The MSSP specification is available at:

http://tintin.sourceforge.net/mssp

In order to announce MSSP support you need to send IAC WILL TELOPT_MSSP to
each new connection, unless you call announce_support() which will announce
all supported protocols as defined in tables.c.

The next step is to update the process_do_mssp() function in telopt.c and
change the various fields so they match your MUD.MSSP data with your MUD's
information.

If your MUD doesn't provide you with global information about the number of
rooms and other such data, it's suggested to incorporate MTH's mud_data
structure.