init

app.py

@@ -24,7 +24,8 @@ if "retriever" not in st.session_state:
     st.session_state.retriever = None
 if "vector_store" not in st.session_state:
     st.session_state.vector_store = None
-workflow = None
+if "workflow" not in st.session_state:
+    st.session_state.workflow = None
 
 
 st.set_page_config(
@@ -95,8 +96,12 @@ if prompt := st.chat_input("Ask a question about your document"):
                     ]
                 }
 
-                response = workflow.invoke(inputs)
-                final_response = response["messages"][-1].content
+                # Generate response using workflow
+                if st.session_state.workflow is not None:
+                    response = st.session_state.workflow.invoke(inputs)
+                    final_response = response["messages"][-1].content
+                else:
+                    final_response = "Please upload a PDF document first."
 
         st.markdown(final_response)
         st.session_state.messages.append({"role": "assistant", "content": final_response})