ShadowChecker is a tool that helps you find categories that are "shadowed", which means that they can never be activated by user input (or a srai). Most of the time, it's a result of too general use of the _ wildcard. Sometimes, a category can be unreachable because some input substitution will change the input that would normally match this category. Sraiing will work (at least in P) - this can be used to your advantage, to "protect" a category from direct activation.
Configuration is the same as for PASCALice, so read it's readme file if you need help. It is important that you place the input substitution definitions before the bot definitions in startup.xml - this will help you track down some unreachable categories. Once you sort these out however, I'd recomend turning substitution validation off, since it decreases loading time by several factors.
The compiled version of Shadow Checker 1.1: shadowcheck.compiled
The source of Shadow Checker 1.1: shadowcheck.source
Note: The Shadow Checker source is extremely badly written so I don't recommend downloading it. (Both are regular winzip archives, just change the extension to 'zip' after you download them)