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: 1.1.0

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:

Tool	What it does for you
setup_sidechain_compression()	Creates send, routes to channels 3-4, configures ReaComp's detector input — complete sidechain setup in one call
add_mastering_chain()	Adds ReaEQ → ReaComp → ReaEQ → ReaLimit to master track with proper signal flow
add_parallel_compression()	Creates a bus track, sets up the send, adds compressor — NY-style compression ready to blend
create_bus()	Creates a submix track and routes your specified tracks to it
get_project_summary()	Returns track count, all track names/volumes/pans/FX, markers, regions, tempo, time signature — everything your AI needs in one 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

130 Tools Covering Real Production Needs

• Full FX control — add/remove plugins, get/set any parameter by index, manage presets, bypass
• 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 (Claude, ChatGPT, etc.)

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

3. Configure Your AI Assistant

Add to your MCP configuration (e.g., ~/.claude.json or .mcp.json):

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

4. Verify Connection

python test_connection.py

Communication Modes

The MCP server supports two communication modes:

File-Based (Default)

Uses JSON files for communication. More reliable, no network configuration needed.

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

Bridge directory: %APPDATA%\REAPER\Scripts\mcp_bridge_data

HTTP Mode (Advanced)

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 (19 tools)

Tool	Description
get_track_count()	Get total number of tracks (excluding master)
get_track(index)	Get track info (name, volume, pan, mute, solo)
get_all_tracks()	Get info for all tracks
get_master_track()	Get master track info
insert_track(index, name)	Create a new track
delete_track(index)	Delete a track
set_track_name(index, name)	Rename a track
set_track_volume(index, db)	Set volume in dB
set_track_pan(index, pan)	Set pan (-1 to 1)
set_track_mute(index, mute)	Mute/unmute track
set_track_solo(index, solo)	Solo/unsolo track
set_track_phase(index, invert)	Invert phase
set_track_width(index, width)	Set stereo width (0-2)
set_track_color(index, r, g, b)	Set track color
get_track_peak(index, channel)	Get current peak level
set_track_as_folder(index, depth)	Set as folder parent/child
arm_track(index, arm)	Arm for recording
set_track_input(index, input)	Set record input
set_track_monitor(index, mode)	Set monitor mode

FX Operations (15 tools)

Tool	Description
track_fx_get_count(index)	Count FX on track
track_fx_get_list(index)	List all FX with details
track_fx_add_by_name(index, name)	Add FX plugin
track_fx_delete(index, fx_index)	Remove FX
track_fx_get_name(index, fx_index)	Get FX name
track_fx_get_enabled(index, fx_index)	Check if enabled
track_fx_set_enabled(index, fx_index, enabled)	Enable/bypass FX
track_fx_get_num_params(index, fx_index)	Count parameters
track_fx_get_param_name(index, fx_index, param)	Get parameter name
track_fx_get_param(index, fx_index, param)	Get parameter value
track_fx_set_param(index, fx_index, param, value)	Set parameter value
get_fx_presets(index, fx_index)	List available presets
get_fx_preset(index, fx_index)	Get current preset
set_fx_preset(index, fx_index, name)	Load preset
save_fx_preset(index, fx_index, name)	Save current settings as preset

Routing (9 tools)

Tool	Description
create_send(src, dest)	Create send between tracks
delete_send(index, send_index)	Remove a send
set_send_volume(index, send_index, db)	Set send level
get_track_num_sends(index)	Count sends from track
set_send_dest_channels(index, send_index, chan)	Route to specific channels
set_send_source_channels(index, send_index, chan)	Set source channels
setup_sidechain_send(src, dest, db)	Create sidechain send
configure_reacomp_sidechain(index, fx_index, use)	Configure ReaComp sidechain
setup_sidechain_compression(trigger, target, fx, db)	Complete sidechain setup

Transport (10 tools)

Tool	Description
play()	Start playback
stop()	Stop playback
pause()	Pause playback
record()	Start recording
get_play_state()	Get current state (playing/paused/recording)
get_cursor_position()	Get edit cursor position (seconds)
set_cursor_position(seconds)	Move edit cursor
get_play_position()	Get playback position (seconds)
toggle_repeat()	Toggle loop mode
get_repeat_state()	Check if looping

Project (15 tools)

Tool	Description
get_project_summary()	Get comprehensive project state in one call
save_project()	Save current project
create_project(name)	Create new project
open_project(path)	Open project file
get_project_path()	Get project directory
get_project_name()	Get project filename
get_project_length()	Get project length (seconds)
get_tempo()	Get project tempo (BPM)
set_tempo(bpm)	Set project tempo
get_time_signature()	Get time signature
set_time_signature(num, denom)	Set time signature
render_project(path, start, end, tail)	Render to audio file
render_region(index, path)	Render specific region
zoom_to_selection()	Zoom to time selection
zoom_to_project()	Zoom to show entire project

MIDI Operations (8 tools)

Tool	Description
create_midi_item(track, pos, length)	Create empty MIDI item
get_midi_item(track, item)	Get MIDI item info
add_midi_note(track, item, pitch, vel, start, end, chan)	Add single note
add_midi_notes_batch(track, item, notes)	Add multiple notes
get_midi_notes(track, item)	Get all notes
delete_midi_note(track, item, note)	Delete a note
clear_midi_item(track, item)	Delete all notes
set_midi_note_velocity(track, item, note, vel)	Change note velocity

Audio Items (17 tools)

Tool	Description
insert_audio_file(track, path, pos)	Import audio file
get_track_items(track)	List all items on track
get_item_info(track, item)	Get item details
set_item_position(track, item, pos)	Move item
set_item_length(track, item, length)	Change item length
delete_item(track, item)	Delete item
duplicate_item(track, item)	Duplicate item
split_item(track, item, pos)	Split item at position
set_item_mute(track, item, mute)	Mute/unmute item
set_item_volume(track, item, db)	Set item volume
set_item_fade_in(track, item, length)	Set fade-in
set_item_fade_out(track, item, length)	Set fade-out
select_all_items()	Select all items
unselect_all_items()	Deselect all items
get_selected_items()	Get selected items
copy_selected_items()	Copy to clipboard
paste_items()	Paste from clipboard

Markers & Regions (8 tools)

Tool	Description
add_marker(pos, name, color)	Add marker
add_region(start, end, name, color)	Add region
get_markers()	Get all markers
get_regions()	Get all regions
delete_marker(index)	Delete marker
delete_region(index)	Delete region
go_to_marker(index)	Jump to marker
go_to_region(index)	Jump to region start

Automation (8 tools)

Tool	Description
get_track_envelope(track, name)	Get envelope by name
get_envelope_point_count(track, name)	Count envelope points
add_envelope_point(track, name, time, value, shape)	Add automation point
get_envelope_points(track, name)	Get all points
delete_envelope_point(track, name, index)	Delete point
clear_envelope(track, name)	Clear all points
set_track_automation_mode(track, mode)	Set automation mode
arm_track_envelope(track, name, arm)	Arm envelope for recording

Selection & Editing (11 tools)

Tool	Description
undo()	Undo last action
redo()	Redo last undone action
get_undo_state()	Get undo/redo state
select_track(index, exclusive)	Select a track
select_all_tracks()	Select all tracks
unselect_all_tracks()	Deselect all tracks
get_selected_tracks()	Get selected track indices
set_time_selection(start, end)	Set time selection
get_time_selection()	Get time selection
clear_time_selection()	Clear time selection
delete_selected_items()	Delete selected items

Mixing Helpers (6 tools)

Tool	Description
add_mastering_chain()	Add EQ→Comp→EQ→Limiter to master
add_parallel_compression(track, db)	Set up NY compression
create_bus(name, tracks)	Create submix bus
add_eq(track)	Add ReaEQ
add_compressor(track)	Add ReaComp
add_limiter(track)	Add ReaLimit

Advanced (4 tools)

Tool	Description
run_action(action_id)	Run REAPER action by ID
run_action_by_name(name)	Run action by name
get_track_fx_chunk(track, fx)	Get raw FX state data
cut_selected_items()	Cut items to clipboard

Track Indexing

• Regular tracks: 0-based index (first track = 0)
• Master track: Use index -1

"Set the master track volume to -3dB"  → track_index = -1
"Mute track 1"                          → track_index = 1 (second track)

Common Plugin Names

Use these names with track_fx_add_by_name():

Plugin	Name
EQ	ReaEQ
Compressor	ReaComp
Limiter	ReaLimit
Gate	ReaGate
Delay	ReaDelay
Reverb	ReaVerbate or ReaVerb

Third-party plugins use their full name as shown in REAPER's FX browser.

Troubleshooting

"Cannot connect to REAPER"

1. Ensure REAPER is running
2. Ensure the bridge script is running (check REAPER's console)
3. For file mode: verify the bridge directory exists
4. For HTTP mode: check port 9000 isn't blocked

"Track not found"

• Track indices are 0-based
• Use -1 for master track
• Check track count with get_track_count()

Bridge script won't load

• Lua: Ensure LuaSocket is installed (ReaPack → "sockmonkey")
• Python: Enable Python in REAPER preferences

Slow response

• File-based mode has ~50ms latency per call
• Batch operations when possible (e.g., add_midi_notes_batch)

Environment Variables

Variable	Default	Description
REAPER_COMM_MODE	file	Communication mode (file or http)
REAPER_BRIDGE_DIR	%APPDATA%\REAPER\Scripts\mcp_bridge_data	File bridge directory
REAPER_HOST	localhost	HTTP bridge host
REAPER_PORT	9000	HTTP bridge port

License

MIT License - see LICENSE

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TwelveTake Studios LLC Website: twelvetake.com Contact: contact@twelvetake.com