Xcode Agent Skills: How to Export and Use Them in Xcode 27

Coding agents are good at writing Swift, but they learn APIs from whatever they were trained on, and that is usually a release or two behind. Xcode agent skills close that gap. Xcode 27 ships skills written by Apple that tell an agent how to use current best practices and the newest APIs, and one command exports them for agents that run outside Xcode. This guide covers what the skills are, how to export them, why a copy from before Xcode 27.1 is out of date, and how the App Resizability skill helps you get an app ready for iPhone Duo.

Everything here comes from Apple's WWDC26 sessions, the iPhone Duo Tech Talks, Apple's documentation and release notes, and developer reports, which we credit where they're the only source. The AppleDuo team hasn't run these skills on a shipping app. Xcode 27.x is new, so names and behavior can change between releases.

What are Xcode 27 agent skills?

A skill is a packet of expertise an agent can load when a task calls for it. Apple's documentation for extending and customizing agents describes it as built-in expertise "that can guide agents to use the best APIs and workflows for high-level tasks." Inside Xcode you rarely have to ask for one: Xcode uses the right skill based on the prompt you type.

You can also call a skill directly. The Xcode 27 release notes say skills "are invokable as slash commands with completion support." Type / in the coding assistant's message field to see every skill your copy of Xcode has. The same release added plug-ins that bundle skills, MCP servers and agent configurations, so the list can grow beyond Apple's own.

In the WWDC26 session What's new in SwiftUI, Apple says the new skills are there to help you adopt features from the 2027 releases, "and improve your app's performance and code correctness." That is the core idea: the agent gets Apple's current guidance instead of relying on older training data.

Which agent skills ship with Xcode 27?

Apple hasn't published a single list. These are the skills named in Apple's own sessions and release notes, with the version that introduced each one.

Xcode also includes workflow skills, such as /plan for plan mode, and the release notes mention Apple-built specialists for localization, UIKit resizing and accessibility. Your exported folder is the most reliable list for the Xcode version you have installed.

How do I export Xcode agent skills with xcrun?

Apple gives the command in two WWDC26 sessions. In Modernize your UIKit app, the presenter says that to use skills in other tools, "you can export the ones Xcode uses" with xcrun agent skills export, which creates Markdown files you can import into your workflows.

@sarunw shared the version with an output folder:

xcrun agent skills export --output-dir ~/Downloads/xcode-skills

xcrun runs the tool from your active developer directory, so make sure that points at Xcode 27 or later first. Reda Lemeden's write-up notes that you can switch back afterward, because the exported files stay where you put them. The xcode-select commands below are standard macOS tools; adjust the path to wherever your Xcode lives.

# Check which Xcode xcrun will use
xcode-select -p

# Point it at Xcode 27.1 or later, then export
sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
xcrun agent skills export --output-dir ~/Downloads/xcode-skills
ls ~/Downloads/xcode-skills

According to Lemeden, running the command without --output-dir exports into the current directory, with one folder per skill. Apple hasn't documented other flags, so we haven't listed any.

Can I use Xcode's agent skills with Claude Code or other agents?

Yes, that is the point of the export. Apple's iPhone Duo preparation page says it plainly: "If you use a different coding agent, export the skill." What Apple doesn't document is how each agent should load the files. That depends on the agent.

Lemeden reports exporting straight into a Claude Code skills folder, and says the files work with any harness that supports the skills format, naming Claude Code and OpenCode:

xcrun agent skills export --output-dir ~/.claude/skills

A per-project folder works too if you'd rather keep the skills with one repository. Whichever agent you use, check its own documentation for where skills live and how they're triggered.

Two practical notes. First, the skills are Apple's content. Export them from your own copy of Xcode instead of pulling a copy someone else posted, so you get the version that matches your SDK. Second, an agent outside Xcode can only check its work if it can build and run your app. The Xcode 27 release notes describe a preview of an Xcode MCP server that runs without an open workspace, turned on with sudo xcrun mcp-server enable. It's an early preview, so expect rough edges.

If agents will be editing your project file as well as your code, Xcode 27.2's new JSON project format is easier for them to read and merge. We cover it in the Xcode 27 .xcproj format.

Why should I re-export skills after Xcode 27.1?

Skills are versioned with Xcode, and Xcode 27.1 changed one that matters for iPhone Duo. In the Tech Talk Prepare your app for iPhone Duo, Apple says the app modernization skill from "Modernize your UIKit app" has a new name in Xcode 27.1: "App Resizability. It now supports SwiftUI and iPhone Duo."

@sarunw spelled out what that means for exported copies: if you exported before Xcode 27.1, export again, because uikit-app-modernization is now app-resizability. A folder exported from Xcode 27.0 keeps the old skill, which knows nothing about iPhone Duo or SwiftUI.

When you re-export, delete the old folder first, or export to a new path, so your agent doesn't load both versions. Do the same after each Xcode update, since Apple can revise any skill between releases.

How do I use the App Resizability skill for iPhone Duo?

Inside Xcode, Apple's iPhone Duo preparation page says to ask the coding assistant to "get my app ready for iPhone Duo." The skill scans your project, and for each issue it finds, it explains the problem and suggests a fix. With an exported copy, give your agent the same request and point it at the skill.

The WWDC26 UIKit session lists what the skill does on its own: it converts main-screen calls to trait collection or scene bounds checks, replaces interface orientation checks with size class checks, and can move an app to the scene life cycle. For bigger jobs it asks clarifying questions, and for work too large for one session it leaves comments so you can track what's left.

A typical change looks like this. Both lines use standard UIKit API, and Apple's preparation page calls out this exact replacement:

// Before: sized from the main screen
let window = UIWindow(frame: UIScreen.main.bounds)

// After: created from the scene, so it follows the scene's size
let window = UIWindow(windowScene: windowScene)

Apple is clear that the skill "finds most issues, but not all of them." Use its pass as a first sweep, then review the patterns Apple asks you to fix by hand:

• Stop sizing from the main screen. Replace UIScreen.main.bounds with view.bounds or window.bounds, and use GeometryReader or onGeometryChange in SwiftUI.
• Don't use orientation for layout. Remove layout logic that reads UIDevice.current.orientation, statusBarOrientation or interfaceOrientation.
• Don't treat idiom or size class as a device. On iPhone Duo an iPhone app can get any combination of size classes, so regular width no longer means iPad. Our iPhone Duo size classes guide covers the details.
• Check full-bleed media. Fill-mode hero images can lose content on the wider inner display.

Then build with the iOS 27.1 SDK, which extends apps to the full display with vertical bars, and test. Our prepare your app for iPhone Duo checklist puts these steps in order.

What changed in Device Hub in Xcode 27.2?

Agent changes still need testing, and Device Hub is where you do it. With Xcode 27.1 you pick the iPhone Duo simulator and use the controls at the bottom of the screen to open, close, rotate or fold the device. The Xcode 27.2 release notes add a list of improvements, including several that @sarunw highlighted:

• StandBy support in iPhone Duo
• Slow Motion Animation, Simulate Shake, Simulate Fall and Simulate Memory Pressure (simulators only)
• Touch events through Sidecar, so pinch and rotate work from an iPad screen
• An option to hide device bezels, plus screenshot and keyboard improvements

Slow motion helps you watch a layout change while the device folds, and memory pressure shows whether your state survives a resize under load. Apple's 27.2 notes also list known issues: VoiceOver and the Accessibility Inspector can't convey iPhone Duo screen content inside Device Hub, and screenshots may be black for a few minutes after booting the device.

Key takeaways

• Xcode 27 agent skills are Apple-written guidance for coding agents, applied automatically or through slash commands.
• Export them with xcrun agent skills export plus --output-dir and a folder to use them with another agent; Apple says the export produces Markdown files.
• Re-export after Xcode 27.1: uikit-app-modernization became app-resizability, with SwiftUI and iPhone Duo support.
• Ask for "get my app ready for iPhone Duo," then review what the skill misses, since Apple says it doesn't catch everything.
• Test the result in Device Hub, which gains slow motion, memory pressure, shake and fall simulations in Xcode 27.2.

Next, work through the iPhone Duo preparation checklist, and see apps that already make the most of the hinge in Built for the fold.