The subcommand and option object are based on Suggestion objects. Everything you can do to customise a suggestion object, you can do to a subcommand or option object.
The argument object is used to generate suggestions for an argument. For instance, the
cd command takes one argument: a folder. The arg object for
cd therefore generates suggestions for all of the folders in a user's current directory. To do this, Fig literally runs
ls in the user's terminal's current working directory, parses out all the folders, turns them into suggestion objects, then renders them.
There are 4 ways you can use argument objects to generate suggestions. These are more comprehensively outlined in