free-clamshell-mode

 _______ .______       _______  _______          ______  __          ___      .___  ___.      _______. __    __   _______  __       __             .___  ___.   ______    _______   _______ 
|   ____||   _  \     |   ____||   ____|        /      ||  |        /   \     |   \/   |     /       ||  |  |  | |   ____||  |     |  |            |   \/   |  /  __  \  |       \ |   ____|
|  |__   |  |_)  |    |  |__   |  |__    ______|  ,----'|  |       /  ^  \    |  \  /  |    |   (----`|  |__|  | |  |__   |  |     |  |      ______|  \  /  | |  |  |  | |  .--.  ||  |__   
|   __|  |      /     |   __|  |   __|  |______|  |     |  |      /  /_\  \   |  |\/|  |     \   \    |   __   | |   __|  |  |     |  |     |______|  |\/|  | |  |  |  | |  |  |  ||   __|  
|  |     |  |\  \----.|  |____ |  |____        |  `----.|  `----./  _____  \  |  |  |  | .----)   |   |  |  |  | |  |____ |  `----.|  `----.       |  |  |  | |  `--'  | |  '--'  ||  |____ 
|__|     | _| `._____||_______||_______|        \______||_______/__/     \__\ |__|  |__| |_______/    |__|  |__| |_______||_______||_______|       |__|  |__|  \______/  |_______/ |_______|
                                                                                                                                                                                            

Minimal macOS menu bar app that keeps your Mac awake with the lid closed — no AC power required.

Build

bash build.sh

Output: build/free-clamshell-mode.app

Install (optional)

cp -r build/free-clamshell-mode.app ~/Applications/

Then open the app and enable Settings > Launch at Login.

Usage

1. Build and open the app
2. Clam shell icon appears in the menu bar
3. Left-click the icon to toggle on/off
4. Right-click (or Ctrl+click) to open the menu

The icon turns into a green scallop fan when active.

How It Works

Uses sudo pmset -a disablesleep 1 to prevent the system from sleeping when the lid is closed, regardless of power source.

State	Command
Enable	sudo pmset -a disablesleep 1
Disable	sudo pmset -a disablesleep 0

Admin Password — First Time Only

On first activation the app writes a sudoers rule so pmset can run password-free on all future uses:

/etc/sudoers.d/free-clamshell-mode
<username> ALL=(ALL) NOPASSWD: /usr/bin/pmset

You will see a macOS admin password dialog once. After that, no password is ever needed again — even after restarts.

To remove this permission manually:

sudo rm /etc/sudoers.d/free-clamshell-mode

Settings

Setting	Default	Description
Launch at Login	Off	Auto-start on login via SMAppService
Hide from Dock	On	App appears only in the menu bar
Show Warnings	On	Confirm dialog before enabling

Important: Force Quit Behavior

If the app is force-quit while active, disablesleep remains set to 1. Restore normal sleep behavior manually:

sudo pmset -a disablesleep 0

A clean quit (Cmd+Q or Quit from the menu) always resets disablesleep to 0 automatically.

Troubleshooting

macOS blocks app after rebuild (code signature mismatch):

codesign --remove-signature build/free-clamshell-mode.app

"Permission denied":

chmod +x build/free-clamshell-mode.app/Contents/MacOS/free-clamshell-mode

"Compilation failed":

xcode-select --install

pmset disablesleep stuck at 1:

sudo pmset -a disablesleep 0