MIDI-GPT for REAPER
Open source (MIT). Available now as an early release (v0.1.1).
MIDI-GPT for REAPER brings MIDI-GPT, the Metacreation Lab's controllable multi-track MIDI transformer, directly into the REAPER digital audio workstation. Select a region of your project, choose which tracks and bars the model should touch, and generate: the plugin sends the MIDI already in your session to a MIDI-GPT inference server (local or remote) as context, then writes the result straight back into REAPER. One dashboard window covers the whole workflow, with no manual synth routing or file exporting.
What you can do
Fill in missing bars: select a region and the model generates notes that fit your existing arrangement.
Generate new tracks: create empty bars, name (or auto-detect) the track's instrument, and let the model compose from scratch.
Steer the output: per-track density, polyphony, note duration, pitch masking and remix controls, plus global sampling and validation settings.
Refine iteratively: regenerate any bar, track or region, and choose between multiple generated variations.
Stay in context: every request includes the surrounding MIDI, so results follow the key, groove and texture already in your project.
The dashboard
Server and model: connect to a local or remote MIDI-GPT server and pick a model.
Global options: Plan (context length, bars and tracks per step, seed), Sampling (temperature, top-p, top-k), Constraints (hard polyphony and density limits) and Quality (validation and retries).
Per-track controls: steer each track individually.
Automatic instrument setup: detects each track's instrument and configures playback with the Sforzando sampler and the Arachno GM SoundFont.
Getting started
MIDI-GPT for REAPER runs on macOS, Linux, and Windows 10/11 and requires REAPER 6 or later (64-bit) and Python 3.10 to 3.12. The installer sets up the ReaImGui extension for you. You can install it with a one-line command or by double-clicking the installer; see the documentation for details.
Tutorial Video
Releases
v0.1.1 (September 23, 2026)
Full release history on GitHub.
Links
MIDI-GPT library and its documentation
Related projects
Multi-track Music Generation (the MMM project overview)
Papers and Posters
Pasquier, P., Ens, J., Fradet, N., Triana, P., Rizzotti, D., Rolland, J.-B., & Safi, M. (2025). MIDI-GPT: A Controllable Generative Model for Computer-Assisted Multitrack Music Composition. arXiv:2501.17011
