Reaper

TwelveTake REAPER MCP

A TwelveTake Studios project.

A comprehensive Model Context Protocol (MCP) server that enables AI assistants to control REAPER DAW for mixing, mastering, MIDI composition, and full music production workflows.

Version: 1.6.4

Why This Server

Workflow Automation, Not Just API Wrappers

Most MCP servers just wrap REAPER's API and call it a day. This one includes production workflow helpers that handle multi-step operations in a single call:

Zero Configuration

• File-based communication works immediately — no network setup, no ports to configure
• Stock REAPER Lua only — the bridge script has no dependencies, nothing extra to install in REAPER
• Copy the script, run it, connect your AI assistant

176 Tools Covering Real Production Needs

• Full FX control — add/remove plugins, get/set any parameter by index, manage presets, bypass
• FX parameter automation — automate any plugin knob (flanger depth, filter cutoff, etc.)
• Complete routing — sends, receives, sidechain routing to specific channel pairs
• Automation — create envelopes, add/edit points, set automation modes
• MIDI — create items, add notes individually or in batches, edit velocities
• MIDI editing — transpose, quantize with swing, humanize, snap to a scale, stretch, legato, strum, velocity ramps — each targetable by pitch range, beat window, or channel
• Audio items — import, split, duplicate, fade, position, mute
• Markers & regions — create, edit, navigate, render by region

Requirements

• REAPER (any recent version; full live suite green through REAPER 7.77)
• Python 3.10+ (for the MCP server)
• An MCP-compatible AI assistant

Installation

1. Install the Bridge Script in REAPER

The bridge script runs inside REAPER and handles communication with the MCP server.

The package can deploy it for you:

uvx twelvetake-reaper-mcp --install-bridge

That copies reaper_mcp_bridge.lua into REAPER's Scripts folder for your platform, backing up any existing copy first. It writes nothing else, and the server never touches your REAPER installation on its own. Pass a path if REAPER is portable or installed somewhere unusual: --install-bridge "/path/to/REAPER/Scripts".

To do it by hand instead:

1. Copy reaper_mcp_bridge.lua to your REAPER Scripts folder:
   • Windows: %APPDATA%\REAPER\Scripts\
   • macOS: ~/Library/Application Support/REAPER/Scripts/
   • Linux: ~/.config/REAPER/Scripts/
2. In REAPER: Actions → Show action list → Load ReaScript
3. Select reaper_mcp_bridge.lua and click Run

You should see "REAPER MCP Bridge (File-based, Full API) started" in REAPER's console.

2. Install and Configure the MCP Server

The server is published on PyPI as twelvetake-reaper-mcp. The simplest path is to let your MCP client launch it with uvx (or pipx) — nothing to install by hand.

Add it to your MCP client's configuration (e.g. .mcp.json, or your client's MCP settings):

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

VS Code uses a top-level servers key with "type": "stdio" instead of mcpServers.

To confirm the server starts on its own:

uvx twelvetake-reaper-mcp
# or: pipx run twelvetake-reaper-mcp

It waits quietly for a client to connect — press Ctrl+C to stop.

3. Verify

With REAPER open and the bridge running, ask your assistant "how many tracks are in my project?" — a number back means the server, bridge, and REAPER are all talking.

Run from source (for development)

To work on the server itself, run it from a clone instead of from PyPI. Install the dependencies:

pip install -r requirements.txt   # or: pip install mcp httpx

Point your MCP client at the local script:

{
  "mcpServers": {
    "reaper": {
      "command": "python",
      "args": ["path/to/reaper_mcp_server.py"]
    }
  }
}

Then check the connection with:

python test_connection.py

Nix flake (optional)

If you use Nix, the repo ships a flake-based dev shell that provides Python 3.12 and creates/activates a virtualenv for you:

# Enter the dev shell manually
nix develop

# Or, with direnv, auto-activate on cd:
direnv allow

Then install the dependencies as usual:

pip install -r requirements.txt

This pins the Python version and keeps dependencies isolated from your system.

Note: the x86_64-linux dev shell is tested and working. The macOS (Darwin) shells are provided but have not been tested — confirmation from a macOS user is welcome.

Communication Modes

The file-based bridge is the supported path — it is reliable and needs no extra setup. HTTP mode is deprecated (see below).

File-Based (Default, Recommended)

Uses JSON files for communication. More reliable, no network configuration needed. This is the only actively maintained path; all tools are guaranteed to work here.

MCP Server                    REAPER Bridge
    │                              │
    ├── writes request_N.json ────►│
    │                              ├── processes request
    │◄── reads response_N.json ────┤

Bridge directory: REAPER's own Scripts/mcp_bridge_data, resolved per platform:

Override with REAPER_BRIDGE_DIR for portable installs. The server prints the directory it resolved to stderr on startup, and includes it in any timeout error.

HTTP Mode (Deprecated)

Deprecated as of v1.2.1. The HTTP bridges (reaper_web_server.lua / reaper_web_server.py) are kept for existing users but are no longer maintained and will not receive new tools. They may be removed in a future major release (v2.0). Use the file bridge instead.

Uses HTTP requests on localhost. Requires additional setup:

• Lua HTTP bridge: Requires LuaSocket (install via ReaPack → "sockmonkey")
• Python HTTP bridge: Requires Python enabled in REAPER preferences

# Set environment variable to use HTTP mode
REAPER_COMM_MODE=http python reaper_mcp_server.py

Default port: 9000

Quick Start Examples

Basic Track Operations

"How many tracks are in my project?"
"Create a new track called 'Vocals'"
"Set track 0 volume to -6dB"
"Mute track 2"
"Solo the drums track"

Mixing

"Add ReaComp to the bass track"
"Set up sidechain compression from the kick to the bass"
"Create a drum bus and route tracks 0-3 to it"
"Add a mastering chain to the master track"

FX and Parameters

"What plugins are on track 0?"
"Get the parameters for the compressor on track 1"
"Set the threshold to -20dB"
"Bypass the EQ on the vocal track"

MIDI Composition

"Create a 4-bar MIDI item on track 0"
"Add a C major chord at the start"
"Get all the notes in the MIDI item"
"Set the velocity of note 0 to 100"

Transport and Navigation

"Play the project"
"Stop playback"
"Set the cursor to 30 seconds"
"Add a marker called 'Chorus' at the current position"

Project Management

"What's the project tempo?"
"Set the tempo to 120 BPM"
"Save the project"
"Render to D:/Output/mix.wav"

Tool Reference

Track Operations (23 tools)

FX Operations (16 tools)

ReaEQ Operations (5 tools)

Dedicated ReaEQ band control using REAPER's EQ-specific API, which handles ReaEQ's non-linear parameter curves (dB gain, log frequency, log Q) correctly.

Take FX Operations (11 tools)

Per-take (per-item) FX, mirroring the track FX tools. Every take is addressed by `(track_i

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