If you're getting an indication that the answer came from the KB but it's a useless non-answer then you may need to change the 'description' of your KB to tell what it is or is not used for and possibly remove some of the not-useful knowledge that it is using to respond with. That's the possible easy solution. But likely you will also want to disable automatic answering from the knowledge agent, and rely on the 'Query Knowledge Bases' card to give more control over what is asked. Then you can query the variable {{turn.KnowledgeAgent.answer}} to see if the KB lookup was successful or not and proceed however you like from there.