Specify Relevant Business Capabilities
You may have noticed that the example descriptions in What Is A Behaviour Specification Description? explicitly specify the usage of an "address validation service". In that example, an "address validation service" is a well-known, documented capability that exists within the business. The example descriptions are subtly referring to the logical capability that exists within the business — a service to validate an address — and not the physical, technical implementation of the service, nor the specific technical name of that physical service.