For cases like this, there are several ways of doing. I think the simplest one is to assert the values you want to reason over as facts. So, pretent the user is supposed to enter a "threshold" value for your rule. Assert the threshold the user entered as a Threshold fact: rule "somerule" when Threshold( $threshold : value ) foo : Foo ( level > $threshold ) then // do something end So, in this case you don't need to generate any rule on the fly (that is much heavier than simply asserting/modifying/retracting facts). Just keep managing the user parameters as facts. This parameters can come from user interface, databases, configuration files, etc... There are other ways, but they require a lot more care (using globals for instance). So, I strongly recomend the above for the case you described. []s Edson seeker wrote: -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3124-6000 Mobile: +55 11 9218-4151 JBoss, a division of Red Hat @ www.jboss.com