Capsomnia

Capsomnia is a small macOS utility that turns the Caps Lock key into a physical keep awake switch. With Caps Lock on, it disables system sleep so a MacBook keeps working with the lid closed; with Caps Lock off, normal sleep behaviour returns. The Caps Lock light doubles as a status indicator, so you can see at a glance whether sleep prevention is active. It is made for developers who leave long jobs running unattended, particularly AI coding agents such as Codex or Claude Code working through lengthy tasks. The same switch keeps SSH sessions reachable when remote login and networking are available, lets long compiles and large downloads finish, and keeps mobile agent sessions connected. An auto off timer offers presets from 15 minutes to eight hours or a custom duration from one minute to 24 hours; when it ends, Capsomnia releases sleep prevention, confirms it, and puts the Mac to sleep. Anyone already using Caps Lock for something else can assign a different shortcut. Capsomnia is completely free and released under the MIT License. The site invites optional support for the project, but no paid tier is published. The security model is documented in detail. The menu bar app runs as the current user, never as root, and changes sleep settings through one small root owned helper that sudo is permitted to run for exactly three fixed commands. The app makes no network requests, collects no telemetry and has no accounts. It requires macOS 14 or later.