Responsible, maybe, but Liable? I don't think so. So long as you genuinely try to do your best and don't break the law, the a company can do is fire you.
The AI agent could break the law.
But even if they don't, who is responsible for the mistakes.
What if an error leads to people getting hurt?
Well that's what c levels are supposedly for, but all they ever get is golden handshakes and parachute off to the next company to cause problems at.