MCP MIDI Server

A FastMCP Server which allows an LLM to send MIDI sequences into any software that supports MIDI input.

Features

Creates a virtual MIDI output port
Sends MIDI Note On/Off messages
Sends Control Change (CC) messages
Sequences MIDI events with precise timing
Can be used as a MIDI input device in any application that supports MIDI

Related MCP server: Awesome MCP FastAPI

Requirements

Python 3.7+
rtmidi
fastmcp
python-dotenv
asyncio

Installation

Clone the repository:
git clone <repository-url> cd mcp-server-midi
Create a virtual env, activate it and install dependencies:
python -m venv .venv source .venv/bin/activate pip install -r requirements.txt
Create a .env file with your configuration:
PORT=8123

Usage

Run the server:

python mcp_midi_server.py

The server creates a virtual MIDI port named "MCP MIDI Out" that can be used as a MIDI input device in other applications. This means you can:

Connect digital audio workstations (DAWs) like Ableton Live, Logic Pro, or FL Studio to receive MIDI from this server
Use the server to control hardware synthesizers through your computer's MIDI interface
Connect to any other software that accepts MIDI input (virtual instruments, lighting controllers, etc.)

Simply select "MCP MIDI Out" as a MIDI input device in your preferred MIDI-compatible application.

MCP Config

The server uses Server-Sent Events (SSE), this is how to config it in Cursor:

{ "mcpServers": { "midi": { "url": "http://localhost:8123/sse" } } }

API Methods

Send Note On

Sends a MIDI Note On message.

Parameters:

note: MIDI note number (0-127)
velocity: Note velocity (0-127, default 127)
channel: MIDI channel (0-15, default 0)

Send Note Off

Sends a MIDI Note Off message.

Parameters:

note: MIDI note number (0-127)
velocity: Note off velocity (0-127, default 64)
channel: MIDI channel (0-15, default 0)

Send Control Change

Sends a MIDI Control Change (CC) message.

Parameters:

controller: CC controller number (0-127)
value: CC value (0-127)
channel: MIDI channel (0-15, default 0)

Send MIDI Sequence

Sends a sequence of MIDI Note On/Off messages with specified durations.

Parameters:

events: A list of event dictionaries. Each dictionary must contain:
- note: MIDI note number (0-127)
- velocity: Note velocity (0-127, default 127)
- channel: MIDI channel (0-15, default 0)
- duration: Time in seconds to hold the note before sending Note Off
- start_time: Time in seconds when to start the note, relative to sequence start (default 0)

Example

Using the API to play a C major chord:

events = [ {"note": 60, "velocity": 100, "duration": 1.0, "start_time": 0.0}, # C4 {"note": 64, "velocity": 100, "duration": 1.0, "start_time": 0.0}, # E4 {"note": 67, "velocity": 100, "duration": 1.0, "start_time": 0.0}, # G4 ] # Send to the MCP MIDI Server API