This paper presents the construction of a semantic ontology aimed at automating urban land-use compatibility reports, developed through a collaborative process between a human expert and a generative artificial intelligence system. The methodology combines the regulatory expertise of an urban planning practitioner with the structural and logical capabilities of an AI assistant to model the regulatory logic of a real municipality—Algodre (Zamora, Spain). The process, executed without prior programming knowledge, was based on iterative dialogue, validation through reasoning tools, and semantic refinement in OWL using Protégé. The result is a coherent, scalable ontology capable of generating technical reports based on municipal regulations, providing a replicable and efficient model for administrative use. The article also reflects on the limits of artificial intelligence in this type of task and reinforces the importance of expert-driven knowledge structuring.