When IBM Refactoring Assistant identifies a service boundary, what must architects define to make the boundary operational?

Think of it like working hands-on with IBM mainframe systems — the answer here is 'A list of COBOL program names that must be recompiled whenever the service changes'. The service interface definition specifies the contract that callers must honor, including input and output data structures and error conditions, which later guides Java method signatures and API desi. On real mainframe exams, this concept comes up repeatedly so make sure you have it locked in.