Use Hammerspoon [0][1], it comes with a lot of macOS integrations out of the box and you write Lua, which takes zero effort to pick up and use. For me a big benefit is that you don't need to touch Xcode at all.

[0] https://www.hammerspoon.org

[1] https://www.hammerspoon.org/docs/hs.menubar.html

That is exactly what I did. Claude scaffolded it from scratch based on behaviour, then I iterated and had Codex review it for safety.

Speaking of the macOS menu bar, is there some way to make it overflow into a hidden area behind an "expand" button that would appear when there is no more room, like the notification area in Windows does?

The macOS UI decision of "just pretend that whatever doesn't fit to the right of the notch doesn't exist" is baffling.

I've seen a few apps that claim to do that, but it's always done in some really hacky way (such as needing screen recording permissions), and the behavior is never that of simple overflow handling. Instead they have "always hidden" sections and things like that, which is not what I want.

No template needed IMO.

I used CC just yesterday to build a native MacOS menu bar app by using plan mode (opus) until there was alignment then to edit mode for the build (I use Zed for the prompting).

CC walked me through the needed Xcode project setup and handled all of the code there after.

I’m sure something more complex would be more challenging but I was happy with a two-shot result for this native menu bar app.