LilyPond: Espresso Rag hand crossing, by claude-haiku-5.5
claude-haiku-5.5 · round 3 of 3 · seed 2$0.01SVGMP3MIDIrag.ly
rag.ly · 42 lines
\version "2.24.0"

\header {
  title = "Espresso Rag"
  subtitle = "for café piano"
  tagline = ##f
}

% Right hand: bars 1-8 and 13-16 in treble; bars 9-12 move to the bass staff (below the LH)
rhMusic = {
  \clef treble \key c \major \time 2/4 \tempo "Tempo di Rag" 4 = 116
  e'8\mf g' c'' g' | f'8 e' d' c' | e'8 g' c'' g' | d''8 c'' b' g' |
  g'8 a' b' c'' | d''4 c''8 b' | a'8 g' f' e' | d'8 f' g'4 |
  \change Staff = "lower"
  c4 g | f4 c | d4 a, | g,4 c |
  \change Staff = "upper"
  c''8 e'' g'' e'' | d''8 c'' b' g' | e''8 d'' c'' a' | c''2 \bar "|."
}

% Left hand: bars 1-8 and 13-16 in bass; bars 9-12 cross up into the treble staff (above the RH)
lhMusic = {
  \clef bass \key c \major \time 2/4
  c4\p <g c'>4 | f,4 <c a>4 | c4 <g c'>4 | g,4 <d g>4 |
  c4 <g c'>4 | g,4 <d g>4 | f,4 <c f>4 | g,4 <d g>4 |
  \change Staff = "upper"
  e'8 g' c'' g' | a'8 g' f' e' | d'8 f' a'4 | g'8 e' c'4 |
  \change Staff = "lower"
  c4 <g c'>4 | g,4 <d g>4 | a,4 <e a>4 | c,2 \bar "|."
}

\score {
  \new PianoStaff <<
    \new Staff = "upper" <<
      \new Voice = "rh" { \rhMusic }
    >>
    \new Staff = "lower" <<
      \new Voice = "lh" { \lhMusic }
    >>
  >>
  \layout { }
}
round 1 of 3
Espresso Rag, with the left hand crossing over, by Claude Haiku 5.5, the render after round 1
123What the model saw after each round. The picture above is the round that was scored, round 3.
gallery/Espresso Rag, with the left hand crossing over/Claude Haiku 5.5, run 2

Espresso Rag, with the left hand crossing over: Claude Haiku 5.5

modelanthropic/claude-haiku-5.5tasklilypond-espresso-rag@v1, checks c1, harness h1date2026-10-08rounds3 of 8 allowed, 12 minutes on the clockcost$0.0118thinkingmediumtokens43,123 in, 20,876 out, of which 18,340 reasoningtime1 min 59 sfailedCrossing marked: incomplete, annotation missing, minor, 0 of 2 marks, the crossing and its release, its note said nothing was wrong
Piano staffdecided by a number, from the filepass
Sixteen barsdecided by a number, from the filepass
Left hand crossesdecided by a number, from the filepass
Right hand keeps goingdecided by a number, from the filepass
Crossing markeddecided by a number, from the filefail
Stems apartdecided by a number, from the filepass

There is no post about this one, since only some results need one, so the picture, the source and the scoring are here instead.

its other runs
Espresso Rag, with the left hand crossing over, by Claude Haiku 5.5, run 1run 1 · 1r · $0.0122Espresso Rag, with the left hand crossing over, by Claude Haiku 5.5, run 3run 3 · 2r · $0.0088
same prompt, other modelsall 12 runs on Espresso Rag, with the left hand crossing over →
the prompt it was given
Write, in LilyPond, 16 bars of café piano music called "Espresso Rag" in which the left hand crosses over the right hand for bars 9 to 12.
Frozen at v1. This model got this and nothing else.
ground truth

LilyPond's own record of every note: its hand, staff, bar, pitch and stem, read while the file is engraved. A voice belongs to the hand whose staff it starts on, unless its notes are labelled with a hand's name. The script was written after hearing Sol's and Pareto's runs, so Luna was its first fair test. How good the music sounds is rated by ear. How it is scored, and this run's files on GitHub.