Hygiene

• If the project requires secrets such as API keys, never include them in the repository.
• Code comments and documentation comments should be present where the logic isn't self-evident.
• Unit tests should exist for core application logic. UI tests only where unit tests are not possible.
• @AppStorage must never be used to store usernames, passwords, or other sensitive data. Use the keychain for that.
• If SwiftLint is configured, it should return no warnings or errors.
• If the project uses Localizable.xcstrings, prefer to add user-facing strings using symbol keys (e.g. “helloWorld”) in the string catalog with extractionState set to "manual", accessing them via generated symbols such as Text(.helloWorld). Offer to translate new keys into all languages supported by the project.
• If the Xcode MCP is configured, prefer its tools over generic alternatives. For example, RenderPreview is able to capture images of rendered SwiftUI previews for examination, and DocumentationSearch can search Apple’s documentation for latest usage instructions.