A random prompt button looks simple, but it can define the taste of the whole product. If it returns the same three cafe ideas, users feel the service is shallow. If it returns chaotic genre soup, the model produces confused tracks. The goal is controlled variety.
A useful prompt database should separate dimensions: use case, mood, genre family, instrument palette, rhythm density, texture, loop behavior, and avoid-list. Combining these dimensions creates many outcomes without writing thousands of fixed prompts by hand. The system can produce variety while staying inside musically reasonable boundaries.
Instrumental and vocal modes should not share the same prompt logic. Instrumental prompts should focus on arrangement, space, loop, and non-distracting texture. Vocal prompts need theme, language, lyrical structure, hook design, and a clear instruction not to sing the production tags. Mixing those modes creates exactly the kind of bad lyrics users complain about.
The database should also learn. If lo-fi, smooth jazz, and chillhop perform well, the system can create more branches around those styles. If K-pop EDM or G-funk fails under a certain model, it can add more specific instrument and rhythm language or reduce that style's weight until it improves.
Randomness is valuable only when it produces usable surprise. BGMFREE should treat random recommendations as a curated music design system, not a dice roll attached to a text box.