Compose and stage Analog Rytm pattern and kit changes from a library of dumps, then export a fresh whole-project or differential .syx. Source files stay read-only; the working destination is changed only in memory, and every run writes a new file.

Samples must already live on the Rytm +Drive. The builder only copies 16-byte fingerprints so restored kits bind to those files. There is no USB/MIDI send.

Firmware target: AR 1.70 / v5 object sizes (same as Johnny’s MK1 dumps).

This branch (cursor/rytm-mac-app-0afb) is the working universal Mac wrap (Intel + Apple Silicon).

git clone -b cursor/rytm-mac-app-0afb https://github.com/stampman3000-jpg/rytm-builder.git
cd rytm-builder

Already-built .app: double-click to open. The first time, right-click the app → Open and confirm. It is unsigned, so a normal double-click can be blocked by Gatekeeper.

Build from this repo (Node + Rust). Compose runs in-process; the window is a webview, not a hidden Next server.

cd web && npm install && cd ..
npm --prefix web run desktop:build

That writes a universal .app (Apple Silicon + Intel) and a .dmg:

• target/universal-apple-darwin/release/bundle/macos/rytm-builder.app
• target/universal-apple-darwin/release/bundle/dmg/

macOS 10.15 Catalina is the claimed floor on Intel. Apple Silicon already needs Big Sur. Mojave and older are not a goal. A copy is usually placed on the Desktop after a local build. Library dumps stay in ~/Library/Application Support/rytm-builder/library. Download project / Download edits open Save As (Downloads by default) and also keep a copy under Application Support/rytm-builder/exports.

Dev window (same engine, not a website):

cd web && npm install && cd ..
npm --prefix web run desktop

Needs Rust 1.83 (or similar; not edition 2024). From this directory:

cargo build

The binary is target/debug/rytm-builder.

Keep personal .syx dumps out of git (they are gitignored). Point the CLI at a local dumps folder.

Drop dumps into the app library, place pattern+kit pairs on an A–H × 1–16 dest grid (empty cells stay empty), switch to KIT for dest kit slots 00–127, or PAT to overwrite dest pattern slots while keeping dest kit numbers. Drag dest cells/rows to rearrange (vacate or swap). Grey matches dest base; red is the differential. Download project writes a whole-project .syx (empty/disposable RAM). Download edits writes settings + changed kits/patterns only (dest-base already in RAM). Kit-tab edits omit pattern objects; pattern-tab edits omit unchanged kits. This tool never talks USB. Restore model: receive the file in a sysex editor.

cargo run -- catalog /path/to/Untitled.syx

Prints nonempty patterns (A01–H16), linked kit name/index, trig counts, and kits that have names or sample slots.

Use an empty whole-project dump as --template (a newly created Rytm project, saved and dumped — not a file this tool “clears”). Copy one or more PATH:PATTERN or PATH:PATTERN:DEST pairs. With no dest, slots fill from the first empty pattern (legacy). With dest (e.g. C04), that cell is written and others stay empty. --vacate A03 empties a dest pattern (needed when rearranging dest-base cells). --copy-kit PATH:KIT:DEST overwrites dest kit DEST (A01–H16 = kit 0–127) and remaps sample fingerprints; patterns are not written. Occupied dest kits are overwritten so patterns already using that kit pick up the new analog. --vacate-kit empties a dest kit object.

cargo run -- compose \
  --template /path/to/Untitled-4.syx \
  --out /path/to/Fresh.syx \
  --copy /path/to/Untitled-1.syx:A03:C04 \
  --copy /path/to/Untitled.syx:A01:C05 \
  --report /path/to/Fresh.txt

Kit-only (no pattern write):

cargo run -- compose \
  --template /path/to/Untitled.syx \
  --edits-out /path/to/KitSwap__edits.syx \
  --copy-kit /path/to/Untitled-1.syx:A03:A01

Pattern-only (keeps dest kit number):

cargo run -- compose \
  --template /path/to/Untitled.syx \
  --edits-out /path/to/PatSwap__edits.syx \
  --copy-pattern /path/to/Untitled-1.syx:A03:A01

Rules the tool will not bend:

• Never overwrites --out or --report if the path already exists.
• Remaps pattern kit_number, kit sample_nr, and SMP_NR parameter locks.
• Reuses a destination sample slot when the 16-byte fingerprint already exists; otherwise allocates the next empty slot (1–127).
• Writes settings, then globals, then kits/sounds/patterns/songs. Kits-first is how samples show as OFF on the box.
• After writing, checks that template and source dumps are still byte-identical.

This app never talks to the device. Receive the downloaded .syx in Transfer / C6 / similar.

Whole project (--out / Download project):

1. Samples for those fingerprints must already be on +Drive.
2. Open an empty or disposable project in RAM (do not send onto a project you care about).
3. Receive the .syx as a whole project.
4. Check pattern slots, kit names, analog sound, and that samples are bound (not SMPL OFF).
5. Save the project on the device if it sounds right.

Edits (--edits-out / Download edits):

1. The project already in RAM must be the dest-base dump (grey cells).
2. Receive the smaller .syx (settings, then kits, then patterns). Vacated slots come through as empty patterns.
3. Same sample / analog checks on the red cells only. Grey neighbours should be untouched.

No live USB, no firmware SysEx, no Transfer .arpj, no sample upload, no song editing, no in-place project surgery, no sample names, no Windows .exe yet.

From empty template Untitled-4.syx:

Output example: Fresh__from_Untitled4_BLKWAX_MD1.syx (settings-first, 405 messages, 17 allocated sample slots). Restore that file on the box before composing bigger packs.