This work presents a new model for the description of rules for adaptive software applications. The model establishes a set of rule properties (e.g. atomicity, compositionality according to 4 defined combinations or restrictions of these combinations) which imply a set of advantages such as reusability, interoperability or improvements in the authoring process.Some of these advantages are the same as from traditional software engineering but made stronger with the consideration of a service oriented Internet in which rules can be composed from different Internet sources according to the rule restrictions combinations