If the context is helpful - when you add a tap listed on the hub it pulls the settings down into your

plugins

directory as a lock file, then meltano knows to reference those when doing something like

meltano config tap-csv list

. For custom plugins that settings lock file doesnt exist so meltano doesnt know the available settings, so it just falls back to whats set in your meltano.yml. In the future a nice feature would be to have it fall back to calling the tap's

--about

command (assuming its SDK based) to get available settings.