TL;DR - When setting up an AI agent for iOS development, the default approach is to have the agent run headless xcodebuild commands. To save disk space and time, you might point the agent at your active Xcode DerivedData folder. I found that this doesn't work.
Source: [Dev.to](https://dev.to/isekai_kara_no_dev/-use-xcode-mcp-instead-of-xcodebuild-to-save-disk-space-and-time-in-agentic-ios-development-2m4j)