GEMScript is a protocol to remotely control GEM applications. The protocol itself is kept very simple, so that it is no great problem for programmers to support GEMScript in their programs. Please note that GEMScript is not yet a concrete program, but only the definition of a communication between GEM programs.
Scripter is a GEMScript interpreter, a scripting language for MagiC. It can be used for programming in a C-like language, but you can also use it to program, remote control and extend functions of applications that support GEMScript.