You don’t need to cover every parameter and use case of every command. You just need to cover the most common use cases and give them priority over the more eso

You don’t need to cover every parameter and use case of every command. You just need to cover the most common use cases and give them priority over the more esoteric flags. So beginners get help but power users can still use the shell. I say “just” but obvious even that is still a big task. As for covering every flag for every tool, some shells already parse man pages and —-help output to provide meaningful autocompletions automatically. Murex does this (https://murex.rocks https://murex.rocks) as does fish (https://fishshell.com https://fishshell.com)