I asked ChatGPT if there was a macOS setting or free app for this. It couldn't find one that did exactly what I wanted, so I asked it to prototype one. It built a working version in one go.
I then used Codex to add sensible defaults, focus protection, an optional display border, packaging, documentation, an MPL 2.0 license, a logo, and screenshots.
ScreenFocus is the result: keyboard focus follows the pointer across displays while global shortcuts keep working.
This was my first native Mac app, and I used GPT-5.6 Sol with High reasoning. If you check out the README, help docs, and other Markdown files, you might be surprised by how complete it feels.
I also added Launch at Login, full-border and corner-marker styles, custom colors, automatic pausing when only one monitor is connected, and a few other settings.