In this paper, we propose an agile model-driven development (AMDD) approach to address the challenges of automatically generating code using a large-scale language model (LLM), GPT4. AMDD models a multi-agent autonomous vehicle fleet (UVF) system using UML and integrates the Object Constraint Language (OCL) and the FIPA ontology language to reduce model ambiguity. The Java and Python codes generated using GPT4 are compatible with the JADE and PADE frameworks, respectively, and we evaluate the behavior of the generated code and the improvement of agent interaction. We compare and analyze the code complexity of models that use only OCL and models that use both OCL and FIPA ontologies, and show that ontology constraints increase the code complexity, but in a manageable level.