I just wrote a Chrome extension to do it: https://overmod.org/

But tbh this is trivial to write these days since the boilerplate can be written by the machines and you can just write the core functionality to make it work. I only have it public because I'm hoping others will also block users who misinform as a habit and I can subscribe to their lists and crib off their work without having to do it myself.

If you want to save yourself the first 15 min of prompting, just point Claude Code at this https://github.com/TechnologyBrotherhood/overmod-extension and ask it to implement the local blocking functionality.