diff --git a/dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgent.cs b/dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgent.cs
index fe73ee1257..4f297f6eca 100644
--- a/dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgent.cs
+++ b/dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgent.cs
@@ -145,8 +145,6 @@ public sealed class ChatClientAgent : AIAgent
         foreach (ChatMessage chatResponseMessage in chatResponse.Messages)
         {
             chatResponseMessage.AuthorName ??= agentName;
-            chatResponseMessage.MessageId ??= Guid.NewGuid().ToString("N");
-            chatResponseMessage.CreatedAt ??= DateTimeOffset.UtcNow;
         }
 
         // Only notify the thread of new messages if the chatResponse was successful to avoid inconsistent message state in the thread.
@@ -233,15 +231,12 @@ public sealed class ChatClientAgent : AIAgent
             throw;
         }
 
-        string? messageId = null;
         while (hasUpdates)
         {
             var update = responseUpdatesEnumerator.Current;
             if (update is not null)
             {
                 update.AuthorName ??= this.Name;
-                update.CreatedAt ??= DateTimeOffset.UtcNow;
-                update.MessageId ??= (messageId ??= Guid.NewGuid().ToString("N"));
 
                 responseUpdates.Add(update);
                 yield return new(update) { AgentId = this.Id };