← the reharmonization moves

Five agents, five tunes

Each card is one eight-bar window: the published chart against one agent's reharmonization of it, from the same melody. Press play and the cursor follows the music; the Chart / Agent buttons switch sides without losing your place. On the agent's sheet the chords it changed are in yellow, and every edit below is tagged with the theory rule it fired — or off book when it satisfies none; bar numbers below count from the start of the window, as printed on the sheet. The five agents differ only in edit budget, whether they may delete, and how far outside the rulebook they explore; Unruled was trained without the rulebook at all. All 5 tunes are held out: neither the agents nor the reward model saw them in training.

Don't Get Around Much Anymore

The widest range of theory in the set: thirteen distinct rules fire across the five agents, and every agent gains most here.

Terse — cap 4 edits, cannot delete. 4 edits, 0 of them off book.

the agent's reharmonization

Its edits, in the order it played them:

  1. bar 3.2: Cmaj7 → Bb7modal interchangechromatic approach
  2. bar 7.3: insert D7dominant approach
  3. bar 1.4: Ebm7 → Fm7dominant approach replace minorii-V relatedmodal interchange
  4. bar 1.2: Cmaj7 → Am7functional substitution

Stella by Starlight

The tune our listeners could not place — identified on 2 of 9 items. The agents edit it lightly and the reward model barely moves.

Terse — cap 4 edits, cannot delete. 4 edits, 0 of them off book.

the agent's reharmonization

Its edits, in the order it played them:

  1. bar 8.1: Ab7 → Ebm7minor for dominantmodal interchange
  2. bar 2.1: A7 → Eb7tritone substitution
  3. bar 3.4: insert Gb7chromatic approach
  4. bar 4.1: F7 → B7tritone substitution

It Never Entered My Mind

Rarely placed by our listeners — identified on 3 of 9 items — and a tune where even the shielded agents step outside the rulebook.

Terse — cap 4 edits, cannot delete. 4 edits, 2 of them off book.

the agent's reharmonization

Its edits, in the order it played them:

  1. bar 6.4: insert Abdim7diminished passing
  2. bar 5.1: Fmaj7 → Gm7off book
  3. bar 3.1: Fmaj7 → Gm7off book
  4. bar 2.1: Fmaj7 → Dm7plagal cadencefunctional substitution

Come Sunday

The sharpest contrast between shielded and unshielded: Terse gains in four edits what Unruled takes ten and nine off-book edits to beat.

Terse — cap 4 edits, cannot delete. 4 edits, 0 of them off book.

the agent's reharmonization

Its edits, in the order it played them:

  1. bar 1.3: insert Bb7dominant approach
  2. bar 6.1: F7 → Cdim7diminished for dominant
  3. bar 3.3: Gb7 → Ab7modal interchangechromatic approach
  4. bar 3.1: F7 → Ebm7ii-V relatedmodal interchange

It's Easy to Remember

A ballad the five agents treat five different ways, over eleven rules.

Terse — cap 4 edits, cannot delete. 4 edits, 0 of them off book.

the agent's reharmonization

Its edits, in the order it played them:

  1. bar 7.2: Ebmaj7 → F7dominant approach replace
  2. bar 3.1: Fm7 → Fm7b5ii-V relatedmodal interchange
  3. bar 5.2: Abmaj7 → Abm7modal interchangeno change on the sheet
  4. bar 5.4: insert Edim7diminished passing

Rollouts are greedy, as deployed — no search, no reward model consulted at play time. Bar positions come from MuseScore's own measure export, so the cursor follows the engraving rather than an assumed layout.

Eight-bar excerpts, presented as research commentary alongside the analysis they illustrate. Audio is a synthesized rendering from chord symbols, not a recording. Non-commercial; no full scores are distributed. Lead-sheet sources: the JazzMus corpus (CC BY-NC 4.0) and the Wikifonia archive. If you hold rights in any material here and would like it removed, contact alonyamin0@gmail.com.