Plug

Plug runs the sound your Mac plays through Audio Unit effects, and plays the result to the output you choose. It needs macOS 14.2 or later.

Install

1. Open the Plug disk image and drag Plug onto Applications.
2. The first time, right-click Plug in Applications and choose Open, then Open again. After that, open it as usual.
3. When you first press START, macOS asks to allow System Audio Recording. Allow it.

Play

• START (green) plays. STOP (red) stops. The lit lamp shows which is active.
• While Plug plays, the sound it captures is heard only through Plug. Press STOP and other apps play normally again.
• Keep your volume low at first. The master knob can boost.

Choose what goes in: INPUT

Click the INPUT knob and pick one:

• Test tone: a quiet tone, for trying effects.
• System audio: everything your Mac plays.
• Apps: only the apps you tick in the drawer. Click the arrow to refresh the list. An app opened while Plug is playing joins at the next STOP and START.

Choose where it plays: OUTPUT

Click the OUTPUT knob and pick a speaker, headphones or interface. Choose Refresh devices if one is missing.

Effects

• Add: click the ADD knob and pick an effect.
• Order: drag effects up or down in the drawer. Sound passes through them top to bottom.
• Bypass: switches an effect off but keeps its settings.
• Sliders icon: opens the effect's controls.
• Bin: removes the effect.

The worn handle in the bottom strip opens and closes the drawer.

Master volume

• Drag the MASTER knob up or down.
• The bent tack marks 0 dB. Click the tack to return there.
• Below the tack turns the level down. Above it boosts, up to +10 dB. Too much boost distorts.

MIDI control

1. Click MIDI LEARN.
2. Move a knob or fader on your MIDI controller.
3. That control now turns the master knob.

Right-click MIDI LEARN to forget the control.

Buttons

Add your own buttons to the menu bar panel. Each one does a single thing when you click it.

1. Click the VU meter in the menu bar, then Add Buttons… (or choose Plug > Settings…).
2. Click + and pick what the button does. Give it a name and an icon.
3. Click Try It to test it. Every change is saved as you make it.

A button can:

• Plug control: Start or Stop, recall a preset, set the master level, or bypass an effect.
• Send MIDI: a control change, note or program change, to one MIDI output or all of them. To reach another app on this Mac, turn on the IAC Driver in Audio MIDI Setup.
• Run command: a Terminal command, run from your home folder.
• Run shortcut: any shortcut from the Shortcuts app, by name.
• Open: a web address, file, folder or app.
• Ask Claude: sends your prompt to Claude Code on this Mac and shows the reply. Install Claude Code and run claude once in Terminal to sign in first.
  • Start the prompt with / to run a slash command or skill, such as /run.
  • Folder is where Claude starts, so it uses that project's commands, skills and notes. Leave it empty for your home folder.
  • Claude may sets what it can do there: read and answer only, or also edit files.
  • Also allow names commands it may run, separated by commas, such as Bash(swift test),Bash(scripts/bundle.sh). Nobody is there to approve anything, so Claude is refused whatever isn't allowed.

Example: send a message to a Claude cloud session

A Run command button can hand a prompt to one of your Claude Code sessions on claude.ai, so the work runs there instead of on this Mac:

1. Open the session on claude.ai and copy its ID from the address bar: the part starting session_.
2. Make a Run command button with the command: claude -p "Your prompt here" --cloud session_YOUR_SESSION_ID
3. Tick Show the result in a window.

Clicking it shows Sent to cloud session. in a few seconds. The session then works on the prompt, and you read the result there. Claude Code on this Mac must be signed in to the same Claude account as the session, and the session must not be archived.

Tick Show the result in a window to see what a command printed. Click a button while it's still running to stop it. Drag buttons in the list to change their order, and select one and click – (or press Delete, or right-click it and choose Delete) to remove it.

Presets

• SAVE stores everything: input, apps, output, effects with their settings, and the master level.
• Click the small preset knob to recall a preset, or click the bin beside it to delete it.

Quick controls

• Dock icon, right-click: Start or Stop, and set the master level.
• VU meter in the menu bar: a master volume slider, your buttons, Start or Stop, Open Plug, and Quit.

Closing the window keeps Plug playing. Quit Plug to stop it completely.

Help and updates

• Help > Plug Help opens this guide.
• Plug > Check for Updates… tells you if a newer Plug is available.

If you hear nothing

• Allow Plug in System Settings > Privacy & Security > Screen & System Audio Recording, then press STOP and START.
• Check the MASTER knob isn't turned all the way down.
• Check OUTPUT is set to where you're listening.
• With Apps, check the app is ticked and was open when you pressed START.