Currently, executing /kci disableoutput without specifying anything after disableoutput will cause an 'internal error'. It would be better if it printed some error message stating that this is not the right way to use the command.

Wait... I just realized printing an error message is also wrong since disableoutput should suppress error messages...

This will be 'fixed' in KCI 12.3: running /kci disableoutput will not do anything (and won't generate any internal error).