The key capability that Bosque has for API specs is the ability to provide pre/post conditions with arbitrary expressions. This is particularly useful once you can do temporal conditions involving other API calls (as discussed in the blog post and part of the 2.0 push).
Bosque also has a number of other niceties[0] -- like ReDOS free pattern regex checking, newtype support for primitives, support for more primitives than JSON (RAML) such as Char vs. Unicode strings, UUIDs, and ensures unambiguous (parsable) representations.
Also the spec and implementation are very much not proprietary. Everything is MIT licensed and is being developed in the open by our group at the U. of Kentucky.
Bosque also has a number of other niceties[0] -- like ReDOS free pattern regex checking, newtype support for primitives, support for more primitives than JSON (RAML) such as Char vs. Unicode strings, UUIDs, and ensures unambiguous (parsable) representations.
Also the spec and implementation are very much not proprietary. Everything is MIT licensed and is being developed in the open by our group at the U. of Kentucky.
[0] https://dl.acm.org/doi/pdf/10.1145/3689492.3690054