Xcode 26.3 integrates the Claude Agent SDK
Apple's Xcode 26.3 release candidate added a native Claude Agent SDK integration with subagents, background tasks, plugins, project-wide reasoning, and Apple-documentation search. Claude could also inspect Xcode Previews, iterate on SwiftUI output, and expose Xcode capabilities to Claude Code through MCP.
Why it matters: Apple developers gained an agent loop that can write code, inspect the rendered interface, and correct its own work without leaving Xcode.