Show HN: I trained a 125M model to autocomplete piano on-device

While LLMs (and ANNs in general) are definitely great for musical analysis (though still limited), I think they're likely overkill for the generation part, plus they tend to suffer from "creative collapse" as they prefer averages rather than exploration (which can be good or bad depending on what you want).

You started by playing a simple I - vii - I as the first sub-phrase. Then the AI started its response with a dominant 7th-chord. In the vast majority of cases I can think of from the Classical era, the AI's sub-phrase would end with a half-cadence. So, including what you played, the first two sub-phrases would look like this:

I - vii - I

V(7) - I - V

But instead, the AI took the unusual step of having a full cadence for that 2nd sub-phrase. This in music is what someone might call a "double beat" in screenwriting.

Moreover, there are no half cadences in the phrase after that. It's all full cadences in the tonic key, plus two plagal cadences over a tonic pedal there in the 2nd phrase. Each sub-phrase just extends the tonic. There are idiomatic ways to just stay in the tonic for awhile, like "Horn fifths." But this excerpt isn't idiomatic and sounds like the composer accidentally forgot to develop the harmony.

I'm going to claim that this excerpt would sound like the musical equivalent of a run-on sentence to any composer who lived from the time of J.S. Bach to Robert Schumann. And from Mahler on they'd assume you're thumbing your nose at convention.

Put another way: the kind of student who'd use this to finish a harmony exercise would end up getting the same grade they would have gotten doing it on their own.

Edit: clarifications