https://click.palletsprojects.com/en/8.1.x/shell-completion/

This works for zsh:

eval "$(_SQLITE_UTILS_COMPLETE=zsh_source sqlite-utils)"

This will probably work for bash:

eval "$(_SQLITE_UTILS_COMPLETE=bash_source sqlite-utils)"

Need to add this to the installation docs here: https://sqlite-utils.datasette.io/en/stable/installation.html - along with the pattern for adding that to .zshrc or whatever.