About script tools
Many programs are written for specific datasets and scenarios. One of the advantages of programming is the flexibility to perform additional operations not provided by ESRI and extend the ArcGIS framework. Some programs perform a generic operation that can be used repeatedly because they use arguments to change tool parameters and behavior.
These programs rarely change and are used by many people. ArcGIS Desktop users are able to use the geoprocessing framework to create tools where program executables are used as the source. These types of tools are Script tools.