Feat/2 apis integration

[simandebvu]

Implement Core Utilities for Chrome's Built-in AI APIs

📋 Summary

Complete implementation of TypeScript wrappers for Chrome's three built-in AI APIs (Rewriter, Translator, Prompt/Language Model) with comprehensive error handling, browser compatibility detection, and interactive demo pages.

Closes: Backlog card - "Implement core utilities for Chrome's Built-in AI APIs with proper error handling"

---

✅ Acceptance Criteria Met

• ✅ All three APIs have utility wrappers - Complete implementations with high-level service classes and low-level wrappers
• ✅ Browser compatibility is checked on load - Full detection system with compatibility banner
• ✅ Clear error messages for unavailable APIs - Custom error classes with 25+ error codes
• ✅ API availability detection - Runtime capability detection for all APIs
• ✅ Graceful fallback messaging - Browser compatibility checks and user-friendly messages
• ✅ Loading states and progress indicators - Real-time download progress visualization

---

🎯 Tasks Completed

1. ✅ Create Chrome Rewriter API Wrapper

Implementation:

• Low-level wrappers: createRewriter(), rewriteText(), rewriteTextStreaming()
• RewriterService class with reading level presets
• Content chunking for long text
• Retry logic with exponential backoff
• Input validation and sanitization
• Enhanced: Download progress monitoring

Files: rewriter.ts, services/RewriterService.ts, test/RewriterTest.tsx

2. ✅ Create Chrome Prompt API Wrapper

Implementation:

• Low-level wrappers: createSession(), sendPrompt(), sendPromptStreaming()
• PromptService class with conversation management
• System prompts and context handling
• Temperature and Top-K configuration
• Multimodal support (text, images, audio)
• Session cloning and history tracking
• Download progress monitoring

Files: prompt.ts, services/PromptService.ts, test/PromptTest.tsx

3. ✅ Create Chrome Translation API Wrapper

Implementation:

• Low-level wrappers: createTranslator(), translateText(), detectLanguage()
• TranslatorService class with auto-detection
• Language detection with confidence scores
• Support for multiple language pairs (BCP 47)
• Streaming translation
• Auto-detect and translate workflow
• Download progress monitoring

Files: translator.ts, services/TranslatorService.ts, test/TranslatorTest.tsx

4. ✅ Implement API Availability Detection

Implementation:

• capabilities.ts - Runtime availability checking for all APIs
• ChromeAiDiagnostics component - Visual diagnostics dashboard
• Checks three states: unavailable, available, downloadable
• Model availability status display
• Environment validation

Files: capabilities.ts, test/ChromeAiDiagnostics.tsx

5. ✅ Add Graceful Fallback Messaging

Implementation:

• browserCompatibility.ts - Browser detection and version checking
• BrowserCompatibilityBanner component - Requirements display
• Chrome version validation (137+ required)
• Flag configuration guidance
• Clear setup instructions
• User-friendly error messages

Files: browserCompatibility.ts, common/BrowserCompatibilityBanner.tsx

6. ✅ Add Loading States and Progress Indicators

Implementation:

• ModelDownloadProgress component - Download visualization
• Real-time progress bars with percentages
• Byte count display (e.g., "1.5 MB / 2.3 MB")
• Status messages: Checking → Downloading → Ready
• Monitor callbacks integrated into all services
• 8 UI components: LoadingSpinner, ProgressBar, Skeleton variants

Files: ui/ModelDownloadProgress.tsx, ui/LoadingSpinner.tsx, ui/ProgressBar.tsx, ui/Skeleton.tsx

---

🏗️ Architecture

Three-Layer Design

┌─────────────────────────────────┐
│ Service Layer (Business Logic) │
│ - RewriterService               │
│ - TranslatorService             │
│ - PromptService                 │
└─────────────────────────────────┘
              ↓
┌─────────────────────────────────┐
│ Wrapper Layer (API Interaction) │
│ - rewriter.ts                   │
│ - translator.ts                 │
│ - prompt.ts                     │
└─────────────────────────────────┘
              ↓
┌─────────────────────────────────┐
│ Chrome AI Native APIs           │
│ - self.Rewriter                 │
│ - self.Translator               │
│ - self.LanguageModel            │
└─────────────────────────────────┘

---

📊 Implementation Stats

• 36 files changed
• 6,287 lines added
• 3 complete API wrappers
• 3 service classes (high-level)
• 3 error classes (25 error codes)
• 8 UI components
• 3 interactive test pages
• 1 central demos landing page

---

🎨 Key Features

Error Handling

• RewriterError - 8 error codes (NOT_AVAILABLE, NOT_SUPPORTED, etc.)
• TranslatorError - 9 error codes (UNSUPPORTED_LANGUAGE, etc.)
• PromptError - 8 error codes (PROMPT_FAILED, RESPONSE_ERROR, etc.)
• Type guards for error checking
• Automatic retry for retryable errors
• Detailed error messages with context

Browser Compatibility

• Runtime browser detection
• Chrome version validation (137+ required)
• Flag configuration checklist
• Compatibility banner with setup instructions
• Model download status checking

Progress Tracking

• Visual progress bars during model downloads
• Percentage indicators (0-100%)
• Byte count display with human-readable format
• Status messages throughout lifecycle
• Monitor callbacks in all service classes

Type Safety

• Full TypeScript implementation
• Comprehensive type definitions
• Type inference for all operations
• No any types used
• Proper error type guards

---

🧪 Testing

Build Status

✅ TypeScript compilation successful
✅ ESLint: 0 errors, 0 warnings
✅ Vite build successful
✅ Bundle: 371 kB (109 kB gzipped)

Manual Testing

✅ All three APIs tested in Chrome Canary
✅ Browser compatibility detection working
✅ Download progress visualization verified
✅ Error handling validated
✅ Fallback messages displayed correctly
✅ Loading states functioning properly

---

💡 Usage Examples

Rewriter API

import { RewriterService } from '@/lib/chrome-ai';

const service = new RewriterService({
  language: 'en',
  monitor: (progress) => {
    console.log(`Downloading: ${progress.loaded}/${progress.total} bytes`);
  }
});

await service.initialize();
const simplified = await service.simplify(text, {
  readingLevel: 'elementary'
});
service.destroy();

Translator API

import { TranslatorService } from '@/lib/chrome-ai';

const service = new TranslatorService({
  minConfidence: 0.5,
  monitor: (progress) => showProgress(progress)
});

// Auto-detect and translate
const result = await service.detectAndTranslate('Hello world', 'es');
console.log(result); // { detectedLanguage: 'en', translatedText: 'Hola mundo' }

Prompt API

import { PromptService } from '@/lib/chrome-ai';

const service = new PromptService({
  temperature: 0.7,
  initialPrompts: [{ role: 'system', content: 'You are helpful.' }],
  monitor: (progress) => showProgress(progress)
});

await service.initialize();
const response = await service.prompt('What is TypeScript?');

---

🎮 Demo Pages

Central Landing Page (/demos)

• Overview of all three APIs
• Status badges (Available/Coming Soon/Planned)
• Feature lists and documentation links
• Requirements banner

Interactive Test Pages

1. Rewriter Demo (/demos/rewriter) - Text simplification with reading levels
2. Translator Demo (/demos/translator) - Translation with language detection
3. Prompt Demo (/demos/prompt) - Conversational AI interface

All demos include:

• Live diagnostics dashboard
• Browser compatibility checks
• Download progress visualization
• Event logging
• Error handling demonstrations

---

📂 Files Added/Modified

New Core Files

src/lib/chrome-ai/
├── services/
│   ├── PromptService.ts      [NEW] 401 lines
│   ├── TranslatorService.ts  [NEW] 465 lines
│   └── RewriterService.ts    [ENHANCED]
├── errors/
│   ├── PromptError.js        [NEW]
│   ├── TranslatorError.js    [NEW]
│   └── errorMessages.ts      [NEW] 183 lines
├── prompt.ts                 [NEW] 323 lines
├── translator.ts             [NEW] 441 lines
├── browserCompatibility.ts   [NEW] 239 lines
├── capabilities.ts           [NEW] 134 lines
└── types.ts                  [ENHANCED +408 lines]

New UI Components

src/components/ui/
├── ModelDownloadProgress.tsx [NEW] 161 lines
├── LoadingSpinner.tsx        [NEW] 149 lines
├── ProgressBar.tsx           [NEW] 345 lines
└── Skeleton.tsx              [NEW] 212 lines

Test Infrastructure

src/components/test/
├── PromptTest.tsx            [NEW] 512 lines
├── TranslatorTest.tsx        [NEW] 542 lines
├── RewriterTest.tsx          [ENHANCED]
└── ChromeAiDiagnostics.tsx   [ENHANCED]

src/pages/
└── DemosPage.tsx             [NEW] 279 lines

---

🚀 Technical Highlights

Performance

• Automatic content chunking for long text
• Streaming support for all APIs
• Retry with exponential backoff
• Efficient resource management

Reliability

• Comprehensive error handling
• Browser compatibility validation
• Graceful degradation
• Clear user feedback

Developer Experience

• Full TypeScript support
• Interactive test pages
• Live diagnostics dashboard
• Extensive inline documentation

User Experience

• Download progress visualization
• Real-time status updates
• Clear error messages
• Responsive UI components
• Accessible design (ARIA labels)

---

🔗 Related

Branch: feat/2-apis-integration
Base: main

Chrome Requirements:

• Chrome Canary/Dev 137+
• Flags: optimization-guide-on-device-model, prompt-api-for-gemini-nano
• Model download may be required

---

✅ Checklist

• All three API wrappers implemented
• Browser compatibility detection added
• Clear error messages for unavailable APIs
• API availability detection functional
• Graceful fallback messaging implemented
• Loading states and progress indicators working
• TypeScript compilation successful
• ESLint passing (0 errors, 0 warnings)
• Build successful
• Manual testing completed
• Demo pages functional
• Documentation inline with code

---

Ready for review! 🎉

This PR delivers a production-ready, type-safe implementation of Chrome's Built-in AI APIs with comprehensive error handling, browser compatibility detection, and excellent developer experience.

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Project	Deployment	Preview	Comments	Updated (UTC)
synapse	Ready	Preview	Comment	Oct 14, 2025 3:33pm

[seshxn]

@simandebvu Awesome stuff!!! I am having some issues with the setup locally, but it should be resolved soon 👍

Are you also able to update the .env.example with the new environment variable placeholders?