FoundationModels: On-Device LLM (iOS 26) Patterns for integrating Apple's on-device language model into apps using the FoundationModels framework. Covers text generation, structured output with , custom tool calling, and snapshot streaming — all running on-device for privacy and offline support. When to Activate - Building AI-powered features using Apple Intelligence on-device - Generating or summarizing text without cloud dependency - Extracting structured data from natural language input - Implementing custom tool calling for domain-specific AI actions - Streaming structured responses for r…