wtf is maccheck?

MacCheck is a macOS app for inspecting a Mac's hardware, aimed at people buying or selling a used Mac, repair shops checking devices before resale, and anyone who wants to check their own machine's health. Everything runs locally on the Mac itself, and the app does not upload the serial number, test results, or generated reports anywhere. When opened, MacCheck automatically reads basic information such as the model, chip, memory, macOS version, serial number, and model year. It also checks battery cycle count and health, storage space, network status, Bluetooth, and ports. For a second-hand buyer, it flags high-risk items like whether the device is enrolled in Mobile Device Management, whether Activation Lock is on for the Apple ID, and the state of the security chip. Beyond the automatic checks, MacCheck walks the user through hands-on tests that need a person to confirm: lighting up each keyboard key one by one, showing solid colors, grayscale, and checkerboard patterns on the screen, testing audio playback, the microphone, the camera, Touch ID, and the trackpad. It can also measure disk read and write speed, run a performance stress test, and test each physical port individually. There is also a feature that estimates, based on the Mac's memory, how well it could run local AI models. Once testing is done, the results can be saved as a history entry and exported as a PDF or a long PNG image report, which is useful for documenting the condition of a machine during a sale or trade. The interface supports light, dark, and system-matched appearance. MacCheck requires macOS 14 or later and runs on both Apple Silicon and Intel Macs. It can be installed from a downloadable DMG file, or built from source using Xcode 16, with an optional xcodegen step to regenerate the Xcode project. The README notes that MacCheck is meant to assist with inspection and does not replace Apple's own warranty or official service checks, and that some results depend on Apple's servers or the specific hardware available.