Update app.py

fix list error

app.py

@@ -38,11 +38,11 @@ try:
     from langchain_community.callbacks import StreamlitCallbackHandler
     from langchain_community.document_loaders import PyPDFLoader
     from langchain_text_splitters import CharacterTextSplitter
-    from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
+    from langchain_core.prompts import PromptTemplate  # Changed for ReAct
     from langchain_core.runnables import RunnablePassthrough
     from langchain_core.output_parsers import StrOutputParser
     from langchain_core.tools import tool
-    from langchain.agents import AgentExecutor, create_tool_calling_agent
+    from langchain.agents import AgentExecutor, create_react_agent # Changed Agent Type
 except ImportError as e:
     st.error(f"❌ Import Error: {e}")
     st.stop()
@@ -78,14 +78,14 @@ def run_query(query, params=()):
 # ==========================================
 @tool
 def get_credit_score(user_id: str) -> str:
-    """Queries SQL DB for Credit Score."""
+    """Queries SQL DB for Credit Score. Input is just the numeric ID string."""
     clean_id = ''.join(filter(str.isdigit, str(user_id)))
     row = run_query("SELECT Credit_Score FROM credit_score WHERE ID = ?", (clean_id,))
     return f"Credit Score: {row[0]}" if (row and not isinstance(row, str)) else "User ID not found."
 
 @tool
 def get_account_status(user_id: str) -> str:
-    """Queries SQL DB for Name, Nationality, Status, and Email."""
+    """Queries SQL DB for Name, Nationality, Status, and Email. Input is ID string."""
     clean_id = ''.join(filter(str.isdigit, str(user_id)))
     row = run_query("SELECT Name, Nationality, Account_Status, Email FROM account_status WHERE ID = ?", (clean_id,))
     if row and not isinstance(row, str):
@@ -94,7 +94,7 @@ def get_account_status(user_id: str) -> str:
 
 @tool
 def check_pr_status(user_id: str) -> str:
-    """Queries SQL DB for PR Status."""
+    """Queries SQL DB for PR Status. Input is ID string."""
     clean_id = ''.join(filter(str.isdigit, str(user_id)))
     row = run_query("SELECT PR_Status FROM pr_status WHERE ID = ?", (clean_id,))
     if not row or (isinstance(row, str) and "no such column" in row.lower()):
@@ -201,7 +201,7 @@ if st.session_state.get('auth_status', False):
             model_name="llama-3.3-70b-versatile"
         )
     else:
-        # Use Gemini 1.5 Flash (Better for Tools)
+        # Use Gemini 1.5 Flash
         llm = ChatGoogleGenerativeAI(
             google_api_key=current_key, 
             temperature=0, 
@@ -212,29 +212,49 @@ if st.session_state.get('auth_status', False):
     # --- RAG CHAIN ---
     rag_chain = (
         {"context": retriever | (lambda d: "\n".join([x.page_content for x in d])), "question": RunnablePassthrough()}
-        | ChatPromptTemplate.from_template("{context}\nQ:{question}") | llm | StrOutputParser()
+        | PromptTemplate.from_template("Answer based on context:\n{context}\nQuestion: {question}") 
+        | llm 
+        | StrOutputParser()
     )
     
     @tool
     def consult_policy_doc(query: str) -> str:
-        """Consults Policy Documents."""
+        """Consults Policy Documents. Input should be a question string."""
         return rag_chain.invoke(query)
 
     tools = [get_credit_score, get_account_status, check_pr_status, consult_policy_doc]
     
-    prompt = ChatPromptTemplate.from_messages([
-        ("system", "Act as a Loan Officer. Query SQL DB for info. Check Policies via tool. Output Markdown report."),
-        ("human", "{input}"),
-        MessagesPlaceholder(variable_name="agent_scratchpad"),
-    ])
+    # --- REACT AGENT TEMPLATE (Universal Compatibility) ---
+    template = '''Answer the following questions as best you can. You have access to the following tools:
+
+{tools}
+
+Use the following format:
+
+Question: the input question you must answer
+Thought: you should always think about what to do
+Action: the action to take, should be one of [{tool_names}]
+Action Input: the input to the action
+Observation: the result of the action
+... (this Thought/Action/Action Input/Observation can repeat N times)
+Thought: I now know the final answer
+Final Answer: the final answer to the original input question
+
+Begin!
+
+Question: {input}
+Thought:{agent_scratchpad}'''
+
+    prompt = PromptTemplate.from_template(template)
+    
+    # Switch to create_react_agent (More Robust than tool_calling_agent)
+    agent = create_react_agent(llm, tools, prompt)
     
-    # --- AGENT EXECUTOR WITH ERROR HANDLING ---
     agent_executor = AgentExecutor(
-        agent=create_tool_calling_agent(llm, tools, prompt), 
+        agent=agent,
         tools=tools, 
         verbose=True, 
         return_intermediate_steps=True,
-        # CRITICAL FIX: This handles the 'list object no attribute get' error
         handle_parsing_errors=True
     )
 
@@ -248,10 +268,13 @@ if st.session_state.get('auth_status', False):
 
     with col2:
         if btn:
-            query = f"Process Loan {uid}. "
-            if use_sim: query += f"SIMULATION: Use Score {sim_score}, Status {sim_status}. Only query Name from DB."
-            else: query += "Query SQL for all data."
-            query += " Check Policies. Output Final Report."
+            query = f"Process Loan for Customer ID: {uid}. "
+            if use_sim: 
+                query += f"SIMULATION ACTIVE. Use Score {sim_score} and Status '{sim_status}'. Do NOT query credit/status tools. Only query Name."
+            else: 
+                query += "Query SQL tools for Name, Email, Nationality, Status, Score."
+            
+            query += " Check Policies using 'consult_policy_doc'. Output a Final Report Table."
             
             with st.status(f"🤖 Agent ({current_provider}) Working...", expanded=True) as status:
                 st_callback = StreamlitCallbackHandler(st.container())
@@ -262,17 +285,17 @@ if st.session_state.get('auth_status', False):
                     update_metrics(metrics_placeholder)
                     status.update(label="✅ Done", state="complete", expanded=False)
                 except Exception as e:
-                    # Fallback Logic: If Agent fails, print error clearly
-                    st.error(f"Agent Logic Error: {e}")
+                    st.error(f"Agent Error: {e}")
                     st.stop()
 
             st.success("### 📋 Final Report")
-            # Handle case where output might be in a different key due to error
             final_output = res.get('output', "Error generating report.")
             st.markdown(final_output)
             
             with st.expander("Trace"):
-                for action, obs in res.get("intermediate_steps", []):
+                # Handle ReAct agent steps format
+                steps = res.get("intermediate_steps", [])
+                for action, obs in steps:
                     st.markdown(f"**Tool:** `{action.tool}`\n**Result:** `{obs}`")
 
             if not use_sim:
@@ -282,7 +305,7 @@ if st.session_state.get('auth_status', False):
                         email = llm.invoke(f"Draft email for: {final_output}").content
                         st.text_area("Draft", value=email, height=200)
                     except:
-                        st.warning("Could not draft email due to generation error.")
+                        pass
 
 elif not st.session_state.get('auth_status', False):
     st.info("👈 Select Provider & Validate Key in Sidebar")