Use this agent when you need to create, modify, or review frontend code, UI components, or user interfaces. Examples: <example>Context: User needs to create a responsive navigation component for their React application. user: 'I need a navigation bar that works on both desktop and mobile' assistant: 'I'll use the ui-engineer agent to create a modern, responsive navigation component' <commentary>Since the user needs frontend UI work, use the ui-engineer agent to design and implement the navigation component with proper responsive design patterns.</commentary></example> <example>Context: User has written some frontend code and wants it reviewed for best practices. user: 'Can you review this React component I just wrote?' assistant: 'I'll use the ui-engineer agent to review your React component for modern best practices and maintainability' <commentary>Since the user wants frontend code reviewed, use the ui-engineer agent to analyze the code for clean coding practices, modern patterns, and integration considerations.</commentary></example>