At this point in history, you have to be a bit more specific than the label "AGI," because I'd already consider language models to be above the minimum standard for "AGI."
But if you mean a program that navigates the real world at a near-human level and successfully carries out plans to perpetuate its existence, then I would expect such a program to have to work "out of the box," rather than being a pure simulacrum.
Not to say that language models can't be involved, but I'd count things like starting with a language model and then training it (or some supernetwork) to be an agent with RL as "designing it as an agent."
I wonder about a scenario where the first AI with human or superior capabilities would be nothing goal-oriented, eg a language model like GPT. Then one instance of it would be used, possibly by a random user, to make a conversational agent told to behave as a goal-oriented AI. The bot would then behave as an AGI agent with everything that implies from a safety standpoint, eg using its human user to affect the outside world.
Is this a plausible scenario for the development of AGI and the first goal-oriented AGI? Does it have any implication regarding AI safety compared to the case of an AGI designed as goal-oriented from the start?