My TokenOperator package includes that extra level abstraction that you might be looking for. I like the resulting clean interfaces, but it didn’t really improve my day-to-day clarity and maintenance of the codebase. Here are some goals of that project that might jibe with a library you use or something you write.
I would only note that the aforementioned package-less pattern is, at its core, just a context function that takes an optional argument. That argument is expected to be a function (anonymous or otherwise) that takes one argument (an Ecto query or otherwise). You can do anything in that function. In practice, it has always been an Ecto query for me, but there is nothing precluding you from injecting something else there, to the extent it provides you with an interface you like.
