TwelveTake REAPER MCP

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: 1.6.0

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

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 3.8+ (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.

Copy reaper_mcp_bridge.lua to your REAPER Scripts folder:
- Windows: %APPDATA%\REAPER\Scripts\
- macOS: ~/Library/Application Support/REAPER/Scripts/
- Linux: ~/.config/REAPER/Scripts/
In REAPER: Actions → Show action list → Load ReaScript
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: %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)

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 (dB)
`get_track_peak_hold(index, channel)`	Get held peak since last reset (dB)
`clear_all_peak_indicators()`	Reset peak hold on all tracks
`get_track_master_send(index)`	Get master/parent send state
`set_track_master_send(index, enabled)`	Enable/disable master send
`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 (16 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, position?)`	Add FX plugin (optionally at position)
`track_fx_move(index, fx_index, new_position)`	Reorder FX in the chain
`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

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.

Tool	Description
`find_eq(track, instantiate?)`	Find ReaEQ on a track (optionally add it)
`get_eq_bands(track, fx)`	Read all ReaEQ bands with human-readable values
`set_eq_band(track, fx, bandtype, bandidx, paramtype, value, is_normalized?)`	Set a band parameter (Hz, dB, or Q)
`get_eq_band_enabled(track, fx, bandtype, bandidx?)`	Check whether a band is enabled
`set_eq_band_enabled(track, fx, bandtype, bandidx?, enabled?)`	Enable/disable a band

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).

Tool	Description
`take_fx_get_count(track, item, take)`	Count FX on a take
`take_fx_get_list(track, item, take)`	List all take FX with details
`take_fx_add_by_name(track, item, take, name)`	Add FX plugin to a take
`take_fx_delete(track, item, take, fx)`	Remove FX from a take
`take_fx_get_name(track, item, take, fx)`	Get take FX name
`take_fx_get_enabled(track, item, take, fx)`	Check if enabled
`take_fx_set_enabled(track, item, take, fx, enabled)`	Enable/bypass take FX
`take_fx_get_num_params(track, item, take, fx)`	Count parameters
`take_fx_get_param_name(track, item, take, fx, param)`	Get parameter name
`take_fx_get_param(track, item, take, fx, param)`	Get parameter value
`take_fx_set_param(track, item, take, fx, param, value)`	Set parameter value

Take Management & Comping (7 tools)

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

Tool	Description
`get_takes(track, item)`	List all takes (name + active flag)
`get_active_take(track, item)`	Get the active take index
`set_active_take(track, item, take)`	Switch which take plays
`explode_takes(track, item)`	Explode takes to overlapping items (in place)
`crop_to_active_take(track, item)`	Keep only the active take
`delete_take(track, item, take)`	Delete a specific take
`select_comp_lane(track, lane)`	Play one fixed lane exclusively (lane comping)

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_beat, length_beats, chan)`	Add single note (beats)
`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

MIDI Utilities (13 tools)

Editing tools for notes that already exist. Every one takes the same optional filter — a pitch range, an onset window in beats from the item start, and a channel — so you can target a phrase without selecting anything by hand. Timing is in beats, pitch in semitones. Each is one undo step.

Tool	Description
`transpose_midi_notes(track, item, semitones, ...)`	Shift pitch; notes pushed outside 0-127 are left alone, never wrapped
`snap_midi_notes_to_scale(track, item, root, mode, ...)`	Snap off-key notes onto a scale (named or a custom interval list)
`quantize_midi_notes(track, item, grid, strength, swing, ...)`	Snap onsets to the project grid, with strength and swing
`nudge_midi_notes(track, item, amount_beats, ...)`	Shift notes in time; lengths preserved
`stretch_midi_notes(track, item, factor, pivot_beat, ...)`	Scale timing about a pivot (half-time / double-time)
`legato_midi_notes(track, item, mode, voice, ...)`	Close the gaps in a line, or set every note to one length
`humanize_midi_notes(track, item, timing, velocity, seed, ...)`	Seeded, reproducible timing + velocity jitter
`strum_midi_notes(track, item, spread_beats, direction, ...)`	Roll a chord out into a strum
`ramp_midi_note_velocities(track, item, start_vel, end_vel, ...)`	Linear velocity ramp across a phrase (crescendo)
`scale_midi_note_velocities(track, item, mode, ratio, ...)`	Multiply / set / compress velocities
`set_midi_note(track, item, note, ...)`	Edit one note's pitch, velocity, timing, channel
`get_selected_midi_notes(track, item)`	Read the notes selected in REAPER's editor
`remove_overlapping_midi_notes(track, item, mode, ...)`	Trim or delete overlapping same-pitch notes

remove_overlapping_midi_notes is the only one here that can remove notes; the rest only move what is already there. It is flagged destructive so a client can prompt first.

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

FX Parameter Automation (5 tools)

Tool	Description
`get_fx_envelope(track, fx, param)`	Get/create envelope for any FX parameter
`add_fx_envelope_point(track, fx, param, time, value, shape)`	Add automation point to FX parameter
`get_fx_envelope_points(track, fx, param)`	Get all points from FX envelope
`delete_fx_envelope_point(track, fx, param, point)`	Delete point from FX envelope
`clear_fx_envelope(track, fx, param)`	Clear all points from FX envelope

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"

Ensure REAPER is running
Ensure the bridge script is running (check REAPER's console)
For file mode: verify the bridge directory exists
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

TwelveTake Studios LLC Website: twelvetake.com Contact: [email protected]

Reaper MCP

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