This paper proposes the CFE framework--Composition, Feedback, and Evolution--and presents an interactive music composition system. The system composes short, manageable pieces of music by interacting with users. The most important features of the system include creating customized music according to the user preference and providing the facilities specifically designed for producing large amounts of music. We present the structure as well as the implementation of the system and the auxiliary functionalities that enhance the system. We also introduce the auto-feedback test with which we verify and evaluate the interactive music composition system. Categories and Subject Descriptors H.5.5 [Information Interfaces and Presentation]: Sound and Music Computing--Methodologies and techniques General Terms Design Keywords Evolutionary computation, real-world application, interactive music composition, auto-feedback test