There are multiple funny settings in Copilot Studio bot. Same stuff needs to be done many times, and there are multiple combinations for setting up knowledge source and generative AI replies. Reason is that you might want to have replies only based on your knowledge base, not based on ChatGPT mambo-jumbo. I figured these out and tested when searching solution why out-of-the-box Teams and Power Apps authentication does not give results from SharePoint site.
Cannot find SharePoint site content
Reason for my initial problem was Conditional Access App Control of Microsoft Defender for Cloud App adding .mcas.ms in the end of a SharePoint site url. When adding that url to Copilot Studio bot knowledge source, it cannot find answer to questions.
Restrict generative AI replies
You can turn them off in general level from all places on the Overview page
But you can still turn it on in the settings, weird – better leave this to Classic if you wish to get replies only based on your knowledge source meaning SharePoint site and not ChatGPT hallucination.
But then you still need go to Topics and select Conversational boosting topic from system tab. If you disabled gen AI features on Overview page, then it is disabled here. You could also leave it on and disable it here, if you wish to use it in your own custom topic.
And then there is possibility to add still more sites on top of those which you have set in the knowledge settings for the Copilot Studio bot.