Stitch React Native

Stitch to React Native Components

You are a mobile engineer focused on transforming Stitch web designs into clean, production-ready React Native code or syncing/updating existing native components to align with the latest Stitch designs. You translate HTML/CSS layouts into native mobile components using React Native primitives and StyleSheet.

CRITICAL: Every step in this skill is MANDATORY. Do NOT skip any step or take shortcuts. Each section contains a GATE that must be satisfied before proceeding.

Phase 1: Retrieval and networking

GATE: Phase 1 is complete ONLY when all screens have been downloaded via scripts/fetch-stitch.sh AND visually audited. Reading local files directly without going through this phase is PROHIBITED.

1. Namespace discovery: Run list_tools to find the Stitch MCP prefix. Use this prefix (e.g., stitch:) for all subsequent calls.
2. Metadata fetch: Call [prefix]:get_screen for EVERY screen in the project to retrieve the design JSON with download URLs. Do NOT skip any screen.
3. Check for existing designs: Before downloading, check if .stitch/designs/{page}.html and .stitch/designs/{page}.png already exist:
   • If files exist: Ask the user whether to refresh the designs from the Stitch project using the MCP, or reuse the existing local files. You MUST ask — do not assume. Only re-download if the user confirms.
   • If files do not exist: Proceed to step 4.
4. High-reliability download: Internal AI fetch tools can fail on Google Cloud Storage domains. You MUST use the provided script.
   • HTML: bash scripts/fetch-stitch.sh "[htmlCode.downloadUrl]" ".stitch/designs/{page}.html"
   • Screenshot: Append =w{width} to the screenshot URL first, where {width} is the width value from the screen metadata (Google CDN serves low-res thumbnails by default). Then run: bash scripts/fetch-stitch.sh "[screenshot.downloadUrl]=w{width}" ".stitch/designs/{page}.png"
   • This script handles the necessary redirects and security handshakes.
5. Visual audit: Review the downloaded screenshot (.stitch/designs/{page}.png) to confirm design intent and layout details. You MUST view each screenshot — do not proceed based on assumptions about the design.
6. Project metadata tracking: Retrieve project configuration using [prefix]:get_project and save it to .stitch/metadata.json (inside the app folder, and mirrored in the workspace root). Ensure it has:
   • projectId, title, deviceType
   • A Last Sync Time field matching the current sync ISO execution time
   • A screens map detailing each screen's ID, label, sourceScreen reference, dimensions, and canvasPosition.

Anti-patterns for Phase 1

• ❌ Reading .stitch/designs/*.html directly without calling MCP get_screen first.
• ❌ Skipping the fetch-stitch.sh download script.
• ❌ Not asking the user when existing files are found.
• ❌ Skipping the visual audit of .png screenshots.
• ❌ Failing to generate or update .stitch/metadata.json and its Last Sync Time field upon syncing.

Phase 2: Theme extraction

GATE: Phase 2 is complete ONLY when src/theme.ts has been created or updated with tokens extracted from the current project's HTML <head>. Hardcoding color hex codes or using themes from a different project is NOT acceptable.

1. Extract tailwind.config: Open each downloaded HTML file and locate the tailwind.config object in the <head> <script> block. Extract:
   • All color tokens
   • Font families
   • Spacing values
   • Border radius values
   • Font size/typography tokens
2. Create/Sync src/theme.ts: Write the extracted tokens to src/theme.ts as TypeScript constants. Ensure every color, spacing, and typography value has a corresponding token.
3. Verify theme: Confirm the theme colors and fonts in src/theme.ts match what you extracted from the HTML design.

Anti-patterns for Phase 2

• ❌ Hardcoding color hex codes or rgba strings directly inside component StyleSheet declarations.
• ❌ Using theme tokens from a previous project without extracting them from the new design.
• ❌ Skipping the creation/update of src/theme.ts.

Phase 3: Architectural rules and HTML mapping

GATE: Every component MUST satisfy ALL of the following rules. Violations will cause npm run validate to fail.

Element mapping

Map HTML elements to React Native components using these rules:

Style mapping

CSS and Tailwind classes do not work in React Native. Convert all styles to StyleSheet.create():

• Layout: Flexbox is the default layout system. flexDirection defaults to 'column' (not 'row' like web CSS).
  • display: flex is implicit on every View.
  • justify-content maps to justifyContent.
  • align-items maps to alignItems.
  • gap maps to gap (React Native 0.71+). For older versions, use marginBottom on children.
• Dimensions: Use numbers (not strings). width: 100 means 100 density-independent pixels.
  • Percentage strings are supported: width: '100%'.
  • For responsive sizing, use useWindowDimensions() from react-native.
  • There is no vw/vh. Calculate from Dimensions.get('window').
• Typography: All text styles must be on Text components, never on View.
  • font-size maps to fontSize (number, not string).
  • font-weight maps to fontWeight (string: '400', '700', 'bold').
  • line-height maps to lineHeight (number).
  • letter-spacing maps to letterSpacing.
  • text-transform maps to textTransform.
  • color applies to Text only.
• Borders and shadows:
  • border-radius maps to borderRadius.
  • box-shadow does not exist. Use elevation (Android) and shadowColor/shadowOffset/shadowOpacity/shadowRadius (iOS). Use Platform.select() to apply platform-specific shadow styles.
• Unsupported CSS properties: Do not use hover, transition, animation (use react-native-reanimated for animations), or position: fixed (use absolute positioning instead).

Architectural Rules

• Modular components (Atomic Design): Break the design into independent files. Organize components as atoms (buttons, labels, icons), molecules (input groups, cards), and organisms (headers, lists, forms). Place them in src/components/atoms/, src/components/molecules/, and src/components/organisms/. Monolithic page/screen files are PROHIBITED.
• Logic isolation: Move event handlers, API calls, and business logic into custom hooks in src/hooks/. Components should only handle rendering.
• Data decoupling: Move ALL static text, image URLs, and lists into src/data/mockData.ts. No hardcoded content in components.
• Type safety: EVERY component file (including screens) MUST export a TypeScript interface named [ComponentName]Props with readonly property modifiers. The validator requires the interface to be exported — files without an exported Props interface will FAIL validation.
• No hardcoded styles: Extract colors, spacing, and font sizes into src/theme.ts. Reference them in StyleSheet.create(). Absolutely no raw color hex codes or rgba strings are allowed in component files.
• Navigation: Use React Navigation for screen transitions. Define screen types with NativeStackScreenProps or BottomTabScreenProps.
• Accessibility: Every interactive element must have accessibilityLabel and accessibilityRole. Images need accessibilityLabel. Use accessibilityState for toggles and checkboxes.
• Safe areas: Wrap top-level screen components with SafeAreaView from react-native-safe-area-context (not the default one from react-native).
• Project specific: Focus on the target project's needs and constraints. Leave Google license headers out of the generated components.

Platform-specific code

When the design requires different behavior on iOS and Android:

import { Platform } from 'react-native';

const styles = StyleSheet.create({
  shadow: Platform.select({
    ios: {
      shadowColor: '#000',
      shadowOffset: { width: 0, height: 2 },
      shadowOpacity: 0.1,
      shadowRadius: 4,
    },
    android: {
      elevation: 4,
    },
  }),
});

Anti-patterns for Phase 3

• ❌ Putting all UI in a single monolithic screen file.
• ❌ Using HTML tags (like div, span, p) instead of React Native components.
• ❌ Inline event handlers or business logic without custom hooks.
• ❌ Hardcoding text, URLs, or colors in component files.
• ❌ Components without an exported [Name]Props interface.
• ❌ Using raw hex color values or rgba strings in StyleSheet.create().

Phase 4: Execution steps

GATE: Phase 4 verification, audits, and simulator/packager testing are optional. You MUST ask the user's permission to proceed with validation scripts, starting packagers, or simulator audits.

1. Environment setup: If node_modules is missing, run npm install to enable the validation tools.
2. Theme layer: Create src/theme.ts from the extracted Tailwind config.
3. Data layer: Create src/data/mockData.ts based on the design content.
4. Component drafting: Use resources/component-template.tsx as a base. Find and replace ALL instances of StitchComponent with the actual component name. Map HTML elements to React Native primitives.
5. Navigation wiring: If the design has multiple screens, set up a NavigationContainer with a stack or tab navigator in App.tsx.
6. Quality check (Optional - Ask User first):
   • Run npm run validate <file_path> for EVERY .tsx file in components and screens to report component validity.
   • Run tsc --noEmit to verify TypeScript compile status.
   • Check output against resources/architecture-checklist.md.
   • Obtain permission before starting the packager (npx react-native start or npx expo start) or starting visual simulator audits to verify the app renders correctly on a simulator/device.

Anti-patterns for Phase 4

• ❌ Launching packagers or simulators without user consent.
• ❌ Declaring task "done" without verifying code compiles.

Troubleshooting

• Fetch errors: Ensure the URL is quoted in the bash command to prevent shell errors.
• Validation errors: Review the AST report and fix any missing interfaces or hardcoded styles. The most common failures are missing an exported Props interface or leaving raw hex colors in StyleSheet.create().
• Text outside Text component: React Native crashes if raw strings appear outside <Text>. Verify all text nodes are wrapped.
• Image sizing: Unlike web <img>, React Native Image has no intrinsic size. Always specify width and height in styles or use aspectRatio.
• FlatList vs ScrollView: If you see a "VirtualizedList inside ScrollView" warning, replace the outer ScrollView with a plain View or use FlatList ListHeaderComponent/ListFooterComponent.