This paper presents the design considerations for OMNIS,1 an object management interface system. OMNIS is intended to ease the connection between an object-oriented programming language (OOPL) and an extensible object manager in order to provide support for large, persistent and shared object stores. A toolbox approach is proposed to provide general facilities for class and schema management which can be extended to address specific OOPL requirements. OMNIS is implemented in C++ and interface a graphical implemented in ET++ to define and manipulate several useful graphs.