Automate external monitor brightness with Mac Shortcuts
If your desk changes between work, night, calls, and another input source, Shortcuts can trigger the display state instead of sending you back through monitor buttons.
Use Mac Shortcuts for external monitor brightness when the same display change happens often enough to name: lower every external monitor at night, apply a Work preset in the morning, switch an input before using another computer, or set a presentation desk state before a call.
TeenyDisplay supports this through a teenydisplay:// URL scheme. Shortcuts can open URLs, and Apple documents URL schemes as a way for apps and shortcuts to call into one another. TeenyDisplay listens for those URLs and turns them into display commands.
The boundary is important. URL automation can only control displays and settings TeenyDisplay can reach. If a monitor does not expose DDC brightness, TeenyDisplay may use software dimming, but software dimming is not panel backlight control.
Quick command table
| Goal | URL example | Use it when... |
|---|---|---|
| Set every display to 75% | teenydisplay://brightness?display=all&value=75 |
You want one known brightness level. |
| Dim external displays by 10% | teenydisplay://brightness?display=external&delta=-10 |
The room got darker and the desk needs a small move. |
| Apply a Work preset | teenydisplay://preset?name=Work |
Several display settings should change together. |
| Switch input | teenydisplay://input?display=1&value=17 |
Your monitor exposes input switching through DDC. |
| Read display info | teenydisplay://info |
You want a read-only diagnostic command. |
How the URL scheme works
The TeenyDisplay source defines URL commands for brightness, contrast, volume, input, power, preset, and info. The display parameter can be a one-based display number, all, external, or omitted. When omitted, the command targets all displays the command can address.
Brightness accepts either a fixed value from 0 to 100 or a delta such as -10. Presets accept a name. Input and power commands depend on what the monitor exposes over DDC.
State-changing commands require active TeenyDisplay access in the source. The read-only info command is allowed without full access. That is a sensible split: diagnostics can be open, but commands that change hardware state should respect the app's license and trial state.
Build the Shortcuts action
- Open Shortcuts on your Mac.
- Create a new shortcut named for the desk state, such as Night Desk.
- Add the URL text, for example
teenydisplay://brightness?display=external&delta=-10. - Add an Open URL action.
- Run it once while TeenyDisplay is installed and allowed to control your displays.
- Optional: assign a keyboard shortcut, add it to the menu bar, or call it from another shortcut.
Apple's own guidance is useful here: URL schemes can be opened from apps, browsers, command-line contexts, and Shortcuts. Keep each command small. If you need several commands, put them in a named shortcut so you can test and edit the steps later.
Use presets for real desk states
Brightness commands are good for small changes. Presets are better when the desk has a real mode.
The preset source saves one entry per display, including brightness, contrast, volume, input source, resolution, refresh rate, and HiDPI state where those values are available. When a preset is applied, TeenyDisplay matches saved entries to connected displays and skips displays that are not present.
That makes teenydisplay://preset?name=Work a stronger automation than five separate brightness and input commands. It names the outcome. The deeper preset guide is Mac display presets for external monitors.
Where automation fails
First, the monitor has to expose the control. DDC brightness, contrast, volume, power, and input support vary by display and connection. TeenyDisplay supports USB-C, Thunderbolt, HDMI, DisplayPort, and DVI where the display path exposes control, and it has software dimming as a fallback for brightness. It still cannot force a monitor to expose a feature the hardware hides.
Second, URL commands are easy to mistype. Test with one monitor before sending commands to all. Keep preset names plain. Avoid storing secrets or private text in URL strings because URLs can be logged by the tool that launches them.
Third, Shortcuts is glue, not proof. If a display state matters for a recording, presentation, or client call, run the shortcut and look at the screen. A desk automation should save clicks, not remove judgment.
Common questions
Can Mac Shortcuts change external monitor brightness?
Shortcuts can open URL schemes. TeenyDisplay adds teenydisplay:// commands that can change brightness on supported displays, so a shortcut can trigger those commands.
Does TeenyDisplay automation require a license?
State-changing URL commands require active TeenyDisplay access. The source allows the read-only info command without a license.
Will brightness automation work on every monitor?
No. Hardware brightness depends on what the display and connection expose through DDC. TeenyDisplay can fall back to software dimming when DDC brightness is unavailable, but that is not the same as panel backlight control.
Sources checked
- TeenyDisplay feature claims were checked against the local homepage and source files for
CLIHandler, URL commands, display targets, brightness controls, presets, license checks, and software dimming. - TeenyDisplay homepage for current pricing, trial, feature list, URL scheme examples, and macOS compatibility.
- Apple Support: Run a shortcut using a URL scheme on Mac.
- Apple Support: Run a shortcut while working on your Mac.
- Apple Support: Intro to URL schemes in Shortcuts on Mac.
Automate the display states you actually use.
teenydisplay is a $9.99 Mac menu bar app for external monitor brightness, contrast, volume, input source, presets, shortcuts, software dimming, and URL automation.