djay Pro MCP

An MCP server that lets Claude (or any MCP client) drive djay Pro for Mac (Algoriddim): decks, mixer, tempo and sync, loops, hot cues, FX, Neural Mix, sampler, looper, Automix, recording, layouts, menus and the music library, plus automated transitions between decks.

It was built by reverse-engineering djay Pro 5.6.10 with REA (Reverse Engineer Anything). See docs/REVERSE_ENGINEERING.md for what was found and how.

How it works

djay has no scripting API, so the server uses three channels djay already supports:

The ports are named Global djay MCP, One djay MCP, Two djay MCP, Three djay MCP and Four djay MCP. The global port carries mixer, app, library, sampler, looper and microphone features. Each deck port carries one deck's features. djay sees them as five connected controllers.

Related MCP server: Logic Pro MCP Server

Requirements

• macOS with djay Pro installed at /Applications/djay Pro.app (set DJAY_APP_PATH to override)

• Node.js 22.13 or newer (uses the built-in node:sqlite)

• Xcode command line tools (swiftc) to build the three small Swift helpers

• Accessibility permission for the app that launches the server (Claude, Terminal...): System Settings > Privacy & Security > Accessibility

Install

git clone https://github.com/ckryptickunal/djay-pro-mcp.git

cd djay-pro-mcp && npm install && npm run build

npm run setup

npm run build compiles the TypeScript server and the Swift helpers. npm run setup writes the five mapping files. djay reads mappings only when it launches, so restart djay Pro once afterwards. The djay_setup tool with restart_djay: true does both for you.

Register with Claude Code, from inside the project folder:

claude mcp add --scope user djay-pro -- "$(which node)" --disable-warning=ExperimentalWarning "$(pwd)/dist/index.js"

Other MCP clients: run node --disable-warning=ExperimentalWarning /path/to/djay-pro-mcp/dist/index.js as a stdio server.

Check everything with:

npm run doctor

Tools

Start with djay_status. It reports whether djay is running, whether the mappings are installed and current, and whether djay is sending state back.

Continuous values are 0..1. For EQ, filter, gain, pan and tempo, 0.5 is neutral; for the crossfader, 0 is left and 1 is right.

Example requests

• "Load Digital Love by Daft Punk on deck 1 and One More Time on deck 2, match their BPM, and do a 32-beat bass-swap transition."

• "Find tracks between 120 and 126 BPM that mix harmonically with 8A."

• "Set a 4-beat loop on deck 1, then fade the filter to high-pass over 8 seconds."

• "What did I play in my last DJ session?"

What was tested live (djay 5.6.10, macOS 27.0.1)

Tested end to end through the MCP protocol, with master volume at 0:

• Setup, restarting djay, all five ports connecting (at djay launch and hot-plugged while djay runs), about 1,900 live state values

• Library database search and filters; history, queue and stats; djay's search box and the results panel

• Loading Spotify tracks onto decks 1 and 2, refusing loads when no result matches

• Play/pause (idempotent), tempo % (exact to 0.1%), BPM matching, sync, 4-beat loop on/off, setting a hot cue, FX slot on/wet-dry/off, eject

• An 8-beat bass_swap transition from deck 1 to deck 2

• Automix on, skip, off

• Mix recording start/stop (with no streaming tracks loaded)

• Menu clicks, accessibility search, screenshots

Built but not yet exercised live: sampler, looper, view modes, djay_sequence, the other transition styles, tempo nudge, crossfader curve menu, loading from a local file path, opening playlists from the sidebar.

Known limits

• djay must be restarted once after mappings are installed or regenerated (for example after a djay update; djay_status tells you).

• Auto-play on load: djay may start a deck when a track loads. djay_load pauses it again unless you pass play: true.

• Recording does not start while streaming-service tracks are loaded on a deck (observed with Spotify); it works with local files.

• Neural Mix stem mute did not engage on the Spotify tracks used in testing. The cause (track source or subscription) was not confirmed. The tool reports a warning when djay does not change state.

• One session at a time: each running copy of the server creates the five ports. Two Claude sessions using it at once would create duplicate controllers.

• Track text readouts (title, BPM, key, time) come from accessibility, so the main window must exist (it can be hidden behind other windows).

• No Ableton Link yet; tempo readouts come from djay's display (0.1 BPM resolution).

• The MCP produces real audio. Ask before playing loud material.

Uninstall

claude mcp remove djay-pro -s user

node dist/cli.js uninstall

The second command deletes only the five generated mapping files. Your own controller mappings in the same folder are never touched.

Project layout

bridge/        Swift helpers: MIDI ports, accessibility, window list
src/catalog.ts feature catalog built from djay's resource files
src/mapping.ts address allocation + mapping file generator
src/midi.ts    MIDI bridge client and feedback decoder
src/ax.ts      accessibility client and deck readout parser
src/library/   FastCoder decoder and library database reader
src/djay.ts    controller tying it together
src/mix.ts     automated transitions
src/tools/     MCP tool definitions
scripts/       build script and an end-to-end MCP test client
docs/          reverse-engineering notes

Disclaimer

This is an independent project. It is not affiliated with, endorsed by or supported by Algoriddim. djay and djay Pro are trademarks of Algoriddim GmbH. The server only talks to your own installed copy of djay through interfaces djay already offers (MIDI controller mappings, macOS accessibility and its local library file). It ships no djay code or resources, bypasses no licensing, and reads djay's resource files from your installation at runtime.

License

MIT. See LICENSE.