diff --git a/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs b/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs
index 42ce1ac9..eb14ac99 100644
--- a/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs
+++ b/src/Plugins/BotSharp.Plugin.DeepSeekAI/Providers/Chat/ChatCompletionProvider.cs
@@ -270,7 +270,7 @@ public class ChatCompletionProvider : IChatCompletion
             {
                 messages.Add(new AssistantChatMessage(new List<ChatToolCall>
                 {
-                    ChatToolCall.CreateFunctionToolCall(message.ToolCallId.IfNullOrEmptyAs(message.FunctionName), message.FunctionName, BinaryData.FromString(message.FunctionArgs ?? string.Empty))
+                    ChatToolCall.CreateFunctionToolCall(message.ToolCallId.IfNullOrEmptyAs(message.FunctionName), message.FunctionName, BinaryData.FromString(message.FunctionArgs ?? "{}"))
                 }));
 
                 messages.Add(new ToolChatMessage(message.ToolCallId.IfNullOrEmptyAs(message.FunctionName), message.Content));
diff --git a/src/Plugins/BotSharp.Plugin.OpenAI/Providers/Realtime/RealTimeCompletionProvider.cs b/src/Plugins/BotSharp.Plugin.OpenAI/Providers/Realtime/RealTimeCompletionProvider.cs
index 8219bf1c..92fa6f84 100644
--- a/src/Plugins/BotSharp.Plugin.OpenAI/Providers/Realtime/RealTimeCompletionProvider.cs
+++ b/src/Plugins/BotSharp.Plugin.OpenAI/Providers/Realtime/RealTimeCompletionProvider.cs
@@ -615,10 +615,10 @@ public class RealTimeCompletionProvider : IRealTimeCompletion
             {
                 messages.Add(new AssistantChatMessage(new List<ChatToolCall>
                 {
-                    ChatToolCall.CreateFunctionToolCall(message.ToolCallId, message.FunctionName, BinaryData.FromString(message.FunctionArgs ?? string.Empty))
+                    ChatToolCall.CreateFunctionToolCall(message.ToolCallId.IfNullOrEmptyAs(message.FunctionName), message.FunctionName, BinaryData.FromString(message.FunctionArgs ?? "{}"))
                 }));
 
-                messages.Add(new ToolChatMessage(message.ToolCallId, message.Content));
+                messages.Add(new ToolChatMessage(message.ToolCallId.IfNullOrEmptyAs(message.FunctionName), message.Content));
             }
             else if (message.Role == AgentRole.User)
             {