Why not have it research Svelte 5 syntax and write itself a syntax & function call checking tool, then put that in Husky / pre-commit so it gets run all the time.

Then it will have the signal that is in your head, and you’ll never again need to tell it to use Svelte 5.

As you see more “wrong” usage, have it add those to the checker, and the checker will keep getting better over time.