The Front-End Checklist is a comprehensive, open-source platform for front-end quality assurance, targeting both human developers and AI agents. It delivers a curated corpus of 386+ best-practice rules across 11 categories (HTML, CSS, JavaScript, Performance, Accessibility, SEO, Security, Images, Testing, Privacy, i18n) via a Next.js web application, a Model Context Protocol (MCP) server, and a standalone CLI. The architecture is a pnpm monorepo with shared packages for authentication (Better Auth + Prisma), design system (Radix UI), analytics (OpenPanel), state management (Zustand), search (FlexSearch), storage (IndexedDB), and validation. The MCP server exposes 11 tools (audit_url, review_code, search_rules, etc.) for AI-assisted code review and URL auditing, while the CLI provides offline audit capabilities. The web app offers rule browsing, user checklists with progress tracking, guides, and public profiles. The system is production-deployed on Vercel with PostgreSQL, Sentry error tracking, and Upstash rate limiting.