Lisp has traditionally been a very interactive language. Yet
Common Lisp doesn't specify much with respect to interplay between
language and (user) environment. The specification does contain a very
humble Environment chapter that inclusion was supported by the
standardization commitee to signal the message that environmental
interactivity is wished for.
Editor-hints is supposed to become an interface between the
language Common Lisp and Lisp development environments.
Find the common-lisp.net project here: https://common-lisp.net/project/editor-hints/
The canonical page for this topic is Editor Hints
common-lisp.net compatibility layers