Pay attention to the architecture of VS Code. While electron delivers questionable user experience, the internal architecture has a lot of wisdom in it. Do orient editor’s API around presentation-agnostic high-level features. Basic IDE functionality should be a first-class extension point, it shouldn’t be re-invented by every plugin’s author. In particular, add assist/code action/lightbulb as a first-class UX concept already. It’s the single most important UX innovation of IDEs, which is very old at this point. Its outright ridiculous that this isn’t a standard interface across all editors.
But don’t make LSP itself a first class concept. Surprising as it might seem, VS Code knows nothing about LSP. It just provides a bunch of extension points without caring the least how they are implemented. LSP implementation then is just a library, which is used by language-specific plugins. E.g., Rust and C++ extensions for VS Code do not share the same LSP implementation at runtime, there are two copies of LSP library in memory!
