make system message empty by default

app.py

@@ -23,7 +23,11 @@ def respond(
     temperature,
     top_p,
 ):
-    messages = [{"role": "system", "content": system_message}]
+    if len(system_message) > 0:
+        messages = [{"role": "system", "content": system_message}]
+    else:
+        messages = []
+        
 
     for val in history:
         if val[0]:
@@ -54,7 +58,7 @@ demo = gr.ChatInterface(
     respond,
     additional_inputs=[
         gr.Textbox(
-            value="You are a helpful assistant.",
+            value="",
             label="System message",
         ),
         gr.Slider(minimum=200, maximum=100000, value=4000, step=100, label="Max new tokens"),