You might as well just write instructions in English in any old format, as long as it's comprehensible. Exactly as you'd do for human readers! Nothing has really changed about what constitutes good documentation. (Edit to add: my parochialism is showing there, it doesn't have to be English)
Is any of this standardization really needed? Who does it benefit, except the people who enjoy writing specs and establishing standards like this? If it really is a productivity win, it ought to be possible to run a comparison study and prove it. Even then, it might not be worthwhile in the longer run.
If we're just pattern matching to adjacent memes that might provide insight, I'd also throw "sufficiently smart compiler" into the mix. Like, yes, in theory as the compiler gets better you shouldn't have to worry about implementing random optimizations yourself, but in practice you do.
In theory, you just need normal docs and a sufficiently smart LLM and agent harness can use them, but in practice there's still benefit in organizing them a certain way to more directly manage the context window yourself.