[Eony]

Y_commands is part of the YSI library, and it won't work alone, it requires many other libraries included in YSI.

EDIT :

I quickly browsed y_commands.inc, it requires the following libraries :
y_version, y_master, y_groups, y_debug, y_hooks, y_bintree, y_amx, y_playerarray, y_utils and y_natives.

So yes, you will need the whole YSI library