I also prefer `direnv`. I am not entirely sure how `asdf` actually works; `direnv` is pretty straightforward: it hooks into the shell and modifies environment v

I also prefer `direnv`. I am not entirely sure how `asdf` actually works; `direnv` is pretty straightforward: it hooks into the shell and modifies environment variables. (`PATH`, but also tool-specific variables if required.) So it's pretty easy to debug or replicate by hand if necessary. It can't actually install different versions though (looks like `asdf` can?), which is somewhat inconvenient.