Update app.py

app.py

@@ -1,4 +1,5 @@
 # app.py
+# app.py
 from __future__ import annotations
 import os
 import traceback
@@ -104,28 +105,31 @@ def handle(user_msg: str, history_messages: List[Dict[str, str]], files: list) -
                 # Initialize the Cohere Chat LLM for the agent
                 llm = ChatCohere(model=COHERE_MODEL_PRIMARY, temperature=0)
 
-                # --- PROMPT ENGINEERING FIX ---
-                # This prefix gives the LLM strict instructions to prevent parsing errors.
+                # --- AGGRESSIVE PROMPT ENGINEERING FIX ---
+                # This new prefix explicitly forbids the LLM from outputting an Action and a Final Answer simultaneously.
                 AGENT_PREFIX = """
-                You are working with a pandas dataframe in Python. The name of the dataframe is `df`.
-                You are a data analysis expert providing a structured response.
-                
-                You are given a user query and you must use the python_repl_ast tool to answer.
-
-                RULES:
-                1. You MUST use the python_repl_ast tool to derive your answers.
-                2. You MUST NOT provide a "Final Answer" until you have used the tool and have an observation.
-                3. You MUST work step-by-step. First Think, then use the Action/Action Input, then get an Observation. Do not try to do everything in one step.
-                
-                This is an example of a valid response:
-                Thought: I need to check the column names in the dataframe.
-                Action: python_repl_ast
-                Action Input: print(df.columns)
-
-                Begin!
-                """
-
-                # Create the pandas DataFrame agent with our custom prefix
+You are a data analysis agent working with a pandas dataframe named `df`.
+You must answer the user's query by executing Python code one step at a time.
+
+Your response MUST strictly follow one of two formats:
+
+FORMAT 1: To think and execute code.
+Thought: Your reasoning for the next step. This is mandatory.
+Action: The tool to use, which is always `python_repl_ast`.
+Action Input: The single-line Python code to execute.
+
+FORMAT 2: To give the final answer.
+Thought: I have now gathered all the information needed to answer the user's request.
+Final Answer: The final, comprehensive answer.
+
+CRITICAL RULE: Your response must contain EITHER an "Action" OR a "Final Answer", but NEVER BOTH.
+If you need to run code, use FORMAT 1. If you are finished, use FORMAT 2.
+Do not combine them. Start by thinking about the first step.
+
+Begin!
+"""
+
+                # Create the pandas DataFrame agent with our new, stricter prefix
                 agent = create_pandas_dataframe_agent(
                     llm,
                     df,
@@ -133,7 +137,7 @@ def handle(user_msg: str, history_messages: List[Dict[str, str]], files: list) -
                     verbose=True,
                     allow_dangerous_code=True,
                     handle_parsing_errors=True,
-                    prefix=AGENT_PREFIX  # <-- APPLYING THE PROMPT ENGINEERING FIX
+                    prefix=AGENT_PREFIX  # Applying the new aggressive prompt
                 )
 
                 # Run the agent with the user's scenario text.