Sure, and gRPC doesn't guarantee that the server is turned on when the client makes a request. Some expectations are unreasonable.

On the other hand, if you publish one set of proto files and all clients & servers consume these artifacts, the system as a whole is more "typesafe" and reliable than if you just post swagger docs and expect all your developers to check them daily for updates.

gRPC means API changes stand a good chance of getting caught by build systems. That seems about as reasonable a definition of "type safe across systems" as can be expected.