The purpose of this paper is to first showcase the concept of an operation schema - a precise form of system-level operation specification and secondly show how operation schemas enhance development when they are used as a supplement to use case descriptions. An operation schema declaratively describes the effects of a system operation by pre- and postconditions using the Object Constraint Language (OCL), as defined by the Unified Modeling Language (UML). In particular, the paper highlights techniques to map use cases to operation schemas and discusses the advantages of doing so in terms of clarifying the granularity and purpose of use cases and facilitating a more systematic transition to design.