Photoshop supports external automation through scripting. In Windows, you can use scripting languages that support COM automation, such as VB Script. In macOS, you can use languages such as AppleScript that allow you to send Apple events. These languages are not cross-platform but can control multiple applications such as Adobe Photoshop, Adobe Illustrator, and Microsoft Office. In macOS, you can also use Apple’s Photoshop Actions for Automator to control tasks in Photoshop.
You can also use JavaScript on either platform. JavaScript support lets you write Photoshop scripts that run on either Windows or macOS.