On page 8 of the help menu, it says
OPTION STRICT 'DEFINT/TOOL
I tried using OPTION TOOL, and it didn't give an error.
What does it do, though?
my guess, it has to do with assigning it to the SMILE button.
It used to be part of the requirements for assigning it to the button, possibly as a switch for the file permissions. if I remember correctly, its functionality was dropped before release.
I guess it does nothing then, other than declaring that the program is a tool that can be assigned :P
I honestly have no idea, just guessing. I don't even have SB yet.
Edit: Ninja'd
OPTION TOOL tells the preproccessor to throw an error when using a COMMON DEF. It previously had the functionality Lumage described also. It might also throw on slot instructions, but I'd have to check.
Grr, this is wrong! OPTION TOOL does indeed do nothing, it's just default behavior to throw on COMMON DEF when executing from a tool slot. Sorry about that, I swear I tested this once before.