Even if you have 10 different ways of describing plugins all by different teams, you're not writing declarative code for each one, you're throwing them to the LLM all the same and saying "you figure it out," and it does.
Finetuning a model for certain schemas (as the author at one point suggests) should be entirely unnecessary, given my experience. You just need access to a model more at par with gpt-3.5-turbo, which we'll surely see in open source in no time!