diff --git a/llm/default_plugins/openai_models.py b/llm/default_plugins/openai_models.py
index 48abb23..e37067a 100644
--- a/llm/default_plugins/openai_models.py
+++ b/llm/default_plugins/openai_models.py
@@ -527,7 +527,7 @@ class _Shared:
                 messages.append(
                     {"role": "assistant", "content": prev_response.text_or_raise()}
                 )
-                tool_calls = prev_response.tool_calls()
+                tool_calls = prev_response.tool_calls_or_raise()
                 if tool_calls:
                     messages.append(
                         {
diff --git a/llm/models.py b/llm/models.py
index b165113..f6365f5 100644
--- a/llm/models.py
+++ b/llm/models.py
@@ -722,6 +722,9 @@ class Response(_BaseResponse):
         self._force()
         return self._tool_calls
 
+    def tool_calls_or_raise(self) -> str:
+        return self.tool_calls()
+
     def json(self) -> Optional[Dict[str, Any]]:
         self._force()
         return self.response_json
@@ -872,6 +875,11 @@ class AsyncResponse(_BaseResponse):
         await self._force()
         return self._tool_calls
 
+    def tool_calls_or_raise(self) -> str:
+        if not self._done:
+            raise ValueError("Response not yet awaited")
+        return self.tool_calls()
+
     async def json(self) -> Optional[Dict[str, Any]]:
         await self._force()
         return self.response_json