update instruction

app.py

@@ -7,10 +7,22 @@ import os
 from typing import Dict, Any
 
 # System prompt (must match training)
-SYSTEM_PROMPT = """Determine if the message is a restaurant reservation. 
-If yes, extract num_people, reservation_date, 
-and phone_num. If no, all fields must be empty strings. 
-The output must be strictly JSON with no additional text.
+SYSTEM_PROMPT = """Determine if the message is a restaurant reservation request.  
+If yes, extract the following three fields as strings:
+- "num_people": number of people (as a string, e.g., "4"). If not mentioned, use an empty string ("").
+- "reservation_date": the exact date/time phrase from the message (as a string, do not convert or interpret; e.g., keep "明天晚上7點" as is). If not mentioned, use an empty string ("").
+- "phone_num": the phone number (as a string, digits only, remove any hyphens or formatting; e.g., "0912345678"). If not mentioned, use an empty string ("").
+
+If the message is NOT a reservation request, return:
+```json
+{
+  "num_people": "",
+  "reservation_date": "",
+  "phone_num": ""
+}
+```
+
+Output must be valid JSON only, with exactly these three fields and no additional text, fields, or explanations.
 """
 
 # Global variables for model caching