stave

Prelude

Most music generators hand you a sound file. Stave hands you the score.

Hermes writes the piece as notation, so every note is on the page. You can see why the ending feels finished, hear the cello take the tune, and take the whole thing to GarageBand or MuseScore as MIDI, or print it for a real piano. You don't need to read music. The notes light up as they sound, and a line runs along the melody so your eye knows where to look.

The suite

I. Allegro · you ask

Describe what you want in plain words: "a lullaby for a rainy night", "a sea shanty for a very small boat", "something hopeful, like the first warm morning of spring". Name an instrument, a tempo or a length if you care. Hermes fills in the rest.

II. Andante · Hermes plans the form

Before any notes, Hermes decides the shape: key, meter, tempo, two or three instruments, and two to four sections with a chord for every bar. The plan appears on the staff in pencil while the notes are still being written: A · rainfall, B · deep clouds, A · rainfall.

III. Moderato · it writes, checks, and corrects itself

Each section is written in ABC notation and checked before you see it:

| Check | What fails it |
|---|---|
| Bar length | any part whose notes do not add up to the meter (6/8 needs six eighths, triplets included) |
| Range | a note a flute or a cello could not play (treble parts G3 to F6, bass parts E1 to G4) |
| Strings | a guitar chord a hand could not hold: two notes on one string, or more notes than strings |
| Syntax | stray bar lines, unclosed chord symbols, anything the engraver cannot parse |

Bars that fail go back to Hermes with the reason, once. The repaired ones are circled in the margin, checked and fixed, so you can see where it corrected itself.

IV. Cantabile · it plays

Press play or Space. Each instrument plays with its own sampled voice: music box, harp, cello, flute, guitar, strings, celesta and a dozen more. The melody lights in full blue, the accompaniment in a softer tint, and the page turns itself when the music moves to the next system. Slow it down, speed it up, or loop just the bars you selected.

V. Rubato · you change it

Click a bar, drag across several, or Shift-click, then say what you want: sadder, end on a long note, simpler bass, more like a question. Hermes rewrites only those bars, boxes them in pencil, and writes what it changed in the margin. With nothing selected, a request applies to the whole piece: slower, on strings, in A minor, make it longer.

Attacca · or ask from any chat

Stave also gives Hermes the craft itself. In any conversation, say "write me a lullaby for my daughter and put it in Stave". The agent loads the stave:compose skill (the notation rules and how to shape a short piece), writes the bars, and checks them with stave_check, the same bar-length, range and syntax checks the page runs. Then stave_open puts the piece on the Stave page. stave_open refuses music with problems and hands back the list, so the agent fixes its own bars before you ever see them. A toast tells you the piece is ready, with a button to open it.

Da capo · nothing is lost

Every change keeps a snapshot. Undo with the arrow or ⌘Z / Ctrl+Z and you are back where you were. Your pieces stay in the Pieces menu.

The score

| | |
|---|---|
| Instruments | piano, music box, celesta, vibraphone, marimba, classical guitar, acoustic guitar, electric guitar, bass guitar, harp, violin, viola, cello, double bass, strings, choir, trumpet, horn, clarinet, oboe, flute, pan flute |
| Guitar | guitar and bass guitar parts get a TAB staff under the notes, with the fret for each string. They are written an octave above how they sound, as guitar music is, and play at their real pitch. Chords use shapes a hand can hold. |
| Meters | 4/4, 3/4, 6/8, 2/4 |
| Keys | C, G, D, A, F, B♭, E♭ major; A, E, B, F♯, D, G, C minor |
| Length | 16 to 32 bars in 2 to 4 sections, longer on request |
| Export | sheet music as a PDF on A4 pages, ready to print · the score as SVG · MIDI · WAV · ABC text |

Rehearsal

Stave is a Hermes Desktop plugin.

hermes plugins install https://github.com/Adolanium/hermes-stave

Enable Stave in Capabilities → Plugins. It appears in the sidebar and as Open Stave in the command palette (⌘K).

Which model writes the music. Stave registers its own task, Stave composer, in Settings → Models. With nothing set there, Hermes uses your main model. A fast model keeps writing and edits quick; a stronger one writes better melodies.

How it stays quick. On a fast model a whole piece arrives in about five seconds and a bar edit in about one. Stave composer runs with reasoning off by default: the page's own checker catches any bar that does not add up and has Hermes repair it, so hidden thinking adds wait without adding safety. Every new section is written at the same time straight after the plan, a returning section (the second A of A B A) reuses the bars already written, and an edit sends only the bars around your selection. If a section fails, Stave asks once more; if it still fails, the bars already written are kept. To let the model think, set auxiliary.stave.reasoning_effort (for example low) in your Hermes config.

Building from source

cd desktop-src
npm ci
npm run build    # writes desktop/plugin.js
npm test

To work on the page live, link only the desktop/ folder into Hermes Desktop instead of installing the plugin (with both, the page loads twice). Every build reloads the page. The agent tools and the stave:compose skill need the full install:

ln -s "$PWD/desktop" ~/.hermes/desktop-plugins/stave

Liner notes

What Stave does on your machine, in full:

• Model calls. The page makes one stateless llm.oneshot request per step (plan, each new section, each repair, each change) through its Stave composer task. It creates no sessions.
• Agent tools. stave_check reads the piece it is given and returns problems; it touches nothing. stave_open writes one JSON file per piece to ~/.hermes/plugin-data/stave/inbox/; the page reads it through the plugin's route at /api/plugins/stave/inbox, saves the piece and deletes the file.
• Network. Playback downloads instrument samples from paulrosen.github.io/midi-js-soundfonts the first time each instrument plays. Nothing else leaves your machine except the model calls you already route through Hermes.
• Storage. Pieces, their undo history and your model choice live in the plugin's own Desktop storage. Stave writes no files unless you export one.
• Sound. Audio plays only when you press play. Stave never uses the microphone.

Coda

Stave stands on the work of others:

• abcjs by Paul Rosen (MIT) engraves the notation and plays it.
• Rough Notation by Preet Shihn (MIT) draws Hermes's pencil marks.
• Bodoni Moda and Kalam (SIL Open Font License 1.1) set the titles and the handwriting.
• The instrument samples are the FluidR3 GM soundfont, converted by midi-js-soundfonts.

Their licenses are in THIRD_PARTY_NOTICES.md. Stave itself is released under the MIT License.

README from the reviewed commit 433bcf9; it updates when the author re-pins.