Mistype a command and zcomplete works out which one you meant from the commands you usually run, then offers to run it with your arguments. Or runs it without asking, if you set it that way.
$ mkd build
zcomplete: run mkdir instead of 'mkd'? [Y/n] y
$ cargo tset
error: no such command: `tset`
zcomplete: run cargo test? [Y/n] y
Works on bash, zsh, and fish. No process on the happy path.