Most agents need some form of formal instructions tied with designing prompts - which are a mix between formal programming and natural language. This needs a slightly different skill set from the traditional backend engineer or services engineer. This is not a ML or data role either.
Rather than just a prompt engineer, the case for which could be made like a specialist designer - this role maybe more akin to a full-stack developer role who knows how to align LLM's or Diffusion models towards a multi-step goal.