Error during async streaming of OpenAIAgent & multi tool calls (#9207)

* fix: invalid chunk when streaming

* edit condition order

---------

Co-authored-by: lpineau <lpineau@onestock-retail.com>

llama_index/llms/openai.py

@@ -506,16 +506,27 @@ async def gen() -> ChatResponseAsyncGen:
             tool_calls: List[ChoiceDeltaToolCall] = []
 
             is_function = False
+            first_chat_chunk = True
             async for response in await self._aclient.chat.completions.create(
                 messages=message_dicts,
                 stream=True,
                 **self._get_model_kwargs(**kwargs),
             ):
                 response = cast(ChatCompletionChunk, response)
                 if len(response.choices) > 0:
+                    # check if the first chunk has neither content nor tool_calls
+                    # this happens when 1106 models end up calling multiple tools
+                    if (
+                        first_chat_chunk
+                        and response.choices[0].delta.content is None
+                        and response.choices[0].delta.tool_calls is None
+                    ):
+                        first_chat_chunk = False
+                        continue
                     delta = response.choices[0].delta
                 else:
                     delta = ChoiceDelta()
+                first_chat_chunk = False
 
                 # check if this chunk is the start of a function call
                 if delta.tool_calls: