fl-bridge-mcp

An unofficial MCP (Model Context Protocol) bridge for FL Studio. Not affiliated with or endorsed by Image-Line. FL Studio is a trademark of Image-Line Software.

Talk to FL Studio from Claude (or any MCP client): transport, tempo, pattern jumps, step-sequencer programming, mixer moves, live notes, chord progressions — and, unlike a fire-and-forget MIDI blaster, it is built to read FL's state back over a return port.

Status (v0.2.0): the command path — tempo, transport, notes — is verified live by ear on FL Studio 2026 / macOS. The return port connects (FL handshakes on it), but status reports have not yet been confirmed end to end, so treat get_status and list_channels as beta. Reports welcome.

How it works

MCP client ── stdio ──> server.py ── virtual MIDI "M5 FL Bridge" ──> FL Studio
                            ^                                          │
                            └── virtual MIDI "M5 FL Bridge Return" <───┘

• server.py opens two virtual CoreMIDI ports and exposes 18 MCP tools.

• device_M5FLBridge.py (an FL MIDI controller script) decodes commands and drives FL's scripting API; it reports state back via SysEx.

• Commands ride in SysEx under manufacturer id 0x7D (the dev/educational id) so they can never collide with note traffic. Notes ride as plain note_on/note_off that the script deliberately leaves unhandled — FL routes them to the selected channel exactly like a hardware keyboard, which is what makes them audible and recordable.

Related MCP server: FL Studio MCP

Install

1. python3 -m venv venv && ./venv/bin/pip install -r requirements.txt (pin matters: mcp<2 — the 2.x SDK renamed FastMCP)

2. Copy the M5 FL Bridge folder into FL's controller-script directory:

   • macOS: ~/Documents/Image-Line/FL Studio/Settings/Hardware/

   • Windows: %USERPROFILE%\Documents\Image-Line\FL Studio\Settings\Hardware\

3. Register the server with your MCP client, e.g. for Claude Code (~/.claude.json → mcpServers):

   "flstudio": {"type": "stdio",
                "command": "/path/to/venv/bin/python",
                "args": ["/path/to/server.py"]}

Wire it up in FL (once)

With the MCP server running (the ports only exist while it lives):

1. Options → MIDI settings

2. Input list → M5 FL Bridge → Enable, controller type M5 FL Bridge (user)

3. (for state read-back) Output list → M5 FL Bridge Return → Enable, and give it the same port number as the input — that links it to the controller so the script's replies have somewhere to go

4. View → Script output should greet you: M5 FL Bridge v0.2 online

Skipping step 3 costs you get_status and list_channels; everything else still works.

Tools

Wire protocol

F0 7D <cmd> <payload> F7 — multi-byte values are two 7-bit bytes, MSB first.

Limits (honest ones)

• The FL MIDI-scripting API is a controller surface, not a project editor: no playlist arrangement, no plugin-parameter surgery, no piano-roll writing. Recording play_notes while transport records is the way to get notes into a pattern.

• Notes land on the selected channel; list_channels then channel_select is the aiming sequence.

• Built and tested on macOS (CoreMIDI). Windows needs a virtual-MIDI driver (loopMIDI) instead of virtual=True ports — untested.

MIT licensed (see LICENSE); scratches my itch, PRs welcome, no SLA.