If you don’t pass any file to ansible-later it will review all files including sub-directories in the current working directory (hidden files and folders are excluded by default). Otherwise you can pass a space delimited list of files to review. You can also pass glob patterns to ansible-later:
ansible-later will review inventory files, role files, python code (modules, plugins) and playbooks. The goal is that each file that changes in a changeset should be reviewable simply by passing those files as the arguments to ansible-later.