Most primitive language for LSP?

cross-posted from: https://programming.dev/post/1245230

Hi, what is the most primitive programming language (esolangs included) that you can think of or make up that could still be reasonably well^1^ supported by a language server (or similar piece of software)?

1 We have to draw a line somewhere, so I'd figure capabilities

• highlight semantic errors
• renaming stuff safely, that is:
  • without confirmation
  • without evaluating parts of the code
• proper completion (not just best guess)
• go to definition/show use

I appreciate your answers!