Geoprocessing tools provide an integrated and familiar experience for analysts to perform data management and spatial analysis in ArcGIS. By creating a geoprocessing tool, others can reuse your methods and workflows with their own data without requiring them to learn or use code. This session will show you how to create and design geoprocessing tools, choose appropriate parameters, write custom validation routines to fine-tune the user experience, and author help so the tool can be used correctly by others. Approaches for debugging, error handling and messaging will also be covered.