I Built a Pneumonia Detection AI on My MacBook — Here's Exactly How It Works

I just finished building a deep learning system that identifies pneumonia from chest X-rays with 96% accuracy and an AUC-ROC of 0.99. I ran the entire training process on my MacBook Pro M5 using the GPU acceleration provided by Apple's Metal Performance Shaders (MPS). This project wasn't about complex math; it was about using transfer learning to turn a consumer laptop into a medical diagnostic tool. Understanding how to handle messy data and verify what an AI is actually "seeing" is more import