Foundation Models Framework — Complete API Reference

Overview

The Foundation Models framework provides access to Apple's on-device Large Language Model (3 billion parameters, 2-bit quantized) with a Swift API. This reference covers every API, all WWDC 2025 code examples, and comprehensive implementation patterns.

Model Specifications

3B parameter model, 2-bit quantized, 4096 token context (input + output combined). Optimized for on-device summarization, extraction, classification, and generation. NOT suited for world knowledge, complex reasoning, math, or translation. Runs entirely on-device — no network, no cost, no data leaves device.

When to Use This Reference