tabatago/AGENTS.md

AGENTS.md

This file contains optimizations and best practices for working with this TabataFit Expo project.

---

🚀 Command Optimizations

Use the following rtk commands for optimal performance:

Command	rtk Equivalent	Speedup	Tokens Before	Tokens After	Savings
ls / tree	rtk ls	10x	2,000	400	-80%
cat / read	rtk read	20x	40,000	12,000	-70%
grep / rg	rtk grep	8x	16,000	3,200	-80%
git status	rtk git status	10x	3,000	600	-80%
git diff	rtk git diff	5x	10,000	2,500	-75%
git log	rtk git log	5x	2,500	500	-80%
git add/commit/push	rtk git	8x	1,600	120	-92%
cargo test / npm test	rtk test	5x	25,000	2,500	-90%
ruff check	rtk lint	3x	3,000	600	-80%
pytest	rtk pytest	4x	8,000	800	-90%
go test	rtk gotest	3x	6,000	600	-90%
docker ps	rtk docker	-	-	-	-

Usage Examples

# Instead of: ls -la src/
rtk ls src/

# Instead of: cat package.json
rtk read package.json

# Instead of: grep -r "useEffect" src/
rtk grep "useEffect" src/

# Instead of: git status
rtk git status

# Instead of: npm test
rtk test

# Instead of: ruff check .
rtk lint

---

📱 Expo Best Practices

Development Workflow

CRITICAL: Always try Expo Go first before creating custom builds.

1. Start with Expo Go: Run npx expo start and scan the QR code with Expo Go
2. Check if features work: Test your app thoroughly in Expo Go
3. Only create custom builds when required

When Custom Builds Are Required

Use npx expo run:ios/android or eas build ONLY when using:

• Local Expo modules (custom native code in modules/)
• Apple targets (widgets, app clips, extensions via @bacons/apple-targets)
• Third-party native modules not included in Expo Go
• Custom native configuration that can't be expressed in app.json

When Expo Go Works

Expo Go supports a huge range of features out of the box:

• All expo-* packages (camera, location, notifications, etc.)
• Expo Router navigation
• Most UI libraries (reanimated, gesture handler, etc.)
• Push notifications, deep links, and more

Common Commands

# Development
npx expo start              # Start development server
npx expo start --tunnel     # If network issues
npx expo start --clear      # Clear cache
npx tsc --noEmit            # Type check
npx expo install <pkg>      # Install Expo-compatible packages

# Building
npx eas-cli@latest build --profile development     # Dev build
npx eas-cli@latest build -p ios --profile production --submit  # Build and submit iOS
npx testflight              # Quick TestFlight shortcut

# Development Client (when native code changes)
npx expo start --dev-client

Code Style Rules

File Naming

• Use kebab-case for file names (e.g., workout-card.tsx)
• Never use special characters in file names
• Always remove old route files when moving or restructuring navigation

Imports

• Use path aliases from tsconfig.json instead of relative imports
• Prefer aliases over relative imports for refactors
• Always use import statements at the top of the file

Library Preferences

• ✅ expo-audio not expo-av
• ✅ expo-video not expo-av
• ✅ expo-image with source="sf:name" for SF Symbols
• ✅ react-native-safe-area-context not react-native SafeAreaView
• ✅ process.env.EXPO_OS not Platform.OS
• ✅ React.use not React.useContext
• ❌ Never use modules removed from React Native: Picker, WebView, SafeAreaView, AsyncStorage
• ❌ Never use legacy expo-permissions
• ❌ Never use intrinsic elements like 'img' or 'div' unless in webview

Route Structure

app/
  _layout.tsx          # Root layout with tabs
  (tabs)/              # Group routes for tabs
    _layout.tsx        # Tabs layout
    index.tsx          # Home tab
    workouts.tsx       # Workouts tab
    activity.tsx       # Activity tab
    browse.tsx         # Browse tab
    profile.tsx        # Profile tab
  player/
    [id].tsx           # Workout player

Route Rules

• Routes belong in the app directory
• Never co-locate components, types, or utilities in the app directory
• Ensure the app always has a route that matches "/"
• Always use _layout.tsx files to define stacks

UI Guidelines

Responsiveness

• Always wrap root component in a scroll view for responsiveness
• Use <ScrollView contentInsetAdjustmentBehavior="automatic" /> instead of <SafeAreaView>
• contentInsetAdjustmentBehavior="automatic" should be applied to FlatList and SectionList
• Use flexbox instead of Dimensions API
• ALWAYS prefer useWindowDimensions over Dimensions.get()

Styling

• Prefer flex gap over margin and padding styles
• Prefer padding over margin where possible
• Inline styles not StyleSheet.create unless reusing styles is faster
• Use { borderCurve: 'continuous' } for rounded corners
• ALWAYS use a navigation stack title instead of a custom text element
• When padding a ScrollView, use contentContainerStyle padding
• Add entering and exiting animations for state changes

Shadows

Use CSS boxShadow style prop. NEVER use legacy React Native shadow or elevation styles.

<View style={{ boxShadow: "0 1px 2px rgba(0, 0, 0, 0.05)" }} />

Text Styling

• Add the selectable prop to every <Text/> element displaying important data
• Counters should use { fontVariant: 'tabular-nums' } for alignment

Safe Area

• Always account for safe area with stack headers, tabs, or ScrollView/FlatList contentInsetAdjustmentBehavior="automatic"
• Ensure both top and bottom safe area insets are accounted for

Navigation Patterns

Stack Configuration

import { Stack } from 'expo-router/stack';

<Stack
  screenOptions={{
    headerTransparent: true,
    headerShadowVisible: false,
    headerLargeTitleShadowVisible: false,
    headerLargeStyle: { backgroundColor: "transparent" },
    headerTitleStyle: { color: PlatformColor("label") },
    headerLargeTitle: true,
    headerBlurEffect: "none",
    headerBackButtonDisplayMode: "minimal",
  }}
>
  <Stack.Screen name="index" options={{ title: "Home" }} />
</Stack>

Links with Previews

import { Link } from 'expo-router';

<Link href="/settings">
  <Link.Trigger>
    <Pressable>
      <Card />
    </Pressable>
  </Link.Trigger>
  <Link.Preview />
  <Link.Menu>
    <Link.MenuAction title="Share" icon="square.and.arrow.up" />
    <Link.MenuAction title="Delete" icon="trash" destructive />
  </Link.Menu>
</Link>

Modal/Sheet Presentations

// Modal
<Stack.Screen name="modal" options={{ presentation: "modal" }} />

// Form Sheet
<Stack.Screen
  name="sheet"
  options={{
    presentation: "formSheet",
    sheetGrabberVisible: true,
    sheetAllowedDetents: [0.5, 1.0],
    contentStyle: { backgroundColor: "transparent" },
  }}
/>

Data Fetching

Environment Variables

• Use EXPO_PUBLIC_ prefix for client-side environment variables
• Never put secrets in EXPO_PUBLIC_ variables (visible in built app)
• Restart the dev server after changing .env files

# .env
EXPO_PUBLIC_API_URL=https://api.example.com
EXPO_PUBLIC_SUPABASE_URL=your-supabase-url

API Client Pattern

const BASE_URL = process.env.EXPO_PUBLIC_API_URL;

export const apiClient = {
  get: async <T,>(path: string): Promise<T> => {
    const response = await fetch(`${BASE_URL}${path}`);
    if (!response.ok) throw new Error(`HTTP ${response.status}`);
    return response.json();
  },
};

React Query Setup

// app/_layout.tsx
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";

const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      staleTime: 1000 * 60 * 5, // 5 minutes
      retry: 2,
    },
  },
});

EAS Build Configuration

{
  "cli": {
    "version": ">= 16.0.1",
    "appVersionSource": "remote"
  },
  "build": {
    "production": {
      "autoIncrement": true,
      "ios": {
        "resourceClass": "m-medium"
      }
    },
    "development": {
      "developmentClient": true,
      "distribution": "internal"
    }
  },
  "submit": {
    "production": {}
  }
}

Testing & Type Checking

# TypeScript
npx tsc --noEmit

# Run tests
npm test

# Lint
npx eslint .

Key Takeaways

1. Start simple: Always test in Expo Go before creating custom builds
2. Follow conventions: Use Expo Router patterns, kebab-case filenames
3. Use modern APIs: Prefer expo-audio, expo-video, expo-image
4. Handle safe areas: Use contentInsetAdjustmentBehavior="automatic"
5. Style with CSS: Use boxShadow instead of legacy shadow props
6. Type everything: Use TypeScript strict mode, no any
7. Secure tokens: Use expo-secure-store for sensitive data
8. Environment config: Use EXPO_PUBLIC_ prefix for client env vars

---

📝 Project Context

TabataFit — "Apple Fitness+ for Tabata"

• Framework: Expo SDK 52 (managed)
• Navigation: Expo Router v3
• State: Zustand + AsyncStorage
• Video: expo-av → HLS streaming
• Audio: expo-av (coaching + music)
• Animations: React Native Animated
• Payments: RevenueCat
• Analytics: PostHog

Design System

BACKGROUND: '#000000'    // Pure black
SURFACE: '#1C1C1E'       // Charcoal
BRAND: '#FF6B35'         // Flame orange
REST: '#5AC8FA'          // Ice blue
SUCCESS: '#30D158'       // Energy green

Phase Colors (Critical)

PREP: '#FF9500'    // Orange-yellow
WORK: '#FF6B35'    // Flame orange
REST: '#5AC8FA'    // Ice blue
COMPLETE: '#30D158' // Green

---

Last updated: March 14, 2026