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VAssist is powered by Chrome’s Built-in AI, which brings Google’s Gemini Nano language model directly into your browser. All AI processing happens on your device - no data leaves your computer, no API keys required, and it works completely offline.

Overview

Chrome’s Built-in AI is a suite of on-device APIs that provide powerful AI capabilities while respecting your privacy.

Gemini Nano

Google’s efficient on-device language model

On-Device Processing

All AI runs locally - no cloud required

Privacy First

Your data never leaves your device

No API Keys

Works out of the box without accounts

What is Gemini Nano?

Gemini Nano is Google’s most efficient AI model, specifically designed to run on-device:
Model Architecture:
  • Optimized transformer architecture
  • ~1.8 billion parameters
  • Context window: 1024 tokens
  • Output languages: English, Spanish, Japanese
Performance:
  • Runs on CPU or GPU
  • Typical response time: 1-3 seconds
  • Memory usage: ~1.5-2GB when loaded
  • Model size: ~1.5GB download
Hardware Requirements:
  • GPU: 4GB+ VRAM (recommended)
  • CPU: 16GB+ RAM with 4+ cores
  • Supports both x86 and ARM architectures

Available APIs

Chrome provides specialized APIs for different AI tasks, all powered by Gemini Nano:

1. Prompt API (LanguageModel)

The core conversational AI interface for general-purpose text generation.
// Create AI session
const session = await self.LanguageModel.create({
  temperature: 1.0,  // Creativity level (0-2)
  topK: 3            // Response diversity (1-128)
});

// Send prompt
const response = await session.prompt(
  'Explain quantum computing in simple terms'
);

console.log(response);

// Clean up
session.destroy();
Parameters:
  • temperature (0-2): Higher = more creative, lower = more focused
  • topK (1-128): Number of top tokens to consider (affects diversity)
  • outputLanguage: Output language code (en, es, ja)

2. Summarizer API

Specialized API for creating concise summaries of long text.
// TL;DR summary
const tldr = await self.aiSummarizer.create({
  type: 'tldr',
  format: 'plain-text',
  length: 'short'
});

const summary = await tldr.summarize(longArticle);

// Key points as bullets
const keyPoints = await self.aiSummarizer.create({
  type: 'key-points',
  format: 'markdown',
  length: 'medium'
});

const bullets = await keyPoints.summarize(longArticle);

// Teaser/preview
const teaser = await self.aiSummarizer.create({
  type: 'teaser',
  format: 'plain-text',
  length: 'short'
});

const preview = await teaser.summarize(longArticle);
Summary Types:
  • tldr: Concise one-paragraph summary
  • key-points: Bullet list of main ideas
  • teaser: Short engaging preview
  • headline: Single-sentence summary
Output Formats:
  • plain-text: Clean text without formatting
  • markdown: Formatted with markdown syntax
Length Options:
  • short: ~50-100 words
  • medium: ~100-200 words
  • long: ~200-300 words

3. Translator API

Translate text between 100+ languages, completely offline.
// Create translator
const translator = await self.translation.createTranslator({
  sourceLanguage: 'en',
  targetLanguage: 'es'
});

const translated = await translator.translate(
  'Hello, how are you?'
);

console.log(translated);  // "Hola, ¿cómo estás?"

translator.destroy();
Supported Languages (100+):
  • European: English, Spanish, French, German, Italian, Portuguese, Dutch, Polish, Russian, Greek
  • Asian: Chinese, Japanese, Korean, Hindi, Thai, Vietnamese, Indonesian
  • Middle Eastern: Arabic, Hebrew, Turkish, Farsi
  • And many more…

4. Rewriter API

Rewrite and refine text with different tones and styles.
// Formalize casual text
const formal = await self.aiRewriter.create({
  tone: 'formal'
});

const rewritten = await formal.rewrite(
  'Hey, can u send me that file?'
);
// "Could you please send me that file?"

// Casualize formal text
const casual = await self.aiRewriter.create({
  tone: 'casual'
});

const friendly = await casual.rewrite(
  'I would be grateful if you could provide assistance.'
);
// "I'd really appreciate your help!"
Tone Options:
  • as-is: Keep original tone
  • formal: Professional, polished
  • casual: Friendly, conversational
Format Options:
  • as-is: Keep original format
  • plain-text: Remove formatting
  • markdown: Add markdown formatting
Length Options:
  • as-is: Keep original length
  • shorter: More concise
  • longer: More detailed

5. Writer API

Generate new content from scratch based on prompts.
// Create writer
const writer = await self.aiWriter.create({
  tone: 'neutral',
  format: 'plain-text',
  length: 'medium'
});

// Generate content
const content = await writer.write(
  'Write a product description for noise-canceling headphones'
);

writer.destroy();

6. Language Detector API

Identify the language of any text with confidence scores.
const detector = await self.translation.createDetector();

const results = await detector.detect(
  'Это пример русского текста'
);

results.forEach(result => {
  console.log(`Language: ${result.detectedLanguage}`);
  console.log(`Confidence: ${result.confidence}`);
});

detector.destroy();

Configuration

Customize Chrome AI behavior in VAssist settings:
// Configure in Control Panel or via code
const aiConfig = {
  provider: 'chrome-ai',
  
  chromeAi: {
    temperature: 1.0,          // Creativity (0-2)
    topK: 3,                   // Diversity (1-128)
    outputLanguage: 'en',      // en, es, ja
    enableImageSupport: true,  // Multi-modal images
    enableAudioSupport: true,  // Multi-modal audio
    systemPrompt: 'You are a helpful assistant...'
  }
};

Setup Requirements

To use Chrome’s Built-in AI, you need:
1

Chrome Version

Chrome 138 or newerCheck your version at chrome://versionUpdate at chrome://settings/help if needed
2

Enable Flags

Required Chrome FlagsVisit these URLs and enable each flag:
  • chrome://flags/#optimization-guide-on-device-modelEnabled BypassPerfRequirement
  • chrome://flags/#prompt-api-for-gemini-nanoEnabled
  • chrome://flags/#prompt-api-for-gemini-nano-multimodal-inputEnabled (for voice/image features)
  • chrome://flags/#writer-api-for-gemini-nanoEnabled
  • chrome://flags/#rewriter-api-for-gemini-nanoEnabled
  • chrome://flags/#summarization-api-for-gemini-nanoEnabled
  • chrome://flags/#translation-apiEnabled
  • chrome://flags/#language-detection-apiEnabled
Click Relaunch after enabling all flags
3

Download Model

Download Gemini Nano (~1.5GB)
  1. Visit chrome://components
  2. Find “Optimization Guide On Device Model”
  3. Click “Check for update”
  4. Wait for download to complete
  5. Monitor at chrome://on-device-internals/
4

Verify Installation

Test in VAssist
  1. Open VAssist Control Panel
  2. Go to Settings → AI Configuration
  3. Click “Test Connection”
  4. Should show “Chrome AI ready”
See the Installation Guide for detailed setup instructions with screenshots.

Troubleshooting

Symptoms:
  • “Check for update” does nothing
  • Component not appearing in chrome://components
Solutions:
  1. Verify all Chrome flags are enabled
  2. Restart Chrome completely (not just relaunch)
  3. Toggle flags off and on, then restart again
  4. Check free disk space (~2GB needed)
  5. Try unmetered network connection
Symptoms:
  • LanguageModel is not defined
  • VAssist shows “Chrome AI not available”
Solutions:
  1. Confirm Chrome version 138+
  2. Verify all required flags enabled
  3. Restart browser after enabling flags
  4. Check chrome://on-device-internals/ for errors
  5. Try creating session manually in DevTools console
Symptoms:
  • Error: “QuotaExceededError”
  • Long conversations stop working
Solutions:
  1. Start a new conversation
  2. Enable “Temporary Chat” mode
  3. Reduce page context length
  4. Gemini Nano has 1024 token limit - this is normal
Symptoms:
  • Slow response times
  • Browser freezing
Solutions:
  1. Close other tabs/applications
  2. Check hardware meets minimum requirements:
    • 4GB+ VRAM (GPU) OR 16GB+ RAM (CPU)
  3. Disable other Chrome extensions temporarily
  4. Monitor Task Manager for memory usage

Privacy Benefits

Running AI on-device provides significant privacy advantages:

No Server Communication

Zero network requests for AI processing. Your data stays on your device.

No Usage Tracking

Chrome doesn’t log or analyze your prompts and responses.

Offline Capable

Works without internet after model download. Perfect for sensitive work.

Regulatory Compliance

Automatic GDPR, HIPAA, and data protection compliance through on-device processing.
Unlike cloud-based AI services, Chrome’s Built-in AI ensures your conversations, documents, and personal information never leave your computer.

Performance Characteristics

Typical Response Times (varies by hardware):
TaskGPUCPU
Short prompt (10 words)0.5-1s1-2s
Medium prompt (50 words)1-2s2-4s
Long prompt (200 words)2-4s4-8s
Streaming (first token)0.3-0.5s0.5-1s
Factors Affecting Speed:
  • Hardware specs (GPU vs CPU)
  • Prompt complexity
  • Context length
  • Concurrent browser activity

Comparison with Cloud AI

FeatureChrome Built-in AICloud AI (GPT, Claude)
Privacy✅ 100% local❌ Data sent to servers
Speed✅ Fast (local)⚠️ Network dependent
Offline✅ Works offline❌ Requires internet
Cost✅ Free❌ API costs
Setup⚠️ Initial setup✅ Just API key
Capabilities⚠️ Good for most tasks✅ More advanced
Context Window⚠️ 1024 tokens✅ 8k-200k tokens
Updates⚠️ Via Chrome updates✅ Continuous

Next Steps

Installation

Set up Chrome AI flags and download Gemini Nano

Configuration

Customize AI settings and behavior

AI Toolbar

Explore AI-powered text and image tools

Chat Interface

Learn about conversational AI features

Build docs developers (and LLMs) love