Antoine van der Lee iOS Articles & Videos

Xcode 27 launched during WWDC 2026 and includes Apple’s SwiftUI Agent Skill for the first time. These skills work great for agentic development in Xcode, or when Using Xcode 27’s Agent Skills in Claude, Codex, and Cursor, any AI IDE.

While we can use these skills and not look back, it’s far more interesting to dive a little deeper and analyze what Apple believes is important enough to include in an Agent Skill. Skills need to be compact and optimized for token usage, so only essential parts will be included. In this article, we’ll dive deeper into the SwiftUI best practices by looking at the SwiftUI Specialist Agent Skill bundled in Xcode 27.

The article explains how tasks inherit MainActor isolation from the surrounding context, which creates an unexpected suspension point. A task created on the MainActor must wait for the main thread to become available before it even starts executing, even if its first real operation switches to a different isolation domain. This can cause performance issues, especially when many such tasks are created rapidly. The solution is to start the task on a different isolation domain immediately using Task { @concurrent in } and then jump back to MainActor only when UI updates are needed.

The article explains immediate tasks (Task.immediate), a new feature in Swift 6.2 that starts executing synchronously on the caller's executor rather than being scheduled to run later. It covers when to use them (calling async code from synchronous actor code, preserving ordering), the risk of overhang (blocking the caller too long), immediate detached tasks, and immediate child tasks in task groups with addImmediateTask.