IMO debugging commands are not needed in the protocol.
Everyone can add his/her extensions.
A program is free to send output to files/pipes/network
-connecions, if it wants to. Or stderr.
But stdin/stdout are supposed to obey the standard,
which basically says: one line commands -->> responses, ended
by empty line.
BTW. I have been working on a NNGS<-->gtp gateway which
can be controlled via nngs talk/tell. It could dump it's
stderr to a NNGS channel (which could be restricted to
the operator) In gunnar's case, this is of course nonsense
-controlling a machine that is located on his desk via NNGS-
, but it is an elegant way to interact with a *playing* go-
playing-program. (it *could* be used for cheating: the turk
on the desk :-))
AvK