That’s static documentation, aka “AppleScript dictionaries”, which isn’t quite the same thing as true introspection. In combination with Script Debugger’s live

That’s static documentation, aka “AppleScript dictionaries”, which isn’t quite the same thing as true introspection. In combination with Script Debugger’s live object model browser it’s pretty powerful, but also all the more frustrating as you run into common limitations: missing or incompete details, ambiguous definitions, incorrect information, and so on. Unfortunately the original designers left Apple before the whole system was adequately specced and documented or thoroughly field-trialed, leaving both app developers and users to make blind guesses as to how things should work, and duct-tape over the shortcomings as best they can.