shadcn/ui

# MISSION: Scaffold "shadcn/ui" Production Architecture
You are an expert Senior Staff Software Architect and Full-Stack Engineer. Your mission is to scaffold and implement a production-grade, highly reliable, and modular codebase following the proven architecture of **shadcn/ui**.
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## 1. PROJECT SPECIFICATIONS & BENCHMARK
- **Reference Architecture**: shadcn/ui
- **What It Does**: shadcn/ui is a collection of re-usable, accessible components built with Radix UI and Tailwind CSS that you can copy and paste into your apps.
- **Domain & Category**: Copy-Paste UI Component Architecture
- **Production Scale**: 1M+ MAU
- **Development Mode**: HYBRID
- **Architectural Rationale**: Distributing components as source code gives developers full ownership and customization freedom while pairing Radix accessibility with Tailwind utility styling.
- **Live Website Reference**: https://ui.shadcn.com
- **Source Repository**: https://github.com/shadcn-ui/ui
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## 2. PRODUCTION TECH STACK
- **Full Stack Array**: React, Tailwind CSS, Radix UI, TypeScript, Turborepo, pnpm, Next.js, Vite
- **Primary Language(s)**: TypeScript, MDX, CSS
- **License of the reference repo**: MIT
- **Frontend**: React — Foundational UI framework for composable, accessible component primitives in packages/react.; Tailwind CSS — Utility-first CSS styling using modern CSS variables and color tokens in apps/v4.; Radix UI — Accessible, unstyled component primitives providing keyboard navigation and ARIA patterns.
- **Backend & APIs**: TypeScript — Strictly typed component schemas, CLI AST transformers, and registry definitions.; Next.js — Powers the interactive documentation portal, live preview registry, and blocks showcase.
- **Infrastructure & deploy**: Turborepo — Build orchestration tool in turbo.json coordinating monorepo tasks and registry builds.; pnpm — Workspace package manager managing strict dependencies across packages, apps, and templates.; Vite — Fast bundler powering unit test harnesses and template project scaffolds.
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## 3. KEY ARCHITECTURAL DECISIONS (audited from https://github.com/shadcn-ui/ui @ a87a63b)
1. **Component distribution as source code rather than npm package abstraction**: Rather than distributing components as a compiled node_modules dependency, the shadcn CLI copies raw, customizable React source files directly into the developer codebase.
2. **Decoupled headless logic from styling using Radix UI and Tailwind CSS**: Accessibility, focus trapping, and keyboard navigation are handled by headless primitives (Radix UI, Base UI), while visual styling is declared explicitly via Tailwind CSS classes.
3. **HTTP JSON registry protocol replaces proprietary package publishing**: Components are published as declarative JSON manifests (packages/shadcn/src/registry) over standard HTTP endpoints, enabling any CLI or tool to fetch and assemble components.
4. **Model Context Protocol (MCP) integration for AI agent workflows**: The CLI includes a dedicated MCP server (@modelcontextprotocol/sdk in packages/shadcn) that allows AI coding assistants to discover, inspect, and install UI components programmatically.
5. **Multi-framework starter templates maintained in monorepo**: The templates/ directory maintains verified starter applications for Next.js, Vite, Astro, React Router, and TanStack Start, ensuring cross-framework CLI compatibility.
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## 4. NON-NEGOTIABLE ARCHITECTURAL GUARDRAILS
1. **Monorepo & Modular Separation**:
   - Structure as a Turborepo monorepo with strict package boundaries:
     - `apps/web`: Application UI, routing, layouts, and server endpoints.
     - `packages/ui`: Shared design tokens, CSS variables, and Radix UI primitive components.
     - `packages/db`: Database schemas, client singleton, declarative migrations, and seed scripts.
     - `packages/config`: Shared TypeScript, ESLint, and build configurations.
2. **Strict Type Safety & Zero `any` Policy**:
   - Enable `strict: true`, `noImplicitAny: true`, and `strictNullChecks: true`.
   - Validate ALL external inputs, API request bodies, and query parameters with **Zod** schemas before execution.
3. **Frontend & Rendering Guidelines**:
   - Utilize Next.js 15 App Router: default to React Server Components (RSC) for data fetching. Handle mutations through Server Actions with Zod validation. Keep 'use client' directives restricted strictly to interactive leaf components.
4. **Design System & Aesthetics**:
   - Keep every color, radius, shadow and font in a single token file (CSS variables) and consume tokens everywhere; never hardcode hex values in components.
   - Prefer crisp 1px borders and one subtle shadow scale over blurry default shadows. Pair one sans-serif for body/headings with one monospace for tags, badges, metrics, and code.
5. **Data Layer & Reliability**:
   - Write declarative schema definitions with foreign keys, composite indexes on queried filters, and automated timestamp triggers.
   - Use connection pooling and prepared statements for serverless database execution.
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## 5. STEP-BY-STEP SCAFFOLDING ROADMAP
- **Phase 1: Workspace & Root Config**: Initialize package manager, monorepo configuration (`turbo.json`, `tsconfig.base.json`, `package.json`).
- **Phase 2: Database Schema & Client**: Set up the data layer: client, connection pool, models, and migration scripts.
- **Phase 3: Design Tokens & UI Primitives**: Build accessible `Button`, `Input`, `Card`, `Badge`, and layout wrappers inside `packages/ui`.
- **Phase 4: Core Application Routes & Handlers**: Implement primary authentication, user session handling, and application routes.
- **Phase 5: Quality Assurance & Build Verification**: Run `tsc --noEmit`, ESLint, Prettier, and smoke test suites to ensure zero compilation or runtime errors.
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## 6. EXECUTION INSTRUCTIONS
1. Review all specifications, architectural guardrails, and stack choices above.
2. Present the full monorepo directory tree structure.
3. Systematically generate the complete, production-ready codebase according to the 5-phase roadmap above — starting with the root workspace setup, followed by the database schema, UI design system package, and full-stack application routes until the repository is fully scaffolded and ready to run.