Why is memory_step.action_output not assigned when tool_name != "final_answer" in ToolCallingAgent.step()?

[iejzh]

In the ToolCallingAgent.step() method, when tool_name == "final_answer", memory_step.action_output is assigned the value of final_answer and is returned. However, when tool_name != "final_answer", memory_step.action_output is not assigned a value.

class ToolCallingAgent(MultiStepAgent):
    def step(self, memory_step: ActionStep) -> Union[None, Any]:
        if tool_name == "final_answer":
            # ✅ action_output is assigned.
            memory_step.action_output = final_answer  
            return final_answer  
        else:
            # ❓ Why is action_output not assigned?
            memory_step.observations = updated_information  
            return None