At the heart of Rules.Toolset© is the Modeler, which is a service that evaluates input values compared to a domain-specific model and produces a set of output values. The model can be thought as a comprehensive, structured description of a knowledge domain. This description consists mainly of formulas, which are the means to express the rules of the domain and variables, which are used to express input values.
The Rules Toolset© development team assessed a variety of solutions and adopted a modelling approach to improve the efficiency of product (report) development. An XML-based language that has been developed exclusively for the Rules Toolset© solution is used to express models that govern all of the complex interactions among genetic variations, lifestyle characteristics and biomedical data. The syntax of this XML language allows greater freedom to express logic and rules using concepts and multiple types of formulas. The XML language specification permits concepts to be nested and includes formulas using other formulas as operands. Using the XML language to build the logic allows the definition of models in the form of XML files.