Library development requires a wide variety of information independent of cells such as Process-Voltage-Temperature (PVT) corners and CAD tools' information. With technology scaling, such information increases continuously. Dealing with the specifications containing this information is therefore a crucial issue for library providers due to the great impact of the specification reliability on the quality of library. However, its definition is manually carried out depending upon the expertise of specification developers. It may lead to some specification problems such as inconsistency and incompleteness. In this paper, a specification language based on eXtensible Markup Language (XML) is used to encapsulate all cell-independent information for library development. We propose a reference-based specification tool to achieve reliable specifications. The experimental results show that it permits to efficiently and rapidly create complete and consistent specifications for library development in comparison to the manual method.