diff --git a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InvokeAgent.cs b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InvokeAgent.cs
index d8c85853..e4465f27 100644
--- a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InvokeAgent.cs
+++ b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InvokeAgent.cs
@@ -77,6 +77,11 @@ public partial class RoutingService
             message.CurrentAgentId = agent.Id;
             message.IsStreaming = response.IsStreaming;
             message.MessageLabel = response.MessageLabel;
+            // Preserve the LLM's chain-of-thought (DeepSeek `reasoning_content`) so it is not
+            // dropped on the final assistant message. `RoleDialogModel.From(...)` rebuilds the
+            // dialog from the sender and would otherwise lose `response.ReasoningContent`, which
+            // the w4c-chatapi relies on for its Reasoning viewer.
+            message.ReasoningContent = response.ReasoningContent;
             dialogs.Add(message);
             Context.AddDialogs([message]);
         }
diff --git a/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs b/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs
index dbaeb82d..c7651e83 100644
--- a/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs
+++ b/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs
@@ -254,10 +254,26 @@ public class ChatCompletionProvider : IChatCompletion
 
             // DeepSeek thinking mode streams the chain-of-thought in `reasoning_content`
             // (delta level). OpenAI SDK 2.12 keeps it as an unknown property in the JsonPatch.
+            // Each delta is forwarded as a stream message carrying `ReasoningContent` (empty
+            // `Content`) so the host (w4c-chatapi) can surface the live reasoning to the UI —
+            // the same `OnReceiveLlmStreamMessage` event the consumer already subscribes to.
             var reasoningDelta = ReadStreamingReasoningContent(choice);
             if (!string.IsNullOrEmpty(reasoningDelta))
             {
                 reasoningContentBuilder.Append(reasoningDelta);
+
+                var reasoning = new RoleDialogModel(AgentRole.Assistant, string.Empty)
+                {
+                    CurrentAgentId = agent.Id,
+                    MessageId = messageId,
+                    ReasoningContent = reasoningDelta
+                };
+                hub.Push(new()
+                {
+                    EventName = ChatEvent.OnReceiveLlmStreamMessage,
+                    RefId = conv.ConversationId,
+                    Data = reasoning
+                });
             }
 
             if (!choice.ContentUpdate.IsNullOrEmpty())