Files with the .ACTION extension, written in the Mac OS script language, contain a description of actions for execution in connection to an automatized process, saved as a file with the .WORFKLOW extension.

Automator, an app that uses the ACTION format, helps automatize processes in the Mac OS X system. Files supported by the app can be divided into system files, user files, and admin files, and are available to all or some users in separately located catalogs in the Library.