At WWDC26, Apple made a move that most coverage missed. They didn't just update the Foundation Models framework with new models. They restructured it into something closer to a model abstraction layer, one where your Swift code stays the same whether you're calling an on-device model, Apple's Private Cloud Compute, or a third-party provider like Claude or Gemini. That changes the architecture of iOS AI apps significantly. What Actually Changed The Foundation Models framework has existed since Apple Intelligence launched. But until now, it was essentially one thing: an on-device Apple model you called from Swift, with the privacy and latency benefits that come from never leaving the device. WWDC26 turned that into three distinct tiers accessible through one API: The existing on-device model (fast, private, capability-constrained) A new Private Cloud Compute model (bigger, reasoning-capable, 32K token context window) Third-party models including Claude and Gemini, cal...