When designing an application using one BRE and a simple rule set this activity will be done quickly. The rule developer still needs to think about the parameters the exception management,  what are the rule part of the rule set, and how they are executed.

So for a simple unique rule set the following information needs to be designed and documented:

• Input, output parameters
• Type of data model
• Rule execution flow using a rule flow. But it is still possible with modern BRE to use re-entrant rule set, so executing a rule flow from a rule task or rule package.
• Exception management
• Inference objects like a result object which may be used to control the future execution of the caller application or the BRE.
• What are the rule part of the rule set
• What is their execution order. It is recommended to avoid using a ordering mechanism like the rule priority, but some time at a rule task level it is needed to use sorting mechanism
• When does a rule is not candidate to enter in a rule set. This is linked to the rule life cycle.