Anthropic's Swift package puts Claude inside Apple's Foundation Models framework

Anthropic has published a Swift package, ClaudeForFoundationModels, that makes Claude available through Apple's Foundation Models framework as a server-side language model provider.

The integration works by conforming Claude to Apple's LanguageModel protocol, so iOS and macOS apps can call Claude using the same LanguageModelSession API they use for Apple's on-device model. That means respond(to:), streaming, guided generation, and tool calling all work identically regardless of whether the session is backed by Apple's local model or Claude running remotely. Requests go directly from the device to the Anthropic API; Apple is not in the request path and does not see prompts or responses. Usage is billed to the developer's Anthropic account at standard API rates.

The package targets the Foundation Models server-side API introduced in the iOS 27 and macOS 27 betas, so it is not yet production-ready. The meaningful design decision is that the app, not the framework, decides which model handles each session, making it straightforward to route simple requests to the free on-device model and complex ones to Claude. Whether that trade-off prompts Apple to push back on competing providers sharing its framework API is the obvious open question.