The name of the type of the attribute. All legal values of this attribute will conform to this type. The semantics of the attribute. As usual with semantics in this system, this is represented by an arbitrary object. All objects of this type are expected to obey the semantics for the attribute.
Attribute descriptions contain the complete definition of an attribute.
A list of agents that can extract the attribute. How attributes are inherited A type inherits the attributes of all its supertypes. Objects of type T, therefore, must have all the attributes specifically defined for type T, plus all of the attributes defined in T's supertypes, and so on. A type does not have to redefine the attribute names that are defined in its supertypes. It may do so, however, if it wishes to define the attribute in a more constrained way, or describe the derivation differently.