com.automator.runner.xpc is not allowed to send keystrokes

In Mac Automator when you want to use keystrokes in AppleScript like:

on run {input, parameters}
    tell application "System Events" to keystroke input
end run

You may got an error said "com.automator.runner.xpc is not allowed to send keystrokes".

I found a lots of questions in stackoverflow and can't get an right answer.

In short:

You have to add the application which you want to run the script to Accessibility.

For example, if you want to run the script in Chrome, then add Chrome to your Accessibility, even not need to add Automator.