This is a simple AppleScript that can be used with Automator to toggle Mirror Display option using a keyboard shortcut.

This can be useful if you have multiple displays and want to switch between Mirror Display option and default extended display option with a single keyboard shortcut.

Normally the same task can be done by using the existing CMD + fn + F1 keyboard shortcut. However, it doesn't set "Optimize for:" option to the Built-in Display. This script does that.

1. Create a new Application with the Script using the Automator App.
2. Give the Application accessibility cabability from System Preferences -> Security & Privacy -> Accessibility.
3. Create a new Quick Action from Automator to launch the Application.
4. Finally from System Preferences -> Keyboard -> Shortcuts -> Services -> general, activate the Quick Action with the keyboard shortcut of your choice.

1. Better Error Handling.
2. Revert back to the old active state of System Preferences if it was already running.
3. Give time limit to repeat until blocks.

The toggle-mirror-display script is licensed under the MIT license.