System monitoring
CPU, GPU, memory, power, temperatures, and the app's own memory footprint.
Your Mac
in one place
System health, external brightness, scheduled locking, mouse tools, and Codex usage in one quiet menu bar panel.
Apple Silicon · macOS 26+ · macOS 27 verifiedCPU: 14%
System 7%User 7%Idle 86%Temp 48°C
UMA: 58%
Used 13.8 GBPressure NormalCompressed 1.42 GBApp 108 MB
Codex Limits: Plus
5H 76%Week 81%
Display: External 1⌄
▱Retina DisplayRestoreBuilt-in · Off
▭PG271QExternalDDC 0 · 15%
More than metrics
Make the little things you do every day feel natural
Interactive demo
Tap a feature and see it work
01
Brightness keys follow your pointer
F1/F2 targets the controllable display under the pointer and passes back to macOS on the built-in display.
- Per-display DDC circuit breaker
- Automatic hot-plug refresh
- Native brightness OSD
02
Lock directly, right on time
Give different parts of the day their own idle limits, including schedules that cross midnight, without starting a screen saver first.
- Reads system lock settings
- Supports next-day times such as 25:00
- Pause any schedule independently
03
Mouse tools load only when needed
Read MX Anywhere 3S DPI, battery, and buttons without keeping HID++ busy in the background.
- DPI input and presets
- Recorded custom shortcuts
- Power-saving reads
04
Usage at a glance
Refresh Codex usage when the panel opens, then follow your chosen interval for 5H and weekly limits.
- Plan and remaining quota
- Separate reset times
- No requests while hidden
↖
Current targetPG271Q
Sunday
00:00 — 07:00Lock after 5 idle minutes
07:00 — 24:00Lock after 20 idle minutes
✓
Policy savedThe active rule locks directly to the login screen
MX Anywhere 3SConnected · Battery 95%
›_
Codex Limits: PlusUpdated just now
5H remaining76%
Weekly remaining81%
Features
One panel, less interruption
Do the necessary work by default. Load heavier data only when its feature is visible or enabled.
External displays
Pointer-aware F1/F2, a single-display header meter, DDC hardware zero, and clear failure reasons.
Scheduled locking
Switch idle limits throughout the day, lock directly, and support schedules across midnight.
On-demand work
DDC, HID, battery telemetry, and Codex only run when needed.
Hidden means pausedDisabled modules stop sampling
Device isolationOne DDC failure does not block other displays
Visible overheadSee the app's memory footprint in the panel
Q&A
Common questions
The things people usually ask before installing
Why does it need Accessibility permission?＋
F1/F2 takeover and mouse button mapping need access to system input events. Fanshu Monitor only uses this access while those features are enabled and does not record keyboard content.
Can it control every external display?＋
The display, cable, and connection must support DDC/CI. Each display is classified independently, with a clear reason when control is unavailable.
Will it use a lot of CPU in the background?＋
Hidden modules stop sampling. Expensive reads such as DDC, HID, and battery telemetry run on demand and use caches.
Does scheduled locking start the screen saver first?＋
No. When a schedule is active, the app requests the system login lock directly and resumes policy evaluation after login.
Which Macs are supported?＋
The current release targets Apple Silicon Macs running macOS 26.0 or later and has been build- and launch-verified on macOS 27.0.
Is it free?＋
Fanshu Monitor is free and open source under the MIT License.
Let your menu bar handle the details
Free and open source. Requires Apple Silicon and macOS 26 or later.