Don't forget to add that table to the list of other commands at ChatterBox FAQ#chatterbot. And, if you don't want to duplicate that help information on chatterbot's user-page, could you at least include that link to the FAQ from the user-page?

Since I was reminded of the private interface, I did verify that I can roll a die via /msg chatterbot d6 as well.

And why not allow !d4 or !d8 or !d100 or even stranger dice... That is, do a pattern match for m/!d(\d+)/ and roll the appropriate $1-sided die. Not all conflicts can be resolved with 2, 6, or 20 choices. ;-) A !d1 would definitely require your <!-- id -->. And I'm curious what you'd choose to reply to a !d0