Put in where the track is right now — mood, key, BPM, vibe. Get a compelling change for the next section: a key move, a bass move, or a vibe move that keeps the thread of the tune but lands as a new section. Add an intent to steer it.
This section
One key, two keys, a mode, or "atonal".
Mood + key is enough to start
The move
Other angles
Suggestions come from a built-in harmonic engine — circle-of-fifths relationships, modal brightness, chromatic mediants and voice-leading — weighted by your intent. It runs entirely in the page, so it works offline and on your own site with no API key. Treat it as a starting prompt, not a rule. Trust your ears.