The best way to "debug" is to just connect whatever signal you want to see to an outlet. You could temporarily add an extra outlet to the gen patcher for this purpose.

Unfortunately this can be extremely tedious, especially with complex [codebox]s and such. Some sort of print function would be a godsend. Obviously it would need some sort of limits on it to avoid overflowing the Max window, like only printing out the first x samples worth of values that get sent to it, x being an argument you could set.