Open source models are actually _better_ at structured outputs because you can adapt them using tools like JSONFormer et al that interact with the internals of the model (https://www.reddit.com/r/LocalLLaMA/comments/17a4zlf/reliabl...). The structured outputs can be arbitrary grammars, for example, not just JSON (https://github.com/outlines-dev/outlines#using-context-free-...).
* Functionary [https://github.com/MeetKai/functionary]
* NexusRaven [https://github.com/nexusflowai/NexusRaven-V2]
* Gorilla [https://github.com/ShishirPatil/gorilla]
Could be interesting to try some of these exercises with these models.
Low latency, high quality function calling API product may be a billion dollar business in two years.