@setfield()

The @setfield() function will set a specific field (description, 
success, odrop, va, etc.) on a specific thing. That thing must
be owned by the player who owns the program. The first argument 
is a number, representing the dbref of the thing. The second is 
a string, representing the name of the field, and the third is 
also a string, representing the value. The name of the field will
automatically be converted to lower case.
(Note: Not all fields can be set using this command. Particularly, you
cannot set any field with a space in its name.)

Examples:
@setfield("204", "description", "The spellbook is too soggy too read.")
@setfield("1092", "vc", "100")