Type four words and get a full style prompt back — instruments, arrangement, production character and a tempo. Instant, and four credits a run.
What it does
Music models respond to some words far more than others. Naming instruments, giving a tempo as a number and describing production character all change the output substantially. Piling up adjectives mostly does not. The gap between a prompt that works and one that does not is usually knowledge of that vocabulary rather than effort.
This closes that gap. Type the rough idea — "dark synthwave with a live drummer" — and what comes back names the oscillators, describes the drum treatment, mentions the tape saturation and gives a BPM. It reads like something written by someone who knows what the model reacts to, because it is generated by the same family of models.
The result belongs in the style field rather than in the song description. Those are two different inputs doing two different jobs: one says what the track sounds like, the other says what it is about. Mixing them is the single most common reason a generation ignores half of what you asked for.

How it works
A few words in, a paragraph out, immediately.
A genre and one distinguishing feature is plenty. "Bossa nova but melancholy" or "trap with orchestral strings" both work.
The interesting part is what you did not say — the instruments it named, the tempo it chose, the production terms it used. That is the vocabulary worth learning.
Not the description field. Keep the description for what the song is about.
What you get
Not longer for the sake of it — longer in the specific dimensions the model responds to. Length alone changes nothing; naming an instrument does.
dark synthwave with a live drummer
instrumentation, arrangement, mix character and a tempo — the things the model acts on
Instruments, arrangement, production character and tempo. Get those into a prompt and the rest is decoration.
The style field and the description field are read differently. An expanded sound description in the wrong one is largely wasted.
Naming an artist does not get you their sound. Listing ten instruments gets you a muddy arrangement. A paragraph of adjectives does almost nothing at all.
Who uses it
The most common case. You can hear it; you just cannot name the drum treatment.
Usually a prompt with no instruments and no tempo in it. Expanding it fixes both.
Expand five prompts and read what they have in common. That is the whole lesson.
Ask for one you have never made and see what it says the ingredients are.
Expand the same idea twice and you get two different specific readings of it.
A specific description of a sound is useful to a human musician too.
FAQ
The style field, not the song description. The style field is where the model expects sound and production information; the description is for what the song is about. Putting an expanded style paragraph in the description is why a lot of prompts appear to be ignored.
Four credits a run — a small fraction of what generating a song costs, because it returns text rather than audio. A new account has enough for around fifty runs. It is metered rather than free on purpose: an unmetered endpoint that costs real money on every call is one script away from a very large bill.
Both. The site generates music with the same family of models, so an expanded prompt works here directly — and nothing stops you using it elsewhere. The vocabulary is not proprietary.
No, and this is worth being clear about. What helps is specificity in the right dimensions — instruments, tempo, production. Length in adjectives does nothing, and naming ten instruments produces a crowded arrangement rather than a rich one. Expanded prompts are better because of what they contain, not how long they are.
You can type it, and what comes back will be a description of the genre and era rather than that artist. That is the intended behaviour. The useful move is to describe what you actually like about them — the drum sound, the vocal treatment, the era — which works well.
Each expansion is a fresh interpretation. Run it twice and you get two specific readings of the same vague idea, which is a quick way to explore — sometimes the second one describes what you meant better than your own sentence did.
No — this is about the sound. Lyrics are a separate tool on the lyrics generator page, at the same price.
Yes, and they are underused. An expanded prompt says what you want; negative tags say what keeps turning up that you do not. "Female vocal" or "distorted guitar" in the negative field is often the fastest fix when a generation is nearly right.
Up to 200 characters. Short is fine — the whole point is that you type four words and it supplies the rest.
Yes, and arguably more, since there are no lyrics carrying any of the meaning. Everything the listener gets comes from the arrangement, which is exactly what the style field describes.

Four words in, a usable style prompt out. Four credits a run.