2026. A Python-based toolbox for music generation and practice developed by Roberto Olmi and Marco Bittelli. GeCo-Tools is a growing collection of interactive web applications for musicians, composers, educators and students. It provides practical tools for exploring harmony, serial music, generating chord progressions and voicings, analysing scales and musical structures, and supporting composition, improvisation and instrumental practice. Each application combines music theory with modern web technologies to offer an intuitive environment for experimentation, learning and creative discovery.