PostFader — Claude Code MCP server: what it does, how to install
Connects your MCP assistant directly to an active FL Studio session to inspect routing, balance audio, write notes, and adjust mixer values.
claude mcp add postfader-fl-studio-mcp -e FL_BRIDGE_ENABLE_MIDI=<FL_BRIDGE_ENABLE_MIDI> -e FL_BRIDGE_MIDI_PORT=<FL_BRIDGE_MIDI_PORT> -e FL_STUDIO_USER_DATA_DIR=<FL_STUDIO_USER_DATA_DIR> -- uvx postfader-fl-studio-mcpWhat PostFader does
PostFader establishes a local link between your assistant and an open FL Studio project using an internal Universal Bridge script and a virtual MIDI connection. The server supplies 85 tools. Through them, the assistant inspects channels, mixer routing, playlist arrangements, and exposed plugin knobs. Since FL Studio restricts live audio querying from scripts, loudness and tonal balance checks rely on bounced files.
Safety relies on strict state handling: operations start in read-only mode, moving to write actions only when you request an edit. After altering faders or panning, the bridge reads values back to confirm changes. Automatic saving is omitted. Running it demands FL Studio 2026 (release 26.1.3 or higher), Python from 3.10 to 3.14, and an active virtual MIDI port like loopMIDI or the macOS IAC driver.
What it helps with
- inspect unassigned mixer tracks and channel routings
- evaluate frequency balance and peaks on bounced audio files
- generate basslines and chord progressions into the Piano Roll
- adjust fader levels, panning, and aux send amounts
Example prompts for the agent
- Check the open project and identify any instruments lacking mixer routing.
- Lower the vocal reverb send by 3 dB and spread the backing tracks wider.
- Generate an 8-bar D Dorian bassline that fits my existing chord progression.
How to install PostFader
Platform CLI
claude mcp add postfader-fl-studio-mcp -e FL_BRIDGE_ENABLE_MIDI=<FL_BRIDGE_ENABLE_MIDI> -e FL_BRIDGE_MIDI_PORT=<FL_BRIDGE_MIDI_PORT> -e FL_STUDIO_USER_DATA_DIR=<FL_STUDIO_USER_DATA_DIR> -- uvx postfader-fl-studio-mcpReplace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from postfader-fl-studio-mcp <command>
Platform CLI
codex mcp add postfader --env FL_BRIDGE_ENABLE_MIDI=<FL_BRIDGE_ENABLE_MIDI> --env FL_BRIDGE_MIDI_PORT=<FL_BRIDGE_MIDI_PORT> --env FL_STUDIO_USER_DATA_DIR=<FL_STUDIO_USER_DATA_DIR> -- uvx postfader-fl-studio-mcpReplace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from postfader-fl-studio-mcp <command>
Config file
{
"mcpServers": {
"postfader": {
"command": "uvx",
"args": [
"postfader-fl-studio-mcp"
],
"env": {
"FL_BRIDGE_ENABLE_MIDI": "<FL_BRIDGE_ENABLE_MIDI>",
"FL_BRIDGE_MIDI_PORT": "<FL_BRIDGE_MIDI_PORT>",
"FL_STUDIO_USER_DATA_DIR": "<FL_STUDIO_USER_DATA_DIR>"
}
}
}
}Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from postfader-fl-studio-mcp <command>
Config file
{
"servers": {
"postfader": {
"type": "stdio",
"command": "uvx",
"args": [
"postfader-fl-studio-mcp"
],
"env": {
"FL_BRIDGE_ENABLE_MIDI": "<FL_BRIDGE_ENABLE_MIDI>",
"FL_BRIDGE_MIDI_PORT": "<FL_BRIDGE_MIDI_PORT>",
"FL_STUDIO_USER_DATA_DIR": "<FL_STUDIO_USER_DATA_DIR>"
}
}
}
}Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from postfader-fl-studio-mcp <command>
Platform CLI
gemini mcp add -e FL_BRIDGE_ENABLE_MIDI=<FL_BRIDGE_ENABLE_MIDI> -e FL_BRIDGE_MIDI_PORT=<FL_BRIDGE_MIDI_PORT> -e FL_STUDIO_USER_DATA_DIR=<FL_STUDIO_USER_DATA_DIR> postfader uvx postfader-fl-studio-mcpReplace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from postfader-fl-studio-mcp <command>
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about PostFader
How do I install PostFader in Claude Code?
Run `claude mcp add postfader-fl-studio-mcp -e FL_BRIDGE_ENABLE_MIDI=<FL_BRIDGE_ENABLE_MIDI> -e FL_BRIDGE_MIDI_PORT=<FL_BRIDGE_MIDI_PORT> -e FL_STUDIO_USER_DATA_DIR=<FL_STUDIO_USER_DATA_DIR> -- uvx postfader-fl-studio-mcp` in your terminal. You must configure your virtual MIDI port in FL Studio before connecting.
What does PostFader do?
It lets MCP clients inspect and manipulate an open FL Studio session, supporting mixer adjustments, sound selection, MIDI generation, and exported mix analysis.
Can PostFader overwrite or damage an existing session?
It initializes in read-only mode and never invokes project saving commands. FL Studio undo history remains intact, while every applied parameter change gets read back from the DAW.
