def _render_messages(state: AgentState) -> None:
    if not state.get("messages"):
        with st.chat_message("assistant"):
            st.write(
                "Hi! I can help you book house or couch cleaning. "
                "Tell me what you need, including the size and service address."
            )
        return

    for message in state["messages"]:
        if isinstance(message, HumanMessage):
            role = "user"
        elif isinstance(message, AIMessage):
            role = "assistant"
        else:
            continue
        with st.chat_message(role):
            st.write(str(message.content))