Comment by chipotle_coyote

You're absolutely right in theory. In practice... well, I've beta-tested two Mac native, non-VSCode editors that have integrated LSP support, and it's become pretty clear that a lot of language servers have only been tested against Visual Studio Code, and sometimes have rather, ah, let's say eccentric interpretations of the spec. (For instance, they may not set mode flags on responses that give guidance to the client; they may ignore initialization flags set by the client telling the server what kind of formats they can handle in responses; they may even crash if the client hasn't implemented a request they expect to be there even if the spec says supporting that is optional.)

I like that LSP has become a multi-editor standard, but I wish language server developers would test their servers against at least a few other editors, or with users of other editors reporting bugs.