foundation-models

Foundation Models

APPLE ON-DEVICE AI (FoundationModels — iOS 26+): FRAMEWORK: import FoundationModels

AVAILABILITY CHECK (MANDATORY — model may not be available on all devices): guard case .available = SystemLanguageModel.default.availability else { // Show "This feature requires Apple Intelligence" message return }

BASIC TEXT GENERATION: let session = LanguageModelSession() let response = try await session.respond(to: "Summarize this text: (userText)") print(response.content)

STREAMING GENERATION: let stream = session.streamResponse(to: prompt) for try await partial in stream { displayText += partial.text }

STRUCTURED OUTPUT with @Generable: @Generable struct RecipeSuggestion { @Guide(description: "Name of the dish") var name: String @Guide(description: "Estimated prep time in minutes") var prepTime: Int @Guide(description: "Main ingredients") var ingredients: [String] }

let session = LanguageModelSession() let recipe: RecipeSuggestion = try await session.respond( to: "Suggest a quick pasta dish", generating: RecipeSuggestion.self )

SESSION INSTRUCTIONS (system prompt): let session = LanguageModelSession(instructions: "You are a helpful cooking assistant. Keep responses concise.")

GUARDRAILS:

• Model output is filtered by Apple's safety system
• No internet required — fully on-device
• Context window is limited (~4K tokens typical) — keep prompts concise
• Use session.respond() for single turns, keep session for multi-turn conversations