Search Kagi with a bang, such as g!. The search results redirect back to Kagi if the extension is set to redirect all search engines. Even a search on Google.com redirects to Kagi.
My expectations for this extension are that it allows me to search from the address bar, since I can't choose Kagi in the Safari settings. But if I want to search Google - which I do for shopping - I can't get to Google with a bang. I had to turn off redirect for all search engines, and select one from the list that I will never use.
This does not seem like correct behavior, since redirecting any search engine by the extension should be overridden by a bang.