The present invention provides a method and system for registering rules for attributes of an entity with an entity validation and inference unit. The entity validation and inference unit can further validate input values for an entity and/or infer attributes of an entity using the associated registered rules. The entity validation and inference unit can also provide information regarding attributes, relations, and behaviors of an entity using the associated registered rules in response to a query. The present invention also provides a mechanism for a user to query an entity or the entity validation and inference unit regarding valid values for an entity. The mechanism also allows the user to query the registered rule associated with the entity.