James Aspnes's TinyMUD featured a very elegant interface for users 
customize and extend the MUD from the inside. Although the state of
the art has gone beyond TinyMUD (and MUDs in general), the command 
set is still a useful reference.

These documents on the original TinyMUD are in danger of disappeari
from the Internet, so I'm saving copies here.

(to nexus)

YOU SEE HERE:

These docs were written with the help of Three, who wrote probably the best

TinyMUD Command Dictionary, World Encyclopedia, and Examples

tinymud.pdf

tinymud.ps

A brief guide to TinyMUD

(to nexus)

Logic is a little bird, sitting in a tree; that smells *_____a