Songs as words / tools for people & agents
A song you can read.
Compose in the grid, or describe the same music in plain text.
Write. Check. Apply.
A Tracklet script describes a whole song: its key and tempo, tracks and voices, patterns, and arrangement. A line of notes is a row in the grid; a dot leaves a track empty on that step.
The SCRIPT panel checks your text as you type and reports mistakes with line numbers. Applying a valid script is one undoable action. An invalid script leaves the song alone.
This example is taken directly from the project’s documentation. Four tracks play a 16-step phrase over A minor, F, C and G. Change the tempo or a voice and hear the same idea differently.
↓ Download example
# TRACKLET SCRIPT - paste this box and press APPLY.
# A line with no command word is a GRID ROW: one step per line,
# one column per track. "." leaves that column empty for that step.
new
song "FIRST SCRIPT"
key A minor
tempo 128
tracks 4
track 1 "LEAD" voice lead
track 2 "BASS" voice bass level 65
track 3 "PAD" voice pad hold 4 level 45
track 4 "HAT" voice hat
pattern 1 "VERSE"
A-4 A-2 E-4 C-6
C-5 . . .
E-5 . . C-6
C-5 . . .
F-4 F-2 C-5 C-6
A-4 . . .
C-5 . . C-6
A-4 . . .
C-5 C-3 G-4 C-6
E-5 . . .
G-5 . . C-6
E-5 . . .
G-4 G-2 D-5 C-6
B-4 . . .
D-5 . . C-6
B-4 . . .
The same musical model, outside the window.
Tracklet exposes its model through a TypeScript API, a CLI, JSON-RPC over HTTP, and MCP. A connected client can ask what the current build supports, validate scripts, make and inspect songs, edit individual notes or mixer settings, and export MIDI.
The local agent server has its own model state. It does not change the open application’s memory: the handoff is a saved song you open, or a script you paste into the app.
HTTP connection
From the Tracklet project folder, start npm run api:server. Its default MCP endpoint is:
http://127.0.0.1:4590/mcp
Stdio connection
An MCP client can launch npm run mcp in the project folder and communicate over stdin and stdout. The client discovers the available tools from the running build.
A reference that speaks the app’s language.
The project’s SKILL.md gives an agent the command vocabulary, supported voices, limits, validation rules and composition examples. It is the guide for writing music Tracklet can actually understand. Pair it with the build’s language tools before generating a song.
The downloadable reference is a snapshot supplied with this showcase. Consult the repository for the latest build.