at least in computer science, this document is from CMU and tended to get circulated pretty widely, although probably not widely enough. every field ought to have something like it.
I have seen that, and it was helpful. But at least in machine learning and AI, if you want an admit into any top 10 US PhD program, you need a publication or 2 in a top tier venue, preferably first author.
In other fields and lower ranked programs, again I wish profs would be explicit (since publications might not be expected).
"So before I take you on as a new student, you should be comfortable with the foundations of the subject, which means having done the majority of the exercises in Hartshorne or my course notes, and being able to explain them on demand."
That is very explicit and sets clear expectations.
https://www.cs.cmu.edu/~harchol/gradschooltalk.pdf