Update app.py

app.py

@@ -221,13 +221,21 @@ compiled_graph = graph.compile()
 
 # ─────────────────────────── Public API  ────────────────────────────────
 
-def answer(question: str, task_id: Optional[str] = None) -> str:
-    state = AgentState(user_question=question, task_id=task_id)
-    state.add(SystemMessage(content="You are a helpful assistant."))
-    state.add(HumanMessage(content=question))
-    ans = compiled_graph.invoke(state)
-    print(f"Final answer: {ans.final_answer}")
-    return ans.final_answer or "No answer."
+def answer(question: str, *, task_id: Optional[str] = None) -> str:
+    """Run the agent and return whatever FINAL_ANSWER the graph produces."""
+    init_state = AgentState(question, task_id)
+    init_state.add(SystemMessage(content="You are a helpful assistant."))
+    init_state.add(HumanMessage(content=question))
+
+    # IMPORTANT: invoke() returns a **new** state instance (or an AddableValuesDict),
+    # not the object we pass in.  Use the returned value to fetch final_answer.
+    out_state = compiled_graph.invoke(init_state)
+
+    if isinstance(out_state, dict):        # AddableValuesDict behaves like a dict
+        return out_state.get("final_answer", "No answer.")
+    else:                                  # If future versions return the dataclass
+        return getattr(out_state, "final_answer", "No answer.")
+