Reaper MCP

What TwelveTake-Studios/reaper-mcp does

TwelveTake-Studios/reaper-mcp lets an MCP-compatible AI assistant operate REAPER projects. Its coverage spans track inspection and editing, FX management, routing, automation, MIDI composition and editing, audio-item operations, markers and regions, and audio measurement.

Track tools can report project and master-track details, create or remove tracks, rename tracks, adjust volume and pan, and change mute or solo state. FX tools work with both track and take chains: an assistant can list plugins, add them by the exact name shown in REAPER, move or remove them, bypass or enable them, and read or change plugin parameters.

Higher-level workflow operations combine several REAPER actions. Examples include creating a bus, setting up sidechain compression, adding a mastering chain, configuring parallel compression, and retrieving a project summary containing tracks, FX, markers, regions, tempo, and time signature.

How it works

The Python MCP process communicates with a Lua bridge running inside REAPER. The bridge is loaded as a ReaScript and remains active in the background while REAPER is open. The MCP server is normally launched over standard input and output by an MCP client, commonly through uvx.

The measurement features also use a TwelveTake analyzer JSFX installed in REAPER. Measurement coverage includes loudness, loudness range, true peak, octave-band spectrum, and stereo correlation for the master, a track, or an item. Changes made through the server are recorded as named, individual steps in REAPER's undo history, allowing a tool call to be reversed with REAPER's normal undo command.

Setup and configuration

REAPER, Python 3.10 or newer, and an MCP-compatible AI assistant are required. The project supports recent REAPER versions, with the documented live test suite covering REAPER 7.79.

Install the bridge and analyzer with the package command:

uvx twelvetake-reaper-mcp --install-bridge

The command places the Lua script in REAPER's Scripts folder and installs the analyzer under Effects/TwelveTake. A custom Scripts path can be supplied for portable or nonstandard REAPER installations. The bridge must then be loaded and run from REAPER's Actions list. ReaPack and manual installation are also supported.

To start the bridge whenever REAPER launches, use --autostart; --remove-autostart removes that startup entry. The MCP server itself can be added to a client using a standard stdio configuration:

{
  "mcpServers": {
    "reaper": {
      "command": "uvx",
      "args": ["twelvetake-reaper-mcp"]
    }
  }
}

VS Code uses a top-level servers configuration with an explicit stdio type. The server can also be run with pipx run twelvetake-reaper-mcp.

Tools and capabilities

• Inspect project, master-track, track, take, FX, parameter, marker, region, tempo, and time-signature state.
• Create, rename, modify, route, and remove tracks, including buses and parallel-compression setups.
• Add, reorder, bypass, delete, and parameterize track or take FX.
• Create and edit MIDI items and notes, including quantization, transposition, humanization, scale snapping, stretching, legato, strumming, and velocity changes.
• Import, split, duplicate, position, mute, and fade audio items.
• Create automation envelopes and points, set automation modes, manage markers and regions, and render by region.
• Measure loudness, true peak, loudness range, spectrum, and stereo correlation.

Limitations and notes

FX must be referenced using the exact plugin name shown in REAPER's FX browser. Track indexes are zero-based, and the master track cannot be deleted. Normal track FX-chain tools do not cover input or record FX, or master monitoring FX. The analyzer installation is needed for measurement tools but not for the other capabilities.