diff --git a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/IdGenerator.cs b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/IdGenerator.cs
index bd35fa8308..cc03d52887 100644
--- a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/IdGenerator.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/IdGenerator.cs
@@ -34,6 +34,7 @@ internal sealed partial class IdGenerator
         this._random = randomSeed.HasValue ? new Random(randomSeed.Value) : null;
         this.ResponseId = responseId ?? NewId("resp", random: this._random);
         this.ConversationId = conversationId ?? NewId("conv", random: this._random);
+        this.IsNewConversation = conversationId is null;
         this._partitionId = GetPartitionIdOrDefault(this.ConversationId) ?? string.Empty;
     }
 
@@ -59,6 +60,11 @@ internal sealed partial class IdGenerator
     /// </summary>
     public string ConversationId { get; }
 
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool IsNewConversation { get; }
+
     /// <summary>
     /// Generates a new ID.
     /// </summary>
diff --git a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/AgentInvocationContext.cs b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/AgentInvocationContext.cs
index f21c2e84e9..f90450f514 100644
--- a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/AgentInvocationContext.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/AgentInvocationContext.cs
@@ -26,6 +26,8 @@ internal sealed class AgentInvocationContext(IdGenerator idGenerator, JsonSerial
     /// </summary>
     public string ConversationId => this.IdGenerator.ConversationId;
 
+    public bool IsNewConversation => this.IdGenerator.IsNewConversation;
+
     /// <summary>
     /// Gets the JSON serializer options.
     /// </summary>
diff --git a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/HostedAgentResponseExecutor.cs b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/HostedAgentResponseExecutor.cs
index e777bb6e16..78fa89c9ab 100644
--- a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/HostedAgentResponseExecutor.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/HostedAgentResponseExecutor.cs
@@ -77,14 +77,13 @@ internal sealed class HostedAgentResponseExecutor : IResponseExecutor
         [EnumeratorCancellation] CancellationToken cancellationToken = default)
     {
         string agentName = GetAgentName(request)!;
-        var conversationId = request.Conversation?.Id;
+        string conversationId = context.ConversationId;
 
         var agent = this._serviceProvider.GetRequiredKeyedService<AIAgent>(agentName);
         var threadStore = this._serviceProvider.GetKeyedService<AgentThreadStore>(agent.Name);
 
         var chatOptions = new ChatOptions
         {
-            ConversationId = conversationId,
             Temperature = (float?)request.Temperature,
             TopP = (float?)request.TopP,
             MaxOutputTokens = request.MaxOutputTokens,
@@ -94,11 +93,9 @@ internal sealed class HostedAgentResponseExecutor : IResponseExecutor
         var options = new ChatClientAgentRunOptions(chatOptions);
         var messages = new List<ChatMessage>();
 
-        AgentThread? thread = default;
-        if (conversationId is not null && threadStore is not null)
-        {
-            thread = await threadStore.GetThreadAsync(agent, conversationId, cancellationToken).ConfigureAwait(false);
-        }
+        AgentThread thread = !context.IsNewConversation && threadStore is not null
+            ? await threadStore.GetThreadAsync(agent, conversationId, cancellationToken).ConfigureAwait(false)
+            : agent.GetNewThread();
 
         foreach (var inputMessage in request.Input.GetInputMessages())
         {
@@ -111,7 +108,7 @@ internal sealed class HostedAgentResponseExecutor : IResponseExecutor
             yield return streamingEvent;
         }
 
-        if (conversationId is not null && threadStore is not null && thread is not null)
+        if (threadStore is not null && thread is not null)
         {
             await threadStore.SaveThreadAsync(agent, conversationId, thread, cancellationToken).ConfigureAwait(false);
         }