foundation-models

Q: How do I install foundation-models?

Run npx skills add https://github.com/johnrogers/claude-swift-engineering --skill foundation-models in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/foundation-models/ (personal) or .claude/skills/foundation-models/ (project).

by johnrogersMobile

Use when implementing on-device AI with Apple's Foundation Models framework (iOS 26+), building summarization/extraction/classification features, or using @Generable for type-safe structured output.

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Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/johnrogers/claude-swift-engineering --skill foundation-models

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads foundation-models automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Foundation Models

Apple's on-device AI framework providing access to a 3B parameter language model for summarization, extraction, classification, and content generation. Runs entirely on-device with no network required.

Overview

Foundation Models enable intelligent text processing directly on device without server round-trips, user data sharing, or network dependencies. The core principle: leverage on-device AI for specific, contained tasks (not for general knowledge).

Reference Loading Guide

ALWAYS load reference files if there is even a small chance the content may be required. It's better to have the context than to miss a pattern or make a mistake.

Reference	Load When
Getting Started	Setting up LanguageModelSession, checking availability, basic prompts
Structured Output	Using `@Generable` for type-safe responses, `@Guide` constraints
Tool Calling	Integrating external data (weather, contacts, MapKit) via Tool protocol
Streaming	AsyncSequence for progressive UI updates, PartiallyGenerated types
Troubleshooting	Context overflow, guardrails, errors, anti-patterns

Core Workflow

Check availability with SystemLanguageModel.default.availability
Create LanguageModelSession with optional instructions
Choose output type: plain String or @Generable struct
Use streaming for long generations (>1 second)
Handle errors: context overflow, guardrails, unsupported language

Model Capabilities

Use Case	Foundation Models?	Alternative
Summarization	Yes	-
Extraction (key info)	Yes	-
Classification	Yes	-
Content tagging	Yes (built-in adapter)	-
World knowledge	No	ChatGPT, Claude, Gemini
Complex reasoning	No	Server LLMs

Platform Requirements

iOS 26+, macOS 26+, iPadOS 26+, visionOS 26+
Apple Intelligence-enabled device (iPhone 15 Pro+, M1+ iPad/Mac)
User opted into Apple Intelligence

Common Mistakes

Using Foundation Models for world knowledge — The 3B model is trained for on-device tasks only. It won't know current events, specific facts, or "who is X". Use ChatGPT/Claude for that. Keep prompts to: summarizing user's own content, extracting info, classifying text.
Blocking the main thread — LanguageModelSession calls must run on a background thread or async context. Blocking the main thread locks UI. Always use Task { } or background queue.
Ignoring context overflow — The model has finite context. If the user pastes a 50KB document, it will fail silently or truncate. Check input length and trim/truncate proactively.
Forgetting to check availability — Not all devices support Foundation Models. Check SystemLanguageModel.default.availability before using. Graceful degradation is required.
Ignoring guardrails — The model won't answer harmful queries. Instead of fighting it, design prompts that respect safety guidelines. Rephrasing requests usually works.

FAQ

What does the foundation-models skill do?

Use when implementing on-device AI with Apple's Foundation Models framework (iOS 26+), building summarization/extraction/classification features, or using @Generable for type-safe structured output.

How do I install foundation-models?

Run npx skills add https://github.com/johnrogers/claude-swift-engineering --skill foundation-models in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/foundation-models/ (personal) or .claude/skills/foundation-models/ (project).

Which AI agents can use foundation-models?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is foundation-models safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains foundation-models?

It is published by johnrogers in johnrogers/claude-swift-engineering. It has 152 recorded installs.