Foundry IQ's pitch is that your agents get one endpoint for grounded, cited, multi-source context instead of a hand-rolled retrieval stack. What doesn't get talked about enough is that "one endpoint" is a bit of a simplification. Underneath it, you're actually managing four separate auth surfaces that don't share a security model: the control plane you use to provision resources, the per-knowledge-source credentials that vary by source kind, the connection auth between a knowledge base and the agent that calls it, and, the one people get wrong most often, whether the content itself respects the permissions of the person asking.Get any one of these wrong, and you usually don't get an error. You get an agent that confidently answers questions using data the requesting user was never supposed to see. This is a hands-on guide to standing up a real Foundry IQ deployment, knowledge sources, a knowledge base, and both a Foundry Agent and a Microsoft Agent Framework agent grounded against it, built around getting each of those four auth surfaces right instead of defaulting to the admin key that makes the quickstart work.