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.

Built by a working producer with 7+ albums released. These aren't theoretical tools—they're battle-tested in real sessions.

Version: 1.5.0

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

163 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
• Audio items — import, split, duplicate, fade, position, mute
• Markers & regions — create, edit, navigate, render by region

Requirements

• REAPER (any recent version)
• Python 3.8+ (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.

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 started" in REAPER's console.

2. Install the MCP Server

pip install -r requirements.txt

Or install dependencies directly:

pip install mcp httpx

Alternative: 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.

3. Configure Your AI Assistant

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

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

4. Verify Connection

python test_connection.py

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: %APPDATA%\REAPER\Scripts\mcp_bridge_data

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_index, item_index, take_index).

Take Management & Comping (7 tools)

Multi-take workflows: list/switch/delete takes, explode/crop, REAPER 7 fixed-lane comping.

Routing (9 tools)

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