An OsidRule identifies an explicit or implicit rule evaluation. An associated Rule may be available in cases where the behavior of the object can be explicitly modified using a defined rule. In many cases, an OsidObject may define specific methods to manage certain common behavioral aspects and delegate anything above and beyond what has been defined to a rule evaluation.

Rules are defined to be operable. In the case of a statement evaluation, an enabled rule overrides any evaluation to return true and a disabled rule overrides any evaluation to return false.

Rules are never required to consume or implement. They serve as a mechanism to offer a level of management not attainable in the immediate service definition. Each Rule implies evaluating a set of facts known to the service to produce a resulting beavior. Rule evaluations may also accept input data or conditions, however, OsidRules as they appear in throughout the services may or may not provide a means of supplying OsidConditions directly. In the services where an explicit OsidCondition is absent they may be masquerading as another interface such as a Proxy or an OsidQuery .