diff --git a/dotnet/src/Microsoft.Agents.AI.GitHub.Copilot/GitHubCopilotAgent.cs b/dotnet/src/Microsoft.Agents.AI.GitHub.Copilot/GitHubCopilotAgent.cs
index 053a08f725..a85c126fd6 100644
--- a/dotnet/src/Microsoft.Agents.AI.GitHub.Copilot/GitHubCopilotAgent.cs
+++ b/dotnet/src/Microsoft.Agents.AI.GitHub.Copilot/GitHubCopilotAgent.cs
@@ -145,11 +145,12 @@ public sealed class GitHubCopilotAgent : AIAgent, IAsyncDisposable
         // Ensure the client is started
         await this.EnsureClientStartedAsync(cancellationToken).ConfigureAwait(false);
 
-        // Create or resume a session with streaming enabled
+        // Create or resume a session with streaming enabled by default
         SessionConfig sessionConfig = this._sessionConfig != null
             ? CopySessionConfig(this._sessionConfig)
             : new SessionConfig { Streaming = true };
 
+        bool isStreaming = sessionConfig.Streaming ?? true;
         CopilotSession copilotSession;
         if (typedSession.SessionId is not null)
         {
@@ -178,7 +179,7 @@ public sealed class GitHubCopilotAgent : AIAgent, IAsyncDisposable
                         break;
 
                     case AssistantMessageEvent assistantMessage:
-                        channel.Writer.TryWrite(this.ConvertToAgentResponseUpdate(assistantMessage));
+                        channel.Writer.TryWrite(this.ConvertToAgentResponseUpdate(assistantMessage, isStreaming));
                         break;
 
                     case AssistantUsageEvent usageEvent:
@@ -271,19 +272,20 @@ public sealed class GitHubCopilotAgent : AIAgent, IAsyncDisposable
     }
 
     /// <summary>
-    /// Copies all supported properties from a source <see cref="SessionConfig"/> into a new instance
-    /// with <see cref="SessionConfigBase.Streaming"/> set to <c>true</c>.
+    /// Copies all supported properties from a source <see cref="SessionConfig"/> into a new instance,
+    /// preserving <see cref="SessionConfigBase.Streaming"/> from the source (defaulting to <c>true</c> if unset).
     /// </summary>
     internal static SessionConfig CopySessionConfig(SessionConfig source)
     {
         SessionConfig copy = source.Clone();
-        copy.Streaming = true;
+        copy.Streaming = source.Streaming ?? true;
         return copy;
     }
 
     /// <summary>
     /// Copies all supported properties from a source <see cref="SessionConfig"/> into a new
-    /// <see cref="ResumeSessionConfig"/> with <see cref="SessionConfigBase.Streaming"/> set to <c>true</c>.
+    /// <see cref="ResumeSessionConfig"/>, preserving <see cref="SessionConfigBase.Streaming"/>
+    /// from the source (defaulting to <c>true</c> if unset).
     /// </summary>
     internal static ResumeSessionConfig CopyResumeSessionConfig(SessionConfig? source)
     {
@@ -306,7 +308,7 @@ public sealed class GitHubCopilotAgent : AIAgent, IAsyncDisposable
             SkillDirectories = source?.SkillDirectories,
             DisabledSkills = source?.DisabledSkills,
             InfiniteSessions = source?.InfiniteSessions,
-            Streaming = true
+            Streaming = source?.Streaming ?? true
         };
     }
 
@@ -325,12 +327,18 @@ public sealed class GitHubCopilotAgent : AIAgent, IAsyncDisposable
         };
     }
 
-    internal AgentResponseUpdate ConvertToAgentResponseUpdate(AssistantMessageEvent assistantMessage)
+    /// <summary>
+    /// Converts an <see cref="AssistantMessageEvent"/> to an <see cref="AgentResponseUpdate"/>.
+    /// When streaming is enabled, text was already delivered via delta events, so only raw metadata is emitted.
+    /// When streaming is disabled, the full message text is emitted as <see cref="TextContent"/>.
+    /// </summary>
+    internal AgentResponseUpdate ConvertToAgentResponseUpdate(AssistantMessageEvent assistantMessage, bool isStreaming)
     {
-        AIContent content = new()
-        {
-            RawRepresentation = assistantMessage
-        };
+        // When streaming, text was already delivered via AssistantMessageDeltaEvent.
+        // When not streaming, this is the only opportunity to emit the response text.
+        AIContent content = isStreaming
+            ? new AIContent { RawRepresentation = assistantMessage }
+            : new TextContent(assistantMessage.Data?.Content ?? string.Empty) { RawRepresentation = assistantMessage };
 
         return new AgentResponseUpdate(ChatRole.Assistant, [content])
         {
diff --git a/dotnet/tests/Microsoft.Agents.AI.GitHub.Copilot.UnitTests/GitHubCopilotAgentTests.cs b/dotnet/tests/Microsoft.Agents.AI.GitHub.Copilot.UnitTests/GitHubCopilotAgentTests.cs
index 944f2f30ab..8faa842eb0 100644
--- a/dotnet/tests/Microsoft.Agents.AI.GitHub.Copilot.UnitTests/GitHubCopilotAgentTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.GitHub.Copilot.UnitTests/GitHubCopilotAgentTests.cs
@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using GitHub.Copilot;
 using GitHub.Copilot.Rpc;
@@ -222,7 +223,73 @@ public sealed class GitHubCopilotAgentTests
     }
 
     [Fact]
-    public void ConvertToAgentResponseUpdate_AssistantMessageEvent_DoesNotEmitTextContent()
+    public void CopySessionConfig_WithStreamingDisabled_PreservesStreamingValue()
+    {
+        // Arrange
+        var source = new SessionConfig
+        {
+            Streaming = false,
+            Model = "gpt-4o",
+        };
+
+        // Act
+        SessionConfig result = GitHubCopilotAgent.CopySessionConfig(source);
+
+        // Assert
+        Assert.False(result.Streaming);
+    }
+
+    [Fact]
+    public void CopySessionConfig_WithStreamingNull_DefaultsToTrue()
+    {
+        // Arrange
+        var source = new SessionConfig
+        {
+            Model = "gpt-4o",
+        };
+
+        // Act
+        SessionConfig result = GitHubCopilotAgent.CopySessionConfig(source);
+
+        // Assert
+        Assert.True(result.Streaming);
+    }
+
+    [Fact]
+    public void CopyResumeSessionConfig_WithStreamingDisabled_PreservesStreamingValue()
+    {
+        // Arrange
+        var source = new SessionConfig
+        {
+            Streaming = false,
+            Model = "gpt-4o",
+        };
+
+        // Act
+        ResumeSessionConfig result = GitHubCopilotAgent.CopyResumeSessionConfig(source);
+
+        // Assert
+        Assert.False(result.Streaming);
+    }
+
+    [Fact]
+    public void CopyResumeSessionConfig_WithStreamingNull_DefaultsToTrue()
+    {
+        // Arrange
+        var source = new SessionConfig
+        {
+            Model = "gpt-4o",
+        };
+
+        // Act
+        ResumeSessionConfig result = GitHubCopilotAgent.CopyResumeSessionConfig(source);
+
+        // Assert
+        Assert.True(result.Streaming);
+    }
+
+    [Fact]
+    public void ConvertToAgentResponseUpdate_AssistantMessageEventWhenStreaming_DoesNotEmitTextContent()
     {
         var assistantMessage = new AssistantMessageEvent
         {
@@ -235,11 +302,84 @@ public sealed class GitHubCopilotAgentTests
         CopilotClient copilotClient = new(new CopilotClientOptions());
         const string TestId = "agent-id";
         var agent = new GitHubCopilotAgent(copilotClient, ownsClient: false, id: TestId, tools: null);
-        AgentResponseUpdate result = agent.ConvertToAgentResponseUpdate(assistantMessage);
+        AgentResponseUpdate result = agent.ConvertToAgentResponseUpdate(assistantMessage, isStreaming: true);
 
-        // result.Text need to be empty because the content was already delivered via delta events, and we want to avoid emitting duplicate content in the response update.
-        // The content should be delivered through TextContent in the Contents collection instead.
+        // result.Text should be empty because content was already delivered via delta events.
         Assert.Empty(result.Text);
         Assert.DoesNotContain(result.Contents, c => c is TextContent);
     }
+
+    [Fact]
+    public void ConvertToAgentResponseUpdate_AssistantMessageEventWhenNotStreaming_EmitsTextContent()
+    {
+        // Arrange
+        const string ExpectedContent = "Full response text from non-streaming session";
+        var assistantMessage = new AssistantMessageEvent
+        {
+            Data = new AssistantMessageData
+            {
+                MessageId = "msg-789",
+                Content = ExpectedContent
+            }
+        };
+        CopilotClient copilotClient = new(new CopilotClientOptions());
+        const string TestId = "agent-id";
+        var agent = new GitHubCopilotAgent(copilotClient, ownsClient: false, id: TestId, tools: null);
+
+        // Act
+        AgentResponseUpdate result = agent.ConvertToAgentResponseUpdate(assistantMessage, isStreaming: false);
+
+        // Assert - text must be emitted since no delta events precede it in non-streaming mode.
+        Assert.Equal(ExpectedContent, result.Text);
+        Assert.Contains(result.Contents, c => c is TextContent);
+        TextContent textContent = (TextContent)result.Contents.Single(c => c is TextContent);
+        Assert.Equal(ExpectedContent, textContent.Text);
+        Assert.Same(assistantMessage, textContent.RawRepresentation);
+    }
+
+    [Fact]
+    public void ConvertToAgentResponseUpdate_AssistantMessageEventWhenNotStreaming_HandlesEmptyContent()
+    {
+        // Arrange
+        var assistantMessage = new AssistantMessageEvent
+        {
+            Data = new AssistantMessageData
+            {
+                MessageId = "msg-000",
+                Content = string.Empty
+            }
+        };
+        CopilotClient copilotClient = new(new CopilotClientOptions());
+        const string TestId = "agent-id";
+        var agent = new GitHubCopilotAgent(copilotClient, ownsClient: false, id: TestId, tools: null);
+
+        // Act
+        AgentResponseUpdate result = agent.ConvertToAgentResponseUpdate(assistantMessage, isStreaming: false);
+
+        // Assert - should emit empty TextContent rather than throwing.
+        Assert.Empty(result.Text);
+        Assert.Contains(result.Contents, c => c is TextContent);
+    }
+
+    [Fact]
+    public void ConvertToAgentResponseUpdate_AssistantMessageEventWhenNotStreaming_HandlesNullData()
+    {
+        // Arrange
+        var assistantMessage = new AssistantMessageEvent
+        {
+            Data = null!
+        };
+        CopilotClient copilotClient = new(new CopilotClientOptions());
+        const string TestId = "agent-id";
+        var agent = new GitHubCopilotAgent(copilotClient, ownsClient: false, id: TestId, tools: null);
+
+        // Act
+        AgentResponseUpdate result = agent.ConvertToAgentResponseUpdate(assistantMessage, isStreaming: false);
+
+        // Assert - null Data should produce empty TextContent via null-propagation fallback.
+        Assert.Empty(result.Text);
+        Assert.Contains(result.Contents, c => c is TextContent);
+        Assert.Null(result.MessageId);
+        Assert.Null(result.ResponseId);
+    }
 }