Update app.py

app.py

@@ -143,6 +143,12 @@ def reasoning_node(state: AgentState) -> AgentState:
     if not token:
         raise ValueError("Hugging Face API token not found in environment variables")
     
+    history = state["history"]
+
+    # FIX: Add a HumanMessage if the last message is not one
+    if not isinstance(history[-1], HumanMessage):
+        raise ValueError("Last message in history must be a HumanMessage")
+    
     # Create the underlying LLM model
     llm = HuggingFaceHub(
         repo_id="HuggingFaceH4/zephyr-7b-beta",