This is a simple thing.
1 case: The Add-On that created the command is compatible to the system and the system just has too look it up (can be saved in a file or a variable)
2 case: The Type of command is beeing send by the server you joined, directly to the system (The system should just ask for commands and get a list with attributes, descriptions etc.)
3 case: The system just grabs the information from a user created text file that you may edit yourself etc.
Well, this was already stated in my first post, and if you would think about it, there wouldn't be a problem anyways.