I did say they should document better. Customers shouldn't have to reverse engineer.

But you can't account for how all of your customers are going to use your API. It is the interface.

Like, you mentioned in another comment about a python package as an example of what they could offer. Should they offer Rust, Go, JS, etc., clients as well?

If you buy cement, you don't expect the seller to box in the area where it should be poured. They don't have the blueprints to do that correctly. They're not building your building. The trough on the cement truck is their interface. What you do with it is your job to figure out.