diff --git a/g4f/api/__init__.py b/g4f/api/__init__.py
index 9772f8d7..7296a542 100644
--- a/g4f/api/__init__.py
+++ b/g4f/api/__init__.py
@@ -120,7 +120,10 @@ class Api:
                 'created': 0,
                 'owned_by': model.base_provider
             } for model_id, model in model_list.items()]
-            return JSONResponse(model_list)
+            return JSONResponse({
+                "object": "list",
+                "data": model_list,
+            })
 
         @self.app.get("/v1/models/{model_name}")
         async def model_info(model_name: str):
diff --git a/g4f/client/stubs.py b/g4f/client/stubs.py
index 2441e287..ceb51b83 100644
--- a/g4f/client/stubs.py
+++ b/g4f/client/stubs.py
@@ -78,12 +78,14 @@ class ChatCompletionDelta(Model):
     def __init__(self, content: Union[str, None]):
         if content is not None:
             self.content = content
+            self.role = "assistant"
 
     def to_json(self):
         return self.__dict__
 
 class ChatCompletionDeltaChoice(Model):
     def __init__(self, delta: ChatCompletionDelta, finish_reason: Union[str, None]):
+        self.index = 0
         self.delta = delta
         self.finish_reason = finish_reason
 
diff --git a/g4f/typing.py b/g4f/typing.py
index 5d1bc959..710fde4b 100644
--- a/g4f/typing.py
+++ b/g4f/typing.py
@@ -14,7 +14,7 @@ else:
 SHA256 = NewType('sha_256_hash', str)
 CreateResult = Iterator[str]
 AsyncResult = AsyncIterator[str]
-Messages = List[Dict[str, str]]
+Messages = List[Dict[str, Union[str,List[Dict[str,Union[str,Dict[str,str]]]]]]]
 Cookies = Dict[str, str]
 ImageType = Union[str, bytes, IO, Image, None]