diff --git a/rag/llm/chat_model.py b/rag/llm/chat_model.py
index 3c6ea4d09..55faa6b32 100644
--- a/rag/llm/chat_model.py
+++ b/rag/llm/chat_model.py
@@ -1217,13 +1217,12 @@ class GeminiChat(Base):
 
     def _clean_conf(self, gen_conf):
         for k in list(gen_conf.keys()):
-            if k not in ["temperature", "top_p"]:
+            if k not in ["temperature", "top_p", "max_tokens"]:
                 del gen_conf[k]
         return gen_conf
 
     def _chat(self, history, gen_conf):
         from google.generativeai.types import content_types
-
         system = history[0]["content"] if history and history[0]["role"] == "system" else ""
         hist = []
         for item in history:
@@ -1246,12 +1245,9 @@ class GeminiChat(Base):
 
     def chat_streamly(self, system, history, gen_conf):
         from google.generativeai.types import content_types
-
+        gen_conf = self._clean_conf(gen_conf)
         if system:
             self.model._system_instruction = content_types.to_content(system)
-        for k in list(gen_conf.keys()):
-            if k not in ["temperature", "top_p", "max_tokens"]:
-                del gen_conf[k]
         for item in history:
             if "role" in item and item["role"] == "assistant":
                 item["role"] = "model"