Fable 5.2 Completes One-Shot MIDI Piano Composition Test
AI summary
A Reddit user ran one prompt in Claude Code asking Fable 5.2 to create an original fast piano piece in the style of a Chopin étude and deliver it as a MIDI file, without rerolls or edits. The reported run took 47 minutes and 7 seconds, produced 262,305 output tokens, cost $13.30 at API prices, and contained 759 notes from A0 to C8; the user also reported that Opus 5.5 took 45 minutes, cost $7.20, and wrote 651 notes on the same prompt.
In-depth insight
The test provides a concrete, if unreplicated, signal about Fable 5.2's ability to generate a large structured MIDI composition directly through code and its runtime, token, and cost profile relative to Opus 5.5.
| I run the same test on every new Claude model: one prompt in Claude Code asking for an original, fast piano piece in the style of a Chopin étude, delivered as a MIDI file. One run, no rerolls, and I don't touch the notes. Fable 5.2 at max effort: It can't hear anything. It wrote the MIDI with Python directly. For comparison, Opus 5.5 at max on the same prompt took 45 min, cost $7.20 and wrote 651 notes. What's the model and what isn't: every note, the timing, the dynamics and the pedalling are Fable's. The sound is a sampled grand (Salamander Grand Piano). The falling notes and the hands are a visualiser I built to play whatever MIDI it writes. The clip is the second half of the piece. submitted by /u/oh-keh [link] [comments] |