iPhone Duo Skills

Image © Apple Inc., from the iPhone Duo developer page, used for identification. Not affiliated with or endorsed by Apple.

Agent skills for building iOS apps on iPhone Duo — Apple's first foldable iPhone, announced September 9, 2026.

Apple's developer material for iPhone Duo is six Tech Talk videos plus the Designing for iPhone Duo HIG page. Xcode 27.1 and the Preparing your app for iPhone Duo article are still listed as coming. These skills distill what exists into structured guidance an agent can act on, plus reference sheets for device facts and the full API surface.

Install

npx skills add mirzaaghazadeh/iphone-duo-skills

Installs all nine. The CLI detects your agent — Claude Code, Cursor, Copilot, Gemini and others — and puts them where that agent looks.

Useful flags:

# just one skill
npx skills add mirzaaghazadeh/iphone-duo-skills --skill iphone-duo-readiness

# user-level instead of project-level
npx skills add mirzaaghazadeh/iphone-duo-skills --global

# see what's in here without installing
npx skills add mirzaaghazadeh/iphone-duo-skills --list

To try a skill without installing it at all:

npx skills use mirzaaghazadeh/iphone-duo-skills@iphone-duo-readiness

git clone https://github.com/mirzaaghazadeh/iphone-duo-skills.git
cp -r iphone-duo-skills/skills/* ~/.claude/skills/

Or project-level, into .claude/skills/ in a repo.

Each skill is a self-contained SKILL.md with YAML frontmatter, so it also works anywhere that reads plain Markdown instructions. Restart the session and the skills appear; invoke one by name or just describe the task.

The skills

Which skills apply to your stack

Native iOS — SwiftUI or UIKit. Start with iphone-duo-readiness, which routes you to the rest. The five Swift-focused skills name real iOS 27.1 APIs you can call directly; iphone-duo-design-review applies whatever you build in.

Flutter. Read iphone-duo-flutter first, then iphone-duo-design-review — the design guidance is framework-neutral and applies unchanged. Skim iphone-duo-adaptive-layout for the reasoning behind reserved regions and displacement; the concepts transfer even though the code doesn't.

React Native or Expo. Same shape: iphone-duo-react-native, then iphone-duo-design-review, then iphone-duo-adaptive-layout for background.

Any framework, if you capture photo or video. iphone-duo-camera matters regardless of stack, because the two front cameras and the "which way is this camera facing" problem are AVFoundation-level facts. Cross-platform apps hit them through whatever camera plugin they use, or through their own bridge.

Games — Unity, Unreal, Godot, SpriteKit, Metal. Read iphone-duo-games. Games sidestep most of the UI guidance but not resizing, and the fold is a genuine hazard for on-screen touch controls.

Kotlin Multiplatform, .NET MAUI, Capacitor and friends. No dedicated skill, but the pattern from the Flutter and React Native skills carries over directly: everything is either resize and safe-area handling you can do in your existing layer, or a native bridge to the iOS 27.1 APIs. Read whichever cross-platform skill is closer to your setup, plus iphone-duo-design-review.

Cross-platform reality check. Neither Flutter nor React Native supports iPhone Duo yet. Flutter's MediaQuery.displayFeatures is documented as populated only on Android, so it returns an empty list here; React Native has no fold API at all. Both skills split what works today from what needs a native bridge, so you don't lose an afternoon hunting for an API that isn't there.

Reference

• reference/device-facts.md — displays, silicon, cameras, poses, and the size-class table
• reference/api-index.md — every announced API by job, with framework and minimum SDK
• reference/sources.md — every source, linked

What actually matters on this device

If you read nothing else:

iPhone Duo is not a new idiom — it's a wider continuum of sizes. Every bug in a foldable port comes from an app asserting something fixed (this idiom, this orientation, this screen, this width, this symmetric inset), and every fix replaces that assertion with a question about the space available right now.

Diagram by this project. The underlying behavior is documented across Apple's iPhone Duo Tech Talks and Designing for iPhone Duo; see reference/sources.md.

Three concrete consequences:

1. The inner display ignores your supported interface orientations. Branch on size class, never on orientation or idiom.
2. UIScreen.main is ambiguous here and slated for deprecation. Use the environment, the trait collection, or the scene's bounds.
3. Safe areas are asymmetric. Any math shaped like width - safeAreaInsets.left * 2 is a defect.

And the highest-leverage single change: build against the iOS 27.1 SDK. It's the gate for edge-to-edge content, vertical bars, reserved regions and arrangements.

Accuracy

Every technical claim traces to Apple's Tech Talks, the Designing for iPhone Duo HIG page, or the Newsroom announcement. Nothing is invented — but most of these APIs were announced while Xcode 27.1 was still rolling out, so treat the names as the shape of the API and confirm exact signatures against the SDK headers before relying on a build.

A handful of toolbar API names are now confirmed by the published HIG; reference/api-index.md marks which ones.

scripts/fetch-transcripts.py re-fetches the Tech Talk transcripts from the WebVTT subtitle track in each video's HLS manifest, which is how this repo was researched. Re-run it when Xcode 27.1 ships and the pending documentation lands.

License

MIT — see LICENSE.

Not affiliated with or endorsed by Apple. "iPhone" and "iPhone Duo" are trademarks of Apple Inc.