diff --git a/app/services/ai_backend/gemini.rb b/app/services/ai_backend/gemini.rb
index 20540119..9ef28f35 100644
--- a/app/services/ai_backend/gemini.rb
+++ b/app/services/ai_backend/gemini.rb
@@ -42,8 +42,8 @@ def set_client_config(config)
 
     @client_config = {
       contents: config[:messages],
-      system_instruction: system_message(config[:instructions])      
-    }
+      system_instruction: ( system_message(config[:instructions]) if @assistant.language_model.supports_system_message?)     
+    }.compact
   end
 
   def get_oneoff_message(instructions, messages, params = {})