Beat for macOS contains a CLI (command line interface) tool, which for now is limited to creating PDF files.
You can find the tool in the app bundle, Beat.app/Contents/MacOS/beat-cli. To access the command anywhere, create a symlink to a folder which is defined in your paths.
Basic usage
beat-cli pdf [sourceFile] [targetFile] [options]
For example:
beat-cli pdf ./MyScreenplay.fountain ./MyScreenplay.pdf
Full documentation is found in the CLI tool itself. Type beat-cli pdf --help to see all available options and flags.
In the future, the tool will support running plugin scripts without the actual application host. This will allow all sorts of automated processes to be done on you screenplay, even on cloud files.