update prompt

app.py

@@ -376,11 +376,10 @@ Calculator: Useful for when you need to answer questions about math.
 Text To Sound: Useful when you need to convert text into sound file."""
 
 
-PREFIX = """You are friendly virtual assistant and you should try your best to answer the following question.
-Your response should have detail information and explanation.
+PREFIX = """Answer the following questions as best you can with detail information and explanation. 
 You can always use tools to convert text to sound.
-You must always check internal vector database first and try to answer the question based on the information in internal vector database only.
-Only when there is no information available from vector database, you are allowed to search information by using other tools.
+You must always check internal vector database first and try to answer the question based on the information found in internal vector database only.
+Only when there is no information available from vector database, you can search information by using other tools.
 You have access to the following tools:"""
 
 FORMAT_INSTRUCTIONS = """Use the following format: