diff --git a/src/pipecat/services/anthropic.py b/src/pipecat/services/anthropic.py
index a80e2154c..6a95d04e2 100644
--- a/src/pipecat/services/anthropic.py
+++ b/src/pipecat/services/anthropic.py
@@ -711,12 +711,13 @@ class AnthropicAssistantContextAggregator(LLMAssistantContextAggregator):
         )
 
     async def handle_function_call_result(self, frame: FunctionCallResultFrame):
-        if not frame.result:
-            return
-
-        result = json.dumps(frame.result)
-
-        await self._update_function_call_result(frame.function_name, frame.tool_call_id, result)
+        if frame.result:
+            result = json.dumps(frame.result)
+            await self._update_function_call_result(frame.function_name, frame.tool_call_id, result)
+        else:
+            await self._update_function_call_result(
+                frame.function_name, frame.tool_call_id, "COMPLETED"
+            )
 
     async def handle_function_call_cancel(self, frame: FunctionCallCancelFrame):
         await self._update_function_call_result(
diff --git a/src/pipecat/services/google/google.py b/src/pipecat/services/google/google.py
index 7aa9b7b7b..bfddce46d 100644
--- a/src/pipecat/services/google/google.py
+++ b/src/pipecat/services/google/google.py
@@ -600,15 +600,19 @@ class GoogleAssistantContextAggregator(OpenAIAssistantContextAggregator):
         )
 
     async def handle_function_call_result(self, frame: FunctionCallResultFrame):
-        if not frame.result:
-            return
+        if frame.result:
+            if not isinstance(frame.result, str):
+                return
 
-        if not isinstance(frame.result, str):
-            return
+            response = {"response": frame.result}
 
-        response = {"response": frame.result}
-
-        await self._update_function_call_result(frame.function_name, frame.tool_call_id, response)
+            await self._update_function_call_result(
+                frame.function_name, frame.tool_call_id, response
+            )
+        else:
+            await self._update_function_call_result(
+                frame.function_name, frame.tool_call_id, "COMPLETED"
+            )
 
     async def handle_function_call_cancel(self, frame: FunctionCallCancelFrame):
         await self._update_function_call_result(
diff --git a/src/pipecat/services/openai.py b/src/pipecat/services/openai.py
index 8318739de..b5f5d9d54 100644
--- a/src/pipecat/services/openai.py
+++ b/src/pipecat/services/openai.py
@@ -584,12 +584,13 @@ class OpenAIAssistantContextAggregator(LLMAssistantContextAggregator):
         )
 
     async def handle_function_call_result(self, frame: FunctionCallResultFrame):
-        if not frame.result:
-            return
-
-        result = json.dumps(frame.result)
-
-        await self._update_function_call_result(frame.function_name, frame.tool_call_id, result)
+        if frame.result:
+            result = json.dumps(frame.result)
+            await self._update_function_call_result(frame.function_name, frame.tool_call_id, result)
+        else:
+            await self._update_function_call_result(
+                frame.function_name, frame.tool_call_id, "COMPLETED"
+            )
 
     async def handle_function_call_cancel(self, frame: FunctionCallCancelFrame):
         await self._update_function_call_result(