That's great, but then how do we know that the grammar matches what we want to do - with some sort of test?

A codegrammar?

Design requirements are what it should do, not how it does it.

That's why you must negotiate or clarify what is being asked. Once it has been accepted, it is not ambiguous anymore as long as you respect it.

I'm a systems analyst, or in agile terminology "a designer" as I'm responsible for "design artifacts"

Our designs are usually unambiguous

And NOT yet another front page written in ReactJS.

I knew it, i should've asked for assembly