpenAIResponseClient();
+
+        // Act
+        var chatClient = responseClient.AsIChatClientWithStoredOutputDisabled(includeReasoningEncryptedContent: true);
+
+        // Assert
+        var createResponseOptions = GetCreateResponseOptionsFromPipeline(chatClient);
+        Assert.NotNull(createResponseOptions);
+        Assert.False(createResponseOptions.StoredOutputEnabled);
+        Assert.Contains(IncludedResponseProperty.ReasoningEncryptedContent, createResponseOptions.IncludedProperties);
+    }
+
+    /// <summary>
+    /// Verify that AsIChatClientWithStoredOutputDisabled with includeReasoningEncryptedContent set to false
+    /// configures StoredOutputEnabled to false and does not include ReasoningEncryptedContent in IncludedProperties.
+    /// </summary>
+    [Fact]
+    public void AsIChatClientWithStoredOutputDisabled_WithIncludeReasoningFalse_ConfiguresStoredOutputDisabledWithoutReasoningEncryptedContent()
+    {
+        // Arrange
+        var responseClient = new TestOpenAIResponseClient();
+
+        // Act
+        var chatClient = responseClient.AsIChatClientWithStoredOutputDisabled(includeReasoningEncryptedContent: false);
+
+        // Assert
+        var createResponseOptions = GetCreateResponseOptionsFromPipeline(chatClient);
+        Assert.NotNull(createResponseOptions);
+        Assert.False(createResponseOptions.StoredOutputEnabled);
+        Assert.DoesNotContain(IncludedResponseProperty.ReasoningEncryptedContent, createResponseOptions.IncludedProperties);
+    }
+
     /// <summary>
     /// A simple test IServiceProvider implementation for testing.
     /// </summary>
@@ -309,4 +388,24 @@ private sealed class TestServiceProvider : IServiceProvider
             BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
         return property?.GetValue(client) as IServiceProvider;
     }
+
+    /// <summary>
+    /// Extracts the <see cref="CreateResponseOptions"/> produced by the ConfigureOptions pipeline
+    /// by using reflection to access the configure action and invoking it on a test <see cref="ChatOptions"/>.
+    /// </summary>
+    private static CreateResponseOptions? GetCreateResponseOptionsFromPipeline(IChatClient chatClient)
+    {
+        // The ConfigureOptionsChatClient stores the configure action in a private field.
+        var configureField = chatClient.GetType().GetField("_configureOptions", BindingFlags.NonPublic | BindingFlags.Instance);
+        Assert.NotNull(configureField);
+
+        var configureAction = configureField.GetValue(chatClient) as Action<ChatOptions>;
+        Assert.NotNull(configureAction);
+
+        var options = new ChatOptions();
+        configureAction(options);
+
+        Assert.NotNull(options.RawRepresentationFactory);
+        return options.RawRepresentationFactory(chatClient) as CreateResponseOptions;
+    }
 }
diff --git a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/Extensions/ChatMessageExtensionsTests.cs b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/Extensions/ChatMessageExtensionsTests.cs
index 5dae26e348..833ab0d402 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/Extensions/ChatMessageExtensionsTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/Extensions/ChatMessageExtensionsTests.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Microsoft. All rights reserved.
 
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.Agents.AI.Workflows.Declarative.Extensions;
diff --git a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/EditTableExecutorTest.cs b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/EditTableExecutorTest.cs
index ad9d51c2fe..77e7f45ff6 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/EditTableExecutorTest.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/EditTableExecutorTest.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Microsoft. All rights reserved.
 
-using System;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
diff --git a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/RequestExternalInputExecutorTest.cs b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/RequestExternalInputExecutorTest.cs
index 1e11f1a0ae..8eda895b15 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/RequestExternalInputExecutorTest.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/RequestExternalInputExecutorTest.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Microsoft. All rights reserved.
 
-using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;