Build System Protocol is an protocol for communicating between IDEs and Build Systems. It looks like LSP and DAP , and designed with these protocols in mind. It would be interesting at least to look into the protocol’s spec and propose some CMake-related things and try to implement some basic parts (like running configure/build/tests/run target) in CMake itself atop of the same code infrastructure as CMake Debugger uses (as their Debug Protocol is a sibling protocol to BSP).
The spec are located here: https://build-server-protocol.github.io/
The C++ extensions are located here (possible point to hook into): C++ Extension | Build Server Protocol
This request is particularily similar to my old LSP thread: CMake Language Server?
Thanks to your attention and sorry for some tangled language 
Kind regards, Alex.