fuji-mak/Capsomnia

What it solves

Capsomnia prevents MacBooks from sleeping when the lid is closed, solving the problem where standard sleep-prevention tools (like caffeinate) often fail to keep local processes running during closed-lid use. This is particularly useful for maintaining the operation of AI agents, long-running scripts, and remote access sessions.

How it works

It transforms the physical Caps Lock key into a hardware switch for sleep prevention. When Caps Lock is turned on, the app uses a privileged native helper to disable system sleep. It can also optionally prevent the Caps Lock key from actually typing in all-caps and can keep the display awake for remote UI operations. A built-in timer can be set to automatically disable sleep prevention and put the Mac to sleep after a specific duration.

Who it’s for

Developers and power users who run AI coding agents, SSH sessions, large builds, or unattended scripts on a MacBook and need those tasks to continue running while the laptop lid is closed.

Highlights

• Physical Indicator: Uses the Caps Lock LED to provide a clear visual cue of whether sleep prevention is active.
• Closed-Lid Support: Specifically designed to keep work running even when the lid is closed, unlike basic idle-sleep preventers.
• Auto-off Timer: Includes presets (15m to 8h) or custom durations to ensure the Mac eventually sleeps.
• Privacy-focused: Does not make network requests, collect telemetry, or require an account.