A bookmarklet would be better. It could achieve the same functionality without the security issues of an extension.
And it would just have to be a single line that you can read so you can trust it. Something like:
javascript:location.href='https://discuss.com/'+location.href
That would redirect you to discuss.com where you can discuss your current url without discuss.com having any access to your data.To make it more convenient, the bookmarklet could also add the discussion to the current page via an iframe which also has no access to any outside data.
This can be done already:
javascript:location.href='https://comntr.github.io/#'+location.href