The potential of generative AI has been recently demonstrated through different applications. The open government and smart city initiatives can leverage this potential to produce innovations that improve government workflows and the lives of citizens. This commentary makes the case for a description language enabling the structured documentation of these upcoming innovations. The description language would facilitate the communication between governments, citizens and innovators. The key elements of the description language are briefly sketched and its usefulness is shown by the generation of ideas for GenAI tools related to interactive maps in cities.