Mystral

A native macOS menu bar app for controlling fan curves on Apple Silicon Macs.

Features

• Real fan control on Apple Silicon — works on M1/M2/M3/M4 (uses the Ftst unlock to bypass thermalmonitord)
• Menu bar presence — always-on icon with configurable display: temperature, RPM, profile name, or a live mini-graph sparkline
• Live dashboard — Swift Charts 5-minute rolling history of CPU max/avg + GPU max
• Fan curve editor — drag-and-drop chart with synchronized editable table; per-fan curve overrides
• Profiles — 4 presets (Silent, Balanced, Performance, Full Blast) + up to 10 custom; inline rename, duplicate, delete
• Auto-switch — profiles can auto-activate based on power source (AC/Battery), thermal state, or frontmost app
• Smoothing & hysteresis — EMA-smoothed input temperatures + configurable deadband to eliminate fan hunting
• Alerts — optional notifications for high CPU temperature and fans that stop responding
• 30s stress test — burns all CPU cores and verifies your fan curve actually reacts
• Auto-start — launch at login via macOS native login items
• Localization — English and Italian

Requirements

• macOS 14.0 or later
• Apple Silicon Mac (M1, M2, M3, M4, M5)

Installation

1. Download the latest Mystral-x.x.x.dmg from Releases.
2. Open the DMG and drag Mystral.app into the Applications folder.
3. First launch: right-click Mystral.app in /Applications → Open → click Open in the dialog. (This step is needed because the app is not yet signed with a paid Apple Developer ID. Subsequent launches don't require it.)
4. The app will ask for your password once per session to control the fans (no kernel extension required).

That's it. Profiles live in ~/Library/Application Support/Mystral.

Build from Source

brew install xcodegen
git clone https://github.com/fexxdev/Mystral.git
cd Mystral
xcodegen generate
./scripts/build-dmg.sh        # produces dist/Mystral-x.x.x.dmg
# or for development:
open Mystral.xcodeproj

Usage

1. Mystral appears in the menu bar with a fan icon
2. Left click the icon to open the main window
3. Right click for quick profile switching
4. Go to Profiles to create custom fan curves
5. Go to Settings to configure auto-start and display options

Preset Profiles

Profile	Description
Silent	Minimum fan noise, higher temperatures allowed
Balanced	Apple-like default curve
Performance	Aggressive cooling for heavy workloads
Full Blast	All fans at maximum speed

Privacy

Mystral runs entirely offline. No telemetry, no network access, no data collection.

License

MIT — see LICENSE.