Merge transformed its frontend development by adopting an opinionated design system, combining Tailwind CSS for styling and Material UI's unstyled components to improve code maintainability and accelerate feature shipping. This approach addressed the challenges of decision fatigue and inconsistent coding practices that arose from React's un-opinionated nature. By establishing clear guidelines, like using a single React component per file and extracting complex logic from JSX, Merge enhanced codebase navigation and reduced cognitive overhead. The implementation of atomic design principles allowed for scalable UI component construction, where foundational elements such as color tokens and typography were consistently applied across atoms and molecules. This systematic approach facilitated AI agents in writing production-ready frontend code by providing them with clear patterns, consistent conventions, and well-documented components. The success of this strategy highlights the potential of opinionated systems to enhance both human and AI productivity in software development, emphasizing the importance of clear guidelines and structured design for effective collaboration and innovation.