docker run --rm -e SERVER=mailcow.example.com -e TOKEN=000000-000000-000000-000000-000000 onestein/mailcow-cli:1.5.2 mailcow domain get
Prefix environment variables with ARG_ to pass them as argument for mailcow.
More info on how to use mailcow cli: https://pypi.org/project/python-mailcow/