MusicGen is a tool developed by Facebook that uses artificial intelligence to generate music. It can create melodies and compositions in various genres, including pop, techno, and house. The tool allows users to input prompts or reference files to influence the style and mood of the generated music. MusicGen has different models of varying sizes, and it can generate music up to 30 seconds in length. It is designed to be user-friendly and can be accessed through a web interface or API.