OpenBSD pledge(2) and unveil(2) are relatively easy to create high level language bindings for, and users have already contributed several in the community, like this latest one for Ada. In base, OpenBSD only supports C/C++, however a Perl interface is also included.

https://man.openbsd.org/man3p/OpenBSD::Pledge.3p

https://man.openbsd.org/man3p/OpenBSD::Unveil.3p

A few bindings are also maintained in ports, for example GHC/Haskell (unix package) & Node.js (node-pledge) include them out of the box.

For an unofficial list of highlevel language bindings: https://gist.github.com/ligurio/f6114bd1df371047dd80ea9b8a55...