Thanks for the feedback!
We're using clap.rs  for CLI params, which replaced some earlier code that used docopt.
To list keys, you can do an
$HOME/.hab/cache/keys. The key name that will be used to sign a package during build is typically set via the
HAB_ORIGIN environment variable.
For example, to build and sign packages for my own origin, I use:
Building always uses the latest revision of a key for an origin.
HAB_CACHE_KEY_PATH at