We describe the programming language FOBS-X (Extensible FOBS). FOBS-X is interpreted, and is intended as a universal scripting language. One of the more interesting features of FOBS-X is its ability to be extended, allowing it to be adopted to new scripting environments. FOBS-x is structured as a core language that is parsed by the interpreter, and an extended language that is translated to the core by macro expansion. The syntax of the language can easily be modified by writing new macros. The library for FOBS-X is reconfigurable, allowing the semantics of the language to be modified, and adapted to facilitate the interaction with interfaces to new scripting environments. This paper focuses on the tools used for the semantic extension of the language. A tool called FEDELE has been developed, allowing the user to add library modules to the FOBS-X library. In this way the semantics of the language can be enhanced, and the language can be adapted.