There have been several discussions about the language server protocol here as well as an announcement of an implementation for SWI-Prolog. See e.g., Get line numbers from `xref_called/3` started by @jamesnvc. I think the state was this does not cover syntax highlighting and there is an initiative to extend the API to cover syntax highlighting but this isn’t final and there are no implementations (yet, and this is a year ago). Did the situation change?