By asking the user to explain what they want whenever there's ambiguity.
Plus all the other things that software engineers generally have not learned to a professional level even if they picked up the basics on the job by osmosis, because figuring out the customer's needs (and what they'll pay you for which may be different) is the job of a business analyst, a PM, or a UX researcher, and those are different skills and two of them may come with a Business Informatics degree rather than a CompSci one.
LLMs can be "eh, better than nothing" at many things, not just code.
And when an LLM runs up costs for a small company by getting them to lease a bunch of infrastructure they don't need, who can they sue? A contractor or advisor you can't hold liable is just a liability.
> And when an LLM runs up costs for a small company by getting them to lease a bunch of infrastructure they don't need, who can they sue?
This question is completely disconnected from reality. If you try to sue a human for proposing something more complex than what you need you will waste a lot of money and then lose the lawsuit.
Also the annual cost of too much small company infrastructure is less than the cost of even a single good human engineer.
Same person they'd sue if they used any other power tool themselves and it didn't work out right.
Plus, this is software "Engineering" we're talking about, which famously gets scare quotes in comparison to all the other forms of engineering because unlike them we don't have as standard things like professional liability insurance to cover serious professional errors of judgment the way someone who signs off on a bridge that collapses would have.