Mos
Mos is a free macOS menu bar utility from Caldis that makes mouse-wheel scrolling smoother and adds advanced mouse button actions.
What is Mos?
Mos is a macOS utility published by Caldis that changes how external mouse scrolling feels on a Mac. Its main purpose is to smooth mouse-wheel input so scrolling behaves more like a trackpad, while still allowing precise control and per-app customization. It also includes options for reversing scroll direction, tuning vertical and horizontal scroll behavior independently, and assigning actions or shortcuts to mouse buttons. Mos integrates with macOS accessibility features because it needs permission to observe and rewrite input events. Users commonly encounter it after installing a third-party mouse utility to improve scrolling in browsers, editors, design apps, or productivity tools. It is distributed as a local menu bar app and is also available through Homebrew, with project documentation and releases maintained by Caldis.
Key features
- Smooths mouse-wheel scrolling to feel closer to a trackpad
- Supports per-app scroll profiles and behavior overrides
- Lets you tune vertical and horizontal scrolling independently
- Can reverse scroll direction separately from other input devices
- Binds mouse buttons to shortcuts, apps, scripts, or system actions
- Works as a menu bar utility for quick access to settings
- Supports Logitech HID++ button handling for some devices
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Safety overview
Status: Mostly safe
Mos is a legitimate local input utility, but it requires Accessibility permission to read and modify mouse input events. That level of access is expected for its function, yet it means you should only keep it if you installed it intentionally and trust the source.
Recommendation: Keep Mos if you use a mouse on macOS and want smoother scrolling or custom button behavior. Remove it if you no longer need those features or do not want to grant Accessibility access to a third-party input tool.
Common paths
/Applications/Mos.app
Support paths
~/Library/Application Support/com.caldis.Mos
Preference paths
~/Library/Preferences/com.caldis.Mos.plist
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