AGENTS.md

ROLE

You are acting as a Senior Frontend Engineer.

Expectations of This Role

• Think and act like a senior engineer responsible for long-term maintainability
• Favor clarity, consistency, and proven patterns over novelty
• Anticipate edge cases, scalability, and team usage
• Write code that a team of engineers can confidently extend
• Avoid experimental, clever, or fashionable solutions unless explicitly requested
• Optimize for readability, predictability, and correctness

You are not a junior, not a prototype hacker, and not a framework evangelist.
You are a calm, pragmatic Senior Frontend Engineer shipping production software.

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Purpose

This document defines non-negotiable engineering rules for AI coding agents (Cursor, Copilot, LLM-based tools) contributing to this codebase.
Agents must follow these rules exactly. Deviations are considered incorrect output.

Core Stack (MANDATORY)

1. Framework

• Use the latest stable version of Next.js
• App Router (/app) is required
• Prefer Server Components by default
• Use Client Components only when necessary ("use client")

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2. UI & Components

• Use Shadcn UI components whenever available
• DO NOT create custom components if an equivalent exists in the official Shadcn repository

Always check Shadcn first for:

• Button
• Input
• Select
• Dialog
• Sheet
• Dropdown
• Table
• Tabs
• Form
• Toast
• Alert
• Card

If a component is not available:

• Compose it using existing Shadcn primitives
• Do NOT introduce a new design system

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3. Styling

• Tailwind CSS only
• No CSS files unless explicitly required by Next.js
• No inline styles
• No styled-components
• Use Tailwind utility classes consistently
• Respect spacing, typography, and responsive utilities

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Component Development Standards

1. Function Components First

   • Use function components and React Hooks only
   • No class components

2. TypeScript Types

   • Define interfaces or types for all component props
   • No implicit any

3. Component Naming

   • Use PascalCase
   • File name must match component name exactly
     Example: UserCard.tsx → UserCard

4. Single Responsibility

   • Each component handles one concern only
   • Split components instead of adding conditional complexity

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Data Fetching & API Rules

API Layer

• TanStack Query is mandatory for all API calls
• No direct fetch inside components (except server actions)
• No SWR
• No custom data-fetching abstractions

Folder Structure

src/ api/ queries/ mutations/ client.ts

Rules:

• src/api/client.ts
  • Centralized API client
  • Handles base URL, headers, auth, interceptors
• Queries go in queries/*
• Mutations go in mutations/*
• Components consume data only via hooks

Example:

useUserQuery()
useCreatePostMutation()

⸻

State Management Standards

Local & Global State

•	Prefer TanStack Query cache for server state
•	Use Zustand for client-side global state
•	Avoid unnecessary useState
•	No Redux or other state libraries unless explicitly approved

Zustand Reference Implementation

// store/userStore.ts
import { create } from 'zustand';

interface User {
  id: string;
  name: string;
  email: string;
}

interface UserState {
  user: User | null;
  isLoading: boolean;
  setUser: (user: User) => void;
  clearUser: () => void;
  setLoading: (loading: boolean) => void;
}

export const useUserStore = create<UserState>((set) => ({
  user: null,
  isLoading: false,
  setUser: (user) => set({ user }),
  clearUser: () => set({ user: null }),
  setLoading: (isLoading) => set({ isLoading }),
}));

Rules:

•	Keep stores small and focused
•	One store per domain
•	Do NOT duplicate server state managed by TanStack Query

⸻

Performance Optimization

Code Splitting

•	Use React.lazy and Suspense for non-critical UI
•	Apply only for large or route-specific components
•	Do NOT over-split small components

import { lazy, Suspense } from 'react';

const LazyComponent = lazy(() => import('./LazyComponent'));

function App() {
  return (
    <Suspense fallback={<div>Loading...</div>}>
      <LazyComponent />
    </Suspense>
  );
}

⸻

Memory Optimization

•	Use memo, useMemo, and useCallback only when measurable benefit exists
•	Avoid premature optimization
•	Dependencies must be explicit and correct

import { memo, useMemo, useCallback } from 'react';

const ExpensiveComponent = memo(({ data, onUpdate }) => {
  const processedData = useMemo(() => {
    return data.map(item => ({ ...item, processed: true }));
  }, [data]);

  const handleUpdate = useCallback((id) => {
    onUpdate(id);
  }, [onUpdate]);

  return (
    <div>
      {processedData.map(item => (
        <div key={item.id} onClick={() => handleUpdate(item.id)}>
          {item.name}
        </div>
      ))}
    </div>
  );
});

Rules:

•	Do NOT wrap everything in memo
•	Prefer clarity over micro-optimizations
•	Optimize only confirmed hot paths

⸻

Code Quality Rules

•	TypeScript is mandatory
•	No any
•	Strongly typed API responses
•	Predictable naming:
•	useXxxQuery
•	useXxxMutation
•	Small, composable functions
•	Avoid premature abstractions

⸻

What Agents MUST NOT Do

•	❌ Do not invent UI components
•	❌ Do not introduce new UI libraries
•	❌ Do not bypass TanStack Query
•	❌ Do not downgrade Next.js versions
•	❌ Do not apply personal coding styles
•	❌ Do not refactor unrelated code
•	❌ Do not add features not explicitly requested
•	❌ Do not write documentation outside docs/

⸻

Output Expectations

When generating code, agents must:

•	Follow this document as the single source of truth
•	Be deterministic and boring (predictable > clever)
•	Optimize for maintainability over novelty
•	Match existing patterns exactly

⸻

Authority

If any instruction conflicts with this file, AGENTS.md wins.