I've made a Chrome extension that only allows a single tab in a browser window in an attempt to regain my focus when browsing the web and more generally, when sitting behind my computer (which is a lot).
What it does:
-Opening a new tab with the '+' button or keyboard shortcut will not work.
-Opening a link in a new tab will open the link in the current tab instead.
I have tested this on Chrome and Brave.
Writing browser extensions is not my forte, I have made this using Claude Code. It will contain bugs, feel free to submit a PR at https://github.com/MathieuBordere/onetabman
Try it out and let me know what you think!