docs/demo/demo-midi.md · cgcardona/muse

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# Muse MIDI Plugin — Demo

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> **Version control for music is not "track changes to audio files."**

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> **It is: version control that understands music.**

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This is the full walk-through of every music-domain capability in Muse.

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Every command below reasons about MIDI at the level of **individual notes,

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chords, bars, and dimensions** — things no VCS has ever modelled.

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Git stores music as binary blobs. Muse stores it as a **content-addressed

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graph of note events**, each with a stable identity that survives transpositions,

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rearrangements, and cross-track moves.

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## Setup

```bash

muse init --domain music

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# Add some MIDI files to muse-work/

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cp ~/compositions/melody.mid muse-work/tracks/melody.mid

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cp ~/compositions/bass.mid muse-work/tracks/bass.mid

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muse commit -m "Initial composition"

```

---

## Act I — What's in the Track?

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### `muse notes` — musical notation view

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```

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$ muse notes tracks/melody.mid

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tracks/melody.mid — 23 notes — cb4afaed

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Key signature (estimated): G major

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Bar Beat Pitch Vel Dur(beats) Channel

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──────────────────────────────────────────────────

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1 1.00 G4 80 1.00 ch 0

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1 2.00 B4 75 0.50 ch 0

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1 2.50 D5 72 0.50 ch 0

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1 3.00 G4 80 1.00 ch 0

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2 1.00 A4 78 1.00 ch 0

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2 2.00 C5 75 0.75 ch 0

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...

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23 note(s) across 8 bar(s)

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```

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**Why Git can't do this:** `git show HEAD:tracks/melody.mid` gives you a

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binary blob. `muse notes` gives you the *actual musical content* — pitch

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names, beat positions, durations, velocities — readable as sheet music,

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queryable by an agent, auditable in a code review.

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Use `--commit` to see the notes at any historical point:

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```bash

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muse notes tracks/melody.mid --commit HEAD~10

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muse notes tracks/melody.mid --bar 4 # just bar 4

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muse notes tracks/melody.mid --json # machine-readable

```

---

## Act II — See the Score

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### `muse piano-roll` — ASCII piano roll

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```

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$ muse piano-roll tracks/melody.mid --bars 1-4

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Piano roll: tracks/melody.mid — cb4afaed (bars 1–4, res=2 cells/beat)

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D5 │D5════════ │ │

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C5 │ │C5════ C5════│════

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B4 │ B4════ │ │

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A4 │ │A4════════ │

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G4 │G4════════ G4════════ │ │

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└────────────────────────┴────────────────────────┘

1 2 3 1 2 3

```

One glance tells you everything: which pitches appear, how long they sustain,

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where the bar lines fall. This is the visual interface to a content-addressed

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note graph. It works on any historical snapshot.

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```bash

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muse piano-roll tracks/melody.mid --bars 1-8

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muse piano-roll tracks/melody.mid --commit HEAD~5 --resolution 4 # sixteenth-note grid

```

---

## Act III — The Harmonic Layer

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### `muse harmony` — chord analysis and key detection

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```

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$ muse harmony tracks/melody.mid

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Harmonic analysis: tracks/melody.mid — cb4afaed

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Key signature (estimated): G major

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Total notes: 23 · Bars: 8

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Bar Chord Notes Pitch classes

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────────────────────────────────────────────────────────

1 Gmaj 4 G, B, D

2 Amin 3 A, C, E

3 Cmaj 4 C, E, G

4 D7 5 D, F#, A, C

5 Gmaj 4 G, B, D

6 Emin 3 E, G, B

7 Amin 3 A, C, E

8 Dmaj 4 D, F#, A

Pitch class distribution:

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G ████████████████████ 8 (34.8%)

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B ████████ 3 (13.0%)

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D ██████████ 4 (17.4%)

A ████████ 3 (13.0%)

C ██████ 2 ( 8.7%)

E ██ 1 ( 4.3%)

F# ██ 1 ( 4.3%)

```

**This is impossible in Git** because Git has no model of what the bytes in a

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`.mid` file mean. Muse stores every note as a typed semantic event with a

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stable content ID. `muse harmony` reads the note graph and applies music

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theory to find the implied chords — at any commit, for any track.

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For AI agents, `muse harmony` is gold: an agent composing in a key can verify

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the harmonic content of its work before committing.

---

## Act IV — The Dynamic Layer

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### `muse velocity-profile` — dynamic range analysis

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```

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$ muse velocity-profile tracks/melody.mid

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Velocity profile: tracks/melody.mid — cb4afaed

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Notes: 23 · Range: 48–96 · Mean: 78.3 · RMS: 79.1

ppp ( 1– 15) │ │ 0

pp ( 16– 31) │ │ 0

p ( 32– 47) │ │ 0

mp ( 48– 63) │████ │ 2 ( 8.7%)

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mf ( 64– 79) │████████████████████████ │ 12 (52.2%)

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f ( 80– 95) │████████████ │ 8 (34.8%)

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ff ( 96–111) │██ │ 1 ( 4.3%)

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fff (112–127) │ │ 0

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Dynamic character: mf

```

```

$ muse velocity-profile tracks/melody.mid --by-bar

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bar 1 ████████████████████████████████ avg= 80.0 (4 notes)

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bar 2 ██████████████████████████ avg= 76.0 (3 notes)

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bar 3 ████████████████████████████ avg= 78.0 (4 notes)

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bar 4 ████████████████████████████████ avg= 80.5 (5 notes)

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```

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The per-bar view reveals the dynamic arc of the composition — a crescendo

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building through bars 1–4, a release in bars 5–6. Agents can use this to

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verify that a composition has the intended emotional shape.

---

## Act V — Note-Level History

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### `muse note-log` — what changed in each commit

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```

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$ muse note-log tracks/melody.mid

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Note history: tracks/melody.mid

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Commits analysed: 12

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cb4afaed 2026-03-16 "Add bridge section" (4 changes)

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+ A4 vel=78 @beat=9.00 dur=1.00 ch 0

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+ B4 vel=75 @beat=10.00 dur=0.75 ch 0

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+ G4 vel=80 @beat=11.00 dur=1.00 ch 0

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+ D5 vel=72 @beat=12.00 dur=0.50 ch 0

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1d2e3faa 2026-03-15 "Revise verse harmony" (2 changes)

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+ D4 vel=75 @beat=5.00 dur=1.00 ch 0

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- C4 vel=72 @beat=5.00 dur=1.00 ch 0 (removed)

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a3f2c9e1 2026-03-14 "Initial composition" (14 changes)

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+ G4 vel=80 @beat=1.00 dur=1.00 ch 0

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+ B4 vel=75 @beat=2.00 dur=0.50 ch 0

...

```

**Every change expressed in musical language**, not binary diffs.

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`muse note-log` is the musical equivalent of `git log -p` — but instead of

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showing `+line` / `-line`, it shows `+note` / `-note` with pitch name, beat

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position, velocity, and duration. A composer reading this log understands

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immediately what changed between commits.

---

## Act VI — Note Attribution

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### `muse note-blame` — which commit wrote these notes?

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```

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$ muse note-blame tracks/melody.mid --bar 4

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Note attribution: tracks/melody.mid bar 4

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D5 vel=72 @beat=1.00 dur=0.50 ch 0

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F#5 vel=75 @beat=1.50 dur=0.50 ch 0

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A5 vel=78 @beat=2.00 dur=1.00 ch 0

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C6 vel=72 @beat=3.00 dur=0.50 ch 0

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A5 vel=75 @beat=3.50 dur=0.50 ch 0

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5 notes in bar 4 introduced by:

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cb4afaed 2026-03-16 alice "Add D7 arpeggiation in bar 4"

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```

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**This is strictly impossible in Git.**

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Git cannot tell you "these specific notes in bar 4 were added in commit X"

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because Git has no model of notes or bars. `muse note-blame` traces the

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exact content IDs of each note in the bar through the commit history to find

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the commit that first inserted them.

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For AI agents working collaboratively: "which agent wrote this phrase?"

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One command. One answer.

---

## Act VII — Where is the Compositional Instability?

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### `muse note-hotspots` — bar-level churn

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```

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$ muse note-hotspots --top 10

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Note churn — top 10 most-changed bars

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Commits analysed: 47

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1 tracks/melody.mid bar 8 12 changes

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2 tracks/melody.mid bar 4 9 changes

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3 tracks/bass.mid bar 8 7 changes

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4 tracks/piano.mid bar 12 5 changes

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5 tracks/melody.mid bar 16 4 changes

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High churn = compositional instability. Consider locking this section.

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```

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Bar 8 is the trouble spot. Twelve revisions. An agent or composer working

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on a large piece can use this to identify which sections are unresolved —

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the musical equivalent of `muse hotspots` for code.

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```bash

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muse note-hotspots --track tracks/melody.mid # focus on one track

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muse note-hotspots --from HEAD~20 --top 5 # last 20 commits

```

---

## Act VIII — Agent Command: Transpose

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### `muse transpose` — surgical pitch transformation

```bash

# Preview

$ muse transpose tracks/melody.mid --semitones 7 --dry-run

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[dry-run] Would transpose tracks/melody.mid +7 semitones

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Notes: 23

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Shifts: G4 → D5, B4 → F#5, D5 → A5, …

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Pitch range: D5–A6 (was G4–D6)

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No changes written (--dry-run).

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# Apply

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$ muse transpose tracks/melody.mid --semitones 7

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✅ Transposed tracks/melody.mid +7 semitones

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23 notes shifted (G4 → D5, B4 → F#5, D5 → A5, …)

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Pitch range: D5–A6 (was G4–D6)

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Run `muse status` to review, then `muse commit`

```

```bash

muse transpose tracks/bass.mid --semitones -12 # down an octave

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muse transpose tracks/melody.mid --semitones 5 # up a perfect fourth

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muse transpose tracks/melody.mid --semitones 2 --clamp # clamp to MIDI range

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```

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For AI agents, `muse transpose` is the music equivalent of `muse patch`:

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a single command that applies a well-defined musical transformation. The

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agent says "move this track up a fifth" — Muse applies it surgically and

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records the note-level delta in the next commit.

After transposing:

```bash

muse status # shows melody.mid as modified

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muse harmony tracks/melody.mid # verify the new key — still G major? No, now D major

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muse commit -m "Transpose melody up a fifth for verse 2"

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```

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The commit's structured delta records every note that changed pitch —

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a note-level diff of the entire transposition.

---

## Act IX — Agent Command: Mix

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### `muse mix` — layer two tracks into one

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```bash

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$ muse mix tracks/melody.mid tracks/harmony.mid \

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--output tracks/full.mid \

--channel-a 0 \

--channel-b 1

✅ Mixed tracks/melody.mid + tracks/harmony.mid → tracks/full.mid

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melody.mid: 23 notes (G4–D6)

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harmony.mid: 18 notes (C3–B4)

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full.mid: 41 notes (C3–D6)

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Run `muse status` to review, then `muse commit`

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```

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`muse mix` is the compositional assembly command for the AI age. An agent

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that has generated a melody and a harmony in separate tracks can combine them

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into a single performance track without a merge conflict.

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The `--channel-a` / `--channel-b` flags assign distinct MIDI channels to each

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source so instruments can be differentiated in the mixed output.

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Agent workflow for a full arrangement:

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```bash

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# Agent generates individual parts

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muse transpose tracks/violin.mid --semitones 0 # keeps content hash consistent

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muse mix tracks/violin.mid tracks/cello.mid --output tracks/strings.mid --channel-a 0 --channel-b 1

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muse mix tracks/strings.mid tracks/piano.mid --output tracks/ensemble.mid --channel-a 0 --channel-b 2

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muse commit -m "Assemble full ensemble arrangement"

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# Verify the harmonic content of the final mix

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muse harmony tracks/ensemble.mid

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muse velocity-profile tracks/ensemble.mid --by-bar

```

---

## The Full Collaborative Music Workflow

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Here's what a multi-agent music session looks like with Muse:

### Session Setup

```bash

muse init --domain music

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# Agent A starts the melody

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echo "..." | muse-generate --type melody > muse-work/tracks/melody.mid

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muse commit -m "Agent A: initial melody sketch"

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```

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### Agent B Adds Harmony

```bash

# Agent B branches

git checkout -b feat/harmony # Muse branching

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# Analyse what Agent A wrote

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muse notes tracks/melody.mid

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muse harmony tracks/melody.mid # Key: G major

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muse velocity-profile tracks/melody.mid # Dynamic: mf

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# Generate a compatible harmony

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echo "..." | muse-generate --type harmony --key "G major" > muse-work/tracks/harmony.mid

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muse commit -m "Agent B: add harmony in G major"

```

### Merge

```bash

# Three-way merge at the note level

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muse merge feat/harmony

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# If both agents touched the same MIDI file:

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# Muse splits into melodic / rhythmic / harmonic / dynamic / structural dimensions

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# Each dimension merges independently

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# Only true note-level conflicts surface as merge conflicts

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### Quality Check

```bash

# After merge, verify the full picture

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muse harmony tracks/melody.mid # still G major?

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muse note-hotspots --top 5 # which bars got the most revisions?

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muse velocity-profile tracks/melody.mid # did the dynamics survive the merge?

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muse piano-roll tracks/melody.mid --bars 1-8 # visual sanity check

```

---

## The Full Command Matrix

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| Command | What it does | Impossible in Git because… |

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|---------|-------------|---------------------------|

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| `muse notes` | Every note as musical notation | Git stores .mid as binary |

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| `muse note-log` | Note-level change history | Git log shows binary diffs |

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| `muse note-blame` | Per-bar attribution | Git blame is per line |

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| `muse harmony` | Chord analysis + key detection | Git has no MIDI model |

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| `muse piano-roll` | ASCII piano roll visualization | Git has no MIDI model |

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| `muse note-hotspots` | Bar-level churn leaderboard | Git churn is file/line-level |

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| `muse velocity-profile` | Dynamic range + histogram | Git has no MIDI model |

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| `muse transpose` | Surgical pitch transformation | Git has no musical operations |

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| `muse mix` | Combine two tracks into one | Git has no MIDI assembly |

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Plus the core VCS operations, all working at note level:

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| Command | What's different in Muse |

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|---------|-------------------------|

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| `muse commit` | Structured delta records note-level inserts/deletes |

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| `muse diff` | Shows "C4 added at beat 3.5", not "binary changed" |

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| `muse merge` | Three-way merge per dimension (melodic/harmonic/dynamic/structural) |

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| `muse show` | Displays note-level changes in musical notation |

---

## For AI Agents Creating Music

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When millions of agents are composing music in real-time, you need:

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1. **Musical reads** — `muse notes`, `muse harmony`, `muse piano-roll` return

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structured note data that agents can reason about, not binary blobs

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2. **Musical writes** — `muse transpose`, `muse mix` apply well-defined

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transformations that produce valid MIDI, with full note-level attribution

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3. **Creative intelligence** — `muse harmony` gives agents harmonic awareness;

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`muse velocity-profile` gives dynamic awareness; `muse note-hotspots` reveals

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which sections are in flux

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4. **Semantic merges** — two agents independently harmonizing the same melody

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can merge at the note level — changes to non-overlapping notes never conflict

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5. **Structured history** — every commit records a note-level structured delta;

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every note has a content ID; `muse note-blame` attributes any bar to any agent

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Muse doesn't just store your music. It understands it.

---

*Next: [Code Demo →](demo-code.md)*