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.
It’s also related to attention — invoking a skill “now” means that the model has all the relevant information fresh in context, you’ll have much better results.
What I’m doing myself is write skills that invoke Python scripts that “inject” prompts. This way you can set up multi-turn workflows for eg codebase analysis, deep thinking, root cause analysis, etc.
Works very well.