<div align="center">
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<source media="(prefers-color-scheme: dark)" srcset="docs/assets/banner-dark.svg" />
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<img src="docs/assets/banner-light.svg" alt="Duology: design, build, test and ship apps for iPhone Duo with Claude Code" width="100%" />
</picture>
# Duology
### Claude Code skills for designing, building, testing and shipping apps on iPhone Duo.
**Your agent learned iOS before the iPhone Duo existed. Duology teaches it the rest.**
[](https://github.com/Kimeur/duology/stargazers)
[](https://github.com/Kimeur/duology/releases)
[](#whats-inside)
[](#commands-and-agents)
[](#app-recipes)
[](#verified-on)
[](#quick-start)
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[Quick start](#quick-start) · [What's inside](#whats-inside) · [Patterns](#layout-patterns) · [Recipes](#app-recipes) · [Proof](#proof-not-promises) · [FAQ](#faq) · [Roadmap](ROADMAP.md)
<code>/plugin marketplace add Kimeur/duology</code>
</div>
> [!IMPORTANT]
> **v0.4 is out** (29 October 2026): for apps that already ship. `duo-migrate` moves an app to Xcode 27.1 and the scene life cycle step by step, `duo-app-store` makes the App Store screenshots of both displays, and `/duo-ship` checks the April 2027 App Store rules before you submit: it runs your app in every pose, and the `duo-pose-tester` agent reports each failure with its screenshot. Plus a sixth recipe, `recipe-kids-learning`. 33 skills in 5 plugins, 6 commands and 2 agents, checked on Xcode 27.1 and the iPhone Duo simulator. Checks on a real iPhone Duo and published test results come next. Duology is built in the open: the full pack of 36 skills is planned for v1.0 in January 2027. Star or watch the repo to follow along. See the [roadmap](ROADMAP.md) and the [release notes](CHANGELOG.md).
> [!NOTE]
> Duology is a community project. It is not affiliated with, endorsed by or sponsored by Apple Inc.
> iPhone is a trademark of Apple Inc. Every API claim links to Apple's own documentation in [`reference/sources.md`](reference/sources.md).
<div align="center">
<br />
<a href="docs/assets/demo/duology-demo.mp4"><img src="docs/assets/demo/duology-demo.gif" alt="Demo: Claude Code runs duo-lint on an app built before iPhone Duo, fixes the four findings until duo-lint reports zero, then the gallery app is shown closed, open, half folded like a book and propped up in tabletop on the iPhone Duo simulator" width="100%" /></a>
<br />
<sub>25-second demo, silent. <a href="docs/assets/demo/duology-demo.mp4">Watch the MP4</a>. Lint output and screenshots are real.</sub>
<br /><br />
</div>
---
## The problem
iPhone Duo is in stores from 23 October 2026. It has a 5.4″ outer display, a 7.6″ inner display and a fold. Coding agents were trained before it existed, so when you ask one to "make this work on Duo" it writes code Apple tells you not to write:
- it measures `UIScreen.main.bounds`, which is ambiguous on a phone with two displays;
- it branches on device orientation or `userInterfaceIdiom` and treats "regular width" as "iPad";
- it puts buttons and text where the phone folds;
- it rebuilds the screen when you unfold, so you lose your scroll position, your typing or your video;
- it designs one screen and stretches it, instead of a layout for each way people hold the phone.
Apple published the rules in six Tech Talks, a HIG page and the iOS 27.1 SDK. Duology turns them, plus what we learned shipping a real Duo app, into skills Claude Code loads when it needs them.
### How Duology fixes it
1. **It knows the device.** Size classes, reserved regions, `ArrangementView`, vertical bars and the hinge. Each fact is checked against the iOS 27.1 SDK. Scenes and windows have their own skill (v0.2), and so do the cameras (`duo-camera`, v0.3).
2. **It designs, not just compiles.** Eight named layout patterns, state that survives fold and unfold, and two people on one screen, each with SwiftUI code. v0.2 adds design tokens, guidance for each pose, fold transitions, thumb reach and accessibility on both displays.
3. **It builds whole apps.** A recipe creates a project that builds and runs on the iPhone Duo simulator. Seven are ready: a two-player game, a finance dashboard, a media player, a reader, a shop, a learning app for young children and notes with on-device AI summaries. One more is planned.
4. **It checks its own work.** `duo-lint` finds code Apple warns against. `/duo-audit` adds a 15-point design checklist on screenshots from the simulator. `/duo-poses` (v0.2) screenshots your app closed, open, in book pose and in tabletop, and `/duo-review` hands those frames to a design review agent. `/duo-ship` checks the App Store rules for Duo before you submit, with a pose test agent and screenshots of both displays.
<div align="center">
<img src="docs/assets/how-it-works.svg" alt="You ask Claude Code, Duology guides the code, Xcode 27.1 builds it for the iPhone Duo simulator, duo-lint, the 15-point design review and screenshots of four poses (v0.2) check it, and `/duo-ship` (v0.4) runs the App Store checklist before you ship" width="100%" />
</div>
## Quick start
<details open>
<summary><strong>Claude Code</strong> · plugin marketplace</summary>
**You need:** a Mac with Apple silicon, [Xcode 27.1](https://developer.apple.com/news/releases/) (27A9275 or later) and Claude Code.
```bash
/plugin marketplace add Kimeur/duology
/plugin install duology@duology
```
Add the other plugins when you need them:
```bash
/plugin install duology-design@duology
/plugin install duology-recipes@duology
/plugin install duology-ship@duology
/plugin install duology-features@duology
```
`duology-recipes` and `duology-ship` need `duology`, which gives them `/duo-doctor`. `duology-design` and `duology-features` install on their own, but their skills point to `duology`'s skills (`duo-layout`, `duo-continuity`, `duo-scenes`), so install `duology` first. `duology-features` adds the iOS 27 features: Foundation Models, App Intents, the camera, media, reading, games, the iOS 27 SwiftUI changes, and widgets, Live Activities and Controls.
Restart Claude Code, then check your setup:
```
/duo-doctor
```
It checks macOS, Xcode 27.1, the iOS 27.1 simulator runtime, an iPhone Duo simulator, Xcode's agent bridge (`xcrun mcpbridge`) and Python for `duo-lint`. It tells you how to fix anything that fails, and it changes nothing on its own.
</details>
<details>
<summary><strong>Cursor, Codex, Copilot, Gemini CLI and others</strong> · skills only</summary>
```bash
npx skills add Kimeur/duology
```
The CLI finds your agent and puts the skills where it looks. You get every skill. Slash commands and the lint hook are Claude Code features, so on other agents ask for them in plain words ("run the Duo audit"). [AGENTS.md](AGENTS.md) lists the script behind each command.
One skill only:
```bash
npx skills add Kimeur/duology --skill duo-layout
```
Each skill works on its own: links that point outside its folder go to this repo on GitHub.
</details>
<details>
<summary><strong>Manual</strong></summary>
Each skill is a folder with a `SKILL.md`. Copy the ones you want into `.claude/skills/` (project) or `~/.claude/skills/` (everyone on this Mac).
</details>
### Ask Claude
```text
Make my app work well on iPhone Duo. Start with an audit, fix what it finds,
then run it on the Duo simulator.
```
```text
/duo-new recipe-two-player-game TapDuel
A reaction game: each player taps their own targets, first to ten wins.
```
```text
Review these Figma frames for iPhone Duo and tell me what breaks when the phone is half folded.
```
## What's inside
**34 skills in 5 plugins, 6 commands and 2 agents.** v0.4 added `duo-migrate`, `duo-app-store`, `recipe-kids-learning`, `/duo-ship` and the `duo-pose-tester` agent; `recipe-notes-ai` is new on `main` since. The full pack plans 36 skills in 5 plugins, 6 commands and 2 agents. Rows marked *planned* aren't built yet; the [roadmap](ROADMAP.md) says when they land. Claude loads a skill only when the task needs it, so the pack costs almost nothing while it sits unused.
<details open>
<summary><strong>duology</strong> · foundation: setup, layout, continuity, scenes</summary>
| Skill | Status | Use it when |
|---|---|---|
| `duo-start` | v0.1 | You're not sure where to begin. Works out SwiftUI or UIKit, new or existing app, and picks the right skills. |
| `duo-setup` | v0.1 | Setting up Xcode 27.1 next to an older Xcode, Device Hub, Xcode's agent connection, Swift 6 project settings. |
| `duo-layout` | v0.1 | Content lands in the fold. Size classes, uneven safe areas, reserved regions, `ArrangementView` and when to use your own split instead. |
| `duo-navigation` | v0.1 | Toolbars and tab bars. Vertical bars, tabs that become a sidebar, `NavigationSplitView`, sheets, overflow. |
| `duo-continuity` | v0.1 | Something resets when you fold. Scroll, playback, typed text, selection and navigation survive fold, unfold, rotate and resize. |
| `duo-scenes` | v0.2 | Several windows, Split View, and showing something on the outer display while the inner one is in use. |
</details>
<details>
<summary><strong>duology-design</strong> · design and interaction</summary>
| Skill | Status | Use it when |
|---|---|---|
| `duo-design-system` | v0.2 | Setting up spacing, grids (even column counts), type for both displays, Liquid Glass, corners, colour and contrast, touch targets. |
| `duo-patterns` | v0.1 | Choosing a layout. List-detail, supporting pane, two-page, dual view, extended canvas, feed reflow, tabs to sidebar, displacement. |
| `duo-postures` | v0.2 | Designing for closed, open, book, tabletop, standing and flipped. The hinge as an effect, used sparingly. |
| `duo-transitions` | v0.2 | The move from closed to open should feel like one app, not a reload. |
| `duo-ergonomics` | v0.2 | Two-handed grip, thumb reach, controls on the side edge. |
| `duo-shared-screen` | v0.1 | Two people use one phone: games, teaching, showing something to a customer. |
| `duo-accessibility` | v0.2 | VoiceOver order across panes, Dynamic Type on both displays, Reduce Motion, hardware keyboard. |
| `duo-design-review` | v0.1 | Reviewing screenshots or Figma frames against the 15-point Duo checklist. |
</details>
<details>
<summary><strong>duology-features</strong> · iOS 27 features on two displays</summary>
| Skill | Status | Use it when |
|---|---|---|
| `duo-intelligence` | v0.3 | Adding Foundation Models: an AI pane when open, a short summary when closed. |
| `duo-app-intents` | v0.3 | Siri, app actions and onscreen awareness with App Intents. |
| `duo-camera` | v0.3 | Capture apps. Each camera by the way it faces, the virtual front camera, a preview on the outer display. |
| `duo-media` | v0.3 | Video and audio. Tabletop player, Picture in Picture, "up next". |
| `duo-reading` | v0.3 | Books and documents. Two pages in book pose, notes beside the text. |
| `duo-games` | v0.3 | Games. Fill the screen in every pose, keep touch controls off the fold. |
| `duo-swiftui-27` | v0.3 | The iOS 27 SwiftUI changes that matter on Duo: reordering, swipe actions on any view, the `@State` macro, new toolbar APIs. |
| `duo-system-surfaces` | v0.3 | Widgets, Live Activities, StandBy and Controls on either display. |
</details>
<details>
<summary><strong>duology-recipes</strong> · app recipes</summary>
See [App recipes](#app-recipes).
</details>
<details>
<summary><strong>duology-ship</strong> · testing and App Store</summary>
| Skill | Status | Use it when |
|---|---|---|
| `duo-testing` | v0.1 | Writing tests that hold up on the Duo simulator: logic tested on the Mac, launch switches, UI tests that really reach SwiftUI gestures. |
| `duo-pose-matrix` | v0.2 | Screenshots of your app closed, open, in book pose and in tabletop, by pressing Device Hub's pose buttons (with your Accessibility permission) or with poses you set by hand. |
| `duo-lint` | v0.1 | Finding code Apple warns against before it ships. |
| `duo-migrate` | v0.4 | Bringing an app that ships today over: what its SDK shows on Duo, the scene life cycle, the patterns to fix, in order. |
| `duo-app-store` | v0.4 | App Store screenshots of both displays at the exact Duo sizes, App Review notes, the privacy manifest and the April 2027 rules. |
| `duo-performance` | planned (v1.0) | Resizing smoothly at 120 Hz when the phone opens. |
</details>
### Commands and agents
| Command | Status | What it does |
|---|---|---|
| `/duo-doctor` | v0.1 | Checks the Mac: Xcode 27.1, the iOS 27.1 runtime, an iPhone Duo simulator, Xcode's agent bridge and Python. |
| `/duo-new <recipe> <AppName>` | v0.1 | Creates a new app from a recipe, tests its rules on the Mac, builds it and runs it on the Duo simulator. |
| `/duo-audit` | v0.1 | Runs `duo-lint` and the 15-point checklist on your app and lists what to fix, most serious first. |
| `/duo-poses` | v0.2 | Runs your app closed, open, in book pose and in tabletop, saves a screenshot of each, and puts the simulator back. |
| `/duo-review` | v0.2 | Design critique of screenshots or Figma frames by the `duo-design-reviewer` agent. Reads only. |
| `/duo-ship` | v0.4 | App Store checklist for Duo: the April 2027 build rules, duo-lint, every pose, screenshots of both displays, the privacy manifest and App Review notes. Never uploads. |
| Agent | Status | What it does |
|---|---|---|
| `duo-design-reviewer` | v0.2 | Reviews a screen the way a Duo design lead would, with the rule behind each comment. |
| `duo-pose-tester` | v0.4 | Reads a pose run (the app launched in every pose, and kept running while it folds) and reports each failure with its screenshot. Reads only. |
<details>
<summary><strong>duo-lint</strong> · example report</summary>
Real output on a four-file sample, [`tests/fixtures/sample`](plugins/duology-ship/skills/duo-lint/tests/fixtures/sample) in the skill, run from that folder:
```text
$ duo-lint Sources/
Sources/App/RootView.swift:7 DUO004 warning userInterfaceIdiom == .pad layout picked by device type; pick it by size class or space
Sources/Feed/FeedView.swift:8 DUO001 error UIScreen.main.bounds your window is not the screen on a two-display phone; size from the view or window
Sources/Player/Controls.swift:9 DUO007 warning frame(width: 390) fixed width of 320 pt or more; let the container size it
Sources/Settings/SettingsView.swift:6 DUO009 warning <= 667 GeometryReader size compared to a device size; use size class or ViewThatFits
4 findings · 1 error · 3 warnings (4 files checked)
```
Each line gives the place, the rule, the severity, the code and what's wrong. An `error` is an API the SDK already deprecates; a `warning` is a pattern that is almost always wrong on iPhone Duo. Add `-v` to print the fix and the Apple source under each finding. It has nine rules (`DUO001` to `DUO009`) and prints text, JSON or GitHub annotations.
With `duology-ship` installed, Claude Code runs it as `duo-lint`. If you installed the skill on its own, run `<skill-folder>/scripts/duo-lint .` from your app's folder. `<skill-folder>` is the folder that holds the skill's `SKILL.md`. Turn on the optional hook (`export DUOLOGY_LINT_HOOK=1` before you start Claude Code) and Claude sees these findings right after it edits a Swift file. The hook never blocks an edit.
</details>
## Layout patterns
<div align="center">
<br />
<picture>
<source media="(prefers-color-scheme: dark)" srcset="docs/assets/hero-dark.png" />
<source media="(prefers-color-scheme: light)" srcset="docs/assets/hero-light.png" />
<img src="docs/assets/hero-light.png" alt="The gallery app's two-page screen on the iPhone Duo simulator: one page on the closed 5.4-inch outer display, two facing pages on the open 7.6-inch inner display" width="100%" />
</picture>
<br />
<sub>Real screenshots of the <a href="samples/DuologyGallery">gallery app</a> on the iPhone Duo simulator (iOS 27.1), drawn at the same scale.</sub>
<br /><br />
</div>
Every pattern in `duo-patterns` comes with a SwiftUI recipe and a screen in the gallery app ([`samples/DuologyGallery`](samples/DuologyGallery)).
| Pattern | Closed | Open | Good for |
|---|---|---|---|
| List-detail | list, then detail | both side by side | mail, messages, settings |
| Supporting pane | main content, pane in a sheet | main content with a narrower pane | comments, tools, "up next" |
| Two-page | one page | two pages, one per side | books, documents, slides |
| Dual view | one view, toggle | the same data two ways | list and map, text and preview |
| Extended canvas | canvas | the canvas spans the fold, tools stay clear of it | maps, drawing, big tables |
| Feed reflow | 1 or 2 columns | an even number of columns | photos, shops, news |
| Tabs to sidebar | tab bar on the side | sidebar | apps with many sections |
| Displacement | n/a | controls move off the fold, scrolling content stays put | any screen with controls near the middle |
The gallery app on the iPhone Duo simulator (iOS 27.1): closed on the outer display, open on the inner display. The [gallery README](samples/DuologyGallery/README.md#screenshots) also shows each screen in book and tabletop poses.
| Pattern | Closed | Open |
|---|---|---|
| List-detail | <img src="docs/assets/gallery/listDetail-closed.png" width="100" alt="Inbox list on the closed phone, with Close and filter buttons in the vertical bar" /> | <img src="docs/assets/gallery/listDetail-open.png" width="206" alt="Open: inbox list on the left, a message on the right, message actions in the vertical bar" /> |
| Supporting pane | <img src="docs/assets/gallery/supportingPane-closed.png" width="100" alt="Article on the closed phone, with Discussion and Share in the vertical bar" /> | <img src="docs/assets/gallery/supportingPane-open.png" width="206" alt="Open: the article with the discussion pane beside it" /> |
| Two-page | <img src="docs/assets/gallery/twoPage-closed.png" width="100" alt="Title page of the book on the closed phone, with page buttons at the bottom of the vertical bar" /> | <img src="docs/assets/gallery/twoPage-open.png" width="206" alt="Open: the title page and January as facing pages, the gap on the fold line" /> |
| Dual view | <img src="docs/assets/gallery/dualView-closed.png" width="100" alt="Places list on the closed phone with the List and Map switch" /> | <img src="docs/assets/gallery/dualView-open.png" width="206" alt="Open: the list of places on the left, the map of Lisbon on the right" /> |
| Extended canvas | <img src="docs/assets/gallery/extendedCanvas-closed.png" width="100" alt="Trail map on the closed phone with the tool palette at the bottom" /> | <img src="docs/assets/gallery/extendedCanvas-open.png" width="206" alt="Open: the trail map across the whole display, the palette bottom centre" /> |
| Feed reflow | <img src="docs/assets/gallery/feedReflow-closed.png" width="100" alt="Shop grid in two columns on the closed phone" /> | <img src="docs/assets/gallery/feedReflow-open.png" width="206" alt="Open: the shop grid in four columns" /> |
| Tabs to sidebar | <img src="docs/assets/gallery/tabsToSidebar-closed.png" width="100" alt="Listen Now on the closed phone with eight tabs in a vertical tab bar" /> | <img src="docs/assets/gallery/tabsToSidebar-open.png" width="206" alt="Open: a sidebar with a Library section next to Listen Now" /> |
| Displacement | <img src="docs/assets/gallery/displacement-closed.png" width="100" alt="Voice memo list on the closed phone with the record controls at the bottom" /> | <img src="docs/assets/gallery/displacement-open.png" width="206" alt="Open: voice memos with the record group bottom centre" /> |
v0.2 adds three screens, one for each of `duo-postures`, `duo-transitions` and `duo-design-system`. The last column shows the pose each one is about.
| Screen | Closed | Open | Folded |
|---|---|---|---|
| Tabletop player | <img src="docs/assets/gallery/tabletopPlayer-closed.png" width="100" alt="Closed: the kelp forest film above the player controls, with a subtitle" /> | <img src="docs/assets/gallery/tabletopPlayer-open.png" width="206" alt="Open: the film across the display, the controls floating over its bottom edge" /> | <img src="docs/assets/gallery/tabletopPlayer-tabletop.png" width="144" alt="Tabletop: the film above the fold, the same controls below it" /> |
| Fold transition | <img src="docs/assets/gallery/foldTransition-closed.png" width="100" alt="Closed: the rock-pooling guide at The middle shore, one paragraph highlighted and the next selected, reading tools at the bottom" /> | <img src="docs/assets/gallery/foldTransition-open.png" width="206" alt="Open: contents on the left of the fold, the same section and selection on the right" /> | <img src="docs/assets/gallery/foldTransition-book.png" width="206" alt="Book pose: the same split as open; nothing moved" /> |
| Design tokens | <img src="docs/assets/gallery/designTokens-closed.png" width="100" alt="Closed: the energy dashboard on a four-column grid with the margin and touch target overlays" /> | <img src="docs/assets/gallery/designTokens-open.png" width="206" alt="Open: eight columns, four on each side, with a 16 pt gutter on the dashed fold line" /> | <img src="docs/assets/gallery/designTokens-book.png" width="206" alt="Book pose: the fold as the middle gutter, four columns on each side" /> |
## App recipes
`/duo-new <recipe> <AppName>` creates the project, tests its rules on the Mac, builds it and opens it on the iPhone Duo simulator. 7 recipes are ready; the last one is planned.
| Recipe | Status | What you get |
|---|---|---|
| `recipe-two-player-game` | v0.1 | Each player gets half the screen in every pose, with the game logic tested on the Mac. |
| `recipe-finance-dashboard` | v0.3 | Balance when closed; balance, charts and transactions when open. |
| `recipe-media-player` | v0.3 | Player that moves to tabletop on its own, with "up next" and Picture in Picture. |
| `recipe-reader` | v0.3 | Two pages in book pose, and it remembers where you were. |
| `recipe-shop` | v0.3 | Product shelf beside product details, with a two-pane paywall. |
| `recipe-notes-ai` | next (on `main`) | Notes with on-device AI summaries: one line closed, a pane beside the note open, below the fold in tabletop, and a summary without AI when the model can't run. |
| `recipe-camera-studio` | planned (v1.0) | The person you film sees themselves on the outer display. |
| `recipe-kids-learning` | v0.4 | Counting and first letters read aloud, big answers below the fold in tabletop, a parental gate, a privacy manifest and nothing tracked. |
<p align="center"><img src="docs/assets/recipes/recipe-finance-dashboard-closed.png" alt="The finance dashboard recipe, closed pose, on the iPhone Duo simulator" width="48%" /> <img src="docs/assets/recipes/recipe-finance-dashboard-open.png" alt="The finance dashboard recipe, open pose, on the iPhone Duo simulator" width="48%" /><br /><sub>The finance dashboard recipe on the iPhone Duo simulator</sub></p>
<p align="center"><img src="docs/assets/recipes/recipe-media-player-closed.png" alt="The media player recipe, closed pose, on the iPhone Duo simulator" width="48%" /> <img src="docs/assets/recipes/recipe-media-player-tabletop.png" alt="The media player recipe, tabletop pose, on the iPhone Duo simulator" width="48%" /><br /><sub>The media player recipe on the iPhone Duo simulator</sub></p>
<p align="center"><img src="docs/assets/recipes/recipe-reader-book.png" alt="The reader recipe, book pose, on the iPhone Duo simulator" width="48%" /> <img src="docs/assets/recipes/recipe-reader-tabletop.png" alt="The reader recipe, tabletop pose, on the iPhone Duo simulator" width="48%" /><br /><sub>The reader recipe on the iPhone Duo simulator</sub></p>
<p align="center"><img src="docs/assets/recipes/recipe-shop-closed.png" alt="The shop recipe, closed pose, on the iPhone Duo simulator" width="48%" /> <img src="docs/assets/recipes/recipe-shop-open.png" alt="The shop recipe, open pose, on the iPhone Duo simulator" width="48%" /><br /><sub>The shop recipe on the iPhone Duo simulator</sub></p>
<p align="center"><img src="docs/assets/recipes/recipe-kids-learning-closed.png" alt="The kids learning recipe, closed pose, on the iPhone Duo simulator" width="32%" /> <img src="docs/assets/recipes/recipe-kids-learning-tabletop.png" alt="The kids learning recipe, tabletop pose, on the iPhone Duo simulator" width="32%" /><br /><sub>The kids learning recipe on the iPhone Duo simulator</sub></p>
<p align="center"><img src="docs/assets/recipes/recipe-notes-ai-closed.png" alt="The notes recipe, closed pose, on the iPhone Duo simulator: the note with a one-line summary bar" width="27%" /> <img src="docs/assets/recipes/recipe-notes-ai-book.png" alt="The notes recipe, book pose, on the iPhone Duo simulator: the note on the left page, the summary on the right" width="55%" /><br /><sub>The notes recipe on the iPhone Duo simulator (a summary without AI: the model doesn't run on the simulator)</sub></p>
## Proof, not promises
Every skill has test tasks in [`evals/`](evals), 45 so far (44 ready to run). Each task runs with Claude Code twice, with and without Duology, in a fresh copy of the same sample project. A run passes when the app builds for the iPhone Duo simulator, `duo-lint` finds nothing, every check in the task passes and every checklist rule it covers passes.
No results yet. The first published runs are planned before v1.0, and we'll publish them here whatever they show.
| Task | Without Duology | With Duology |
|---|---|---|
| Make an existing list app work on Duo | *pending* | *pending* |
| Keep video playing through fold and unfold | *pending* | *pending* |
| Build a two-player game on one phone | *pending* | *pending* |
| Tabletop layout for a video call | *pending* | *pending* |
How the runs work and how to rerun them: [`evals/README.md`](evals/README.md).
### Verified on
| | Status |
|---|---|
| Xcode 27.1 (27A9275) | Checked |
| iPhone Duo simulator, iOS 27.1 | Checked |
| iPhone Duo device | Planned before v1.0 |
| iOS 27.2 beta | Not tracked until release |
Each `SKILL.md` repeats this in its front matter, so you can see how far every rule has been tested.
## FAQ
<details>
<summary><strong>How is this different from other iPhone Duo skill repos?</strong></summary>
Other repos explain the Duo APIs well, and [mirzaaghazadeh/iphone-duo-skills](https://github.com/mirzaaghazadeh/iphone-duo-skills) also covers Flutter, React Native and Capacitor. Duology aims to go from design to the App Store for native SwiftUI and UIKit apps. v0.1 has layout patterns, a recipe, a linter, an audit command and a test harness. v0.2 adds design skills, a scenes skill, the pose screenshots (`/duo-poses`) and a design review agent. v0.3 adds eight iOS 27 feature skills and four more recipes. The App Store skill and published test results come later.
</details>
<details>
<summary><strong>Xcode 27 already ships agent skills. Why add more?</strong></summary>
Apple's skills (export them with `xcrun agent skills export`) cover SwiftUI in general and making apps resizable. Duology points to them and doesn't copy them. It adds what they don't cover: design for each pose, two-person use, recipes and verification.
</details>
<details>
<summary><strong>Do I need an iPhone Duo?</strong></summary>
No. Everything runs on the iPhone Duo simulator in Xcode 27.1. A few things only show on real hardware (how the hinge feels, camera handoff, 120 Hz transitions); those skills say so.
</details>
<details>
<summary><strong>Does it work with UIKit?</strong></summary>
Yes. `duo-layout`, `duo-navigation`, `duo-continuity` and `duo-shared-screen` give SwiftUI and UIKit versions, and so do the v0.2 skills (`duo-scenes`, `duo-design-system`, `duo-postures`, `duo-transitions`, `duo-ergonomics`, `duo-accessibility`). `duo-patterns` builds in SwiftUI and maps each pattern to its UIKit counterpart. The recipes are SwiftUI apps.
</details>
<details>
<summary><strong>Does Duology send any data anywhere?</strong></summary>
No. Skills are text files, and `duo-lint`, `duo-doctor` and the `duo-pose-matrix` tools run on your Mac.
</details>
## Documentation
- [Roadmap](ROADMAP.md): what's planned and when.
- [Changelog](CHANGELOG.md): what changed in each release.
- [AGENTS.md](AGENTS.md): using Duology from Codex, Cursor, Copilot, Gemini CLI and other agents.
- [Gallery app](samples/DuologyGallery/README.md): how to run it and what each screen shows.
- [Evals](evals/README.md): how the test runs work.
- [Device facts](reference/device-facts.md): displays, cameras, poses, size classes.
- [API index](reference/api-index.md): every Duo API with its Apple doc link.
- [Sources](reference/sources.md): the Apple pages and talks behind each rule.
- [Contributing](CONTRIBUTING.md): how to add a skill, a pattern or a recipe.
- [Security](SECURITY.md): how to report a security problem.
## Star history
<a href="https://www.star-history.com/?repos=Kimeur%2Fduology&type=date">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/chart?repos=Kimeur/duology&type=date&theme=dark&legend=top-left" />
<source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/chart?repos=Kimeur/duology&type=date" />
<img alt="Duology GitHub star history" src="https://api.star-history.com/chart?repos=Kimeur/duology&type=date" />
</picture>
</a>
## Contributing
Pull requests are welcome, especially new patterns, recipes and test tasks. Each change needs:
- a link to the Apple doc or talk behind any API claim;
- a test task in `evals/` for any new skill;
- a `verified:` line saying where you tested it.
Read [CONTRIBUTING.md](CONTRIBUTING.md) before you start. Found a wrong API claim? [Open an issue](https://github.com/Kimeur/duology/issues/new?template=api-correction.yml) with the Apple link.
## Acknowledgements
Built on Apple's iPhone Duo Tech Talks and Human Interface Guidelines, and on design ideas from Microsoft's Surface Duo patterns, Android's adaptive layouts and Samsung's Flex mode. Thanks to the Swift agent-skills community: [twostraws](https://github.com/twostraws/Swift-Agent-Skills), [AvdLee](https://github.com/AvdLee/SwiftUI-Agent-Skill), [Dimillian](https://github.com/Dimillian/Skills) and [mirzaaghazadeh](https://github.com/mirzaaghazadeh/iphone-duo-skills).
## License
[MIT](LICENSE). Apple documentation is linked, never copied. Apple, iPhone and Xcode are trademarks of Apple Inc.
