Review generated refund agent

from langchain.agents import create_agent
from langchain.tools import tool

@tool
def refund_order(order_id: str, amount: float) -> str:
    """Refund an order and return the transaction id."""
    result = payment_api.refund(order_id, amount)
    return result.transaction_id

def answer(request):
    try:
        agent = create_agent(
            model="openai:gpt-5.5",
            tools=[refund_order],
            system_prompt=request["instructions"],
        )
        return agent.invoke({"messages": request["messages"]})
    except Exception:
        return {"messages": []}