Building a cruel game. Custom reply to 'undo'?

I’m building a humorous, cruel game about regret. I would like to disable the undo option. When playing, the game simply says that the undo function is not allowed. I sorta doubt that there is a way to do it, but can I replace this message with something custom/more comedic?

Sure you can. … doc_0.html

Yes, changing Inform’s default responses is pleasantly straightforward. Here you just want

The immediately undo rule response (A) is "your text."

Usually the best way of finding the name of the rule whose text you want to change is to use the RULES debugging command in the IDE. For some reason that doesn’t work here. But most of the rules which produce default responses are in the Standard Rules, so you can easily find the relevant one by searching there.

Actions the player can type should all be listed in the Index within the IDE under the appropriate tab also with templates for removing and changing the applicable rules.

Oh thanks jrb, that’s much easier. I was looking in the rules for it but wasn’t sure where to look.

I saw the title, and I was going to post “don’t get rid of undo! That’s so obnoxious!”

But then I saw you mention the theme of regret, and that just sounds like a genius combination. Good luck with your game!

Hanon: undoing is an exception to that; it isn’t listed in the actions index. I don’t know why.

There is no “undoing” action, because UNDO gets handled by a different part of the parser than actions.

I kind of guessed that must be the reason, but I was too lazy to open up the parser code.

Thanks everybody! And thanks jrb, for the solution.