naively

A minimal TypeScript wrapper around Chrome Built-in AI APIs.

Status

Chrome Built-in AI APIs are actively shipping. As of Chrome 138 (stable):

| API | Status | Supported | |-----|--------|-----------| | Summarizer | ✅ Stable | ✅ | | Translator | ✅ Stable | ✅ | | Language Detector | ✅ Stable | ✅ | | Writer / Rewriter | 🧪 Developer Trial | Soon | | Prompt API (web) | 🔬 Origin Trial | Soon |

These APIs run a local Gemini Nano model on the user's device — no API key or network request required after the initial model download.

Requirements

• Browser: Chrome 138+ (desktop only — not supported on Android or iOS)
• OS: Windows 10+, macOS 13+, Linux, or ChromeOS (Chromebook Plus)
• Storage: ~22 GB free disk space (for the model)
• Hardware: GPU with 4 GB+ VRAM, or CPU with 16 GB RAM and 4+ cores

Installation

pnpm add naively
# or
npm install naively

Usage

Check support

import { getAiSupport, isSummarizerSupported, isTranslatorSupported, isLanguageDetectorSupported } from 'naively'

// Quick boolean checks
isSummarizerSupported()       // true | false
isTranslatorSupported()       // true | false
isLanguageDetectorSupported() // true | false

// Full support details
const support = await getAiSupport()
// {
//   summarizer:       { supported: true, availability: 'readily' | 'downloadable' | 'unavailable' | 'unsupported' }
//   translator:       { supported: true }
//   languageDetector: { supported: true, availability: 'readily' | 'downloadable' | 'unavailable' | 'unsupported' }
// }

Translator availability is language-pair specific — naively checks it internally when you call translate().

Summarizer availability values:

| Value | Meaning | |-------|---------| | readily | Model is downloaded and ready | | downloadable | Supported, but model needs to download first | | unavailable | Hardware/OS doesn't meet requirements | | unsupported | API not present in this browser |

Summarize text

import { summarize } from 'naively'

const result = await summarize(articleText)

if (result.ok) {
  console.log(result.data)
} else {
  console.error(result.error?.message)
}

With options:

const result = await summarize(articleText, {
  type: 'key-points',   // 'tl;dr' | 'key-points' | 'teaser' | 'headline'
  length: 'medium',     // 'short' | 'medium' | 'long'
  format: 'plain-text', // 'plain-text' | 'markdown'
})

Translate text

Language codes follow the BCP 47 format (e.g. 'en', 'fr', 'es', 'ja').

import { translate } from 'naively'

const result = await translate('Hello, world!', {
  sourceLanguage: 'en',
  targetLanguage: 'fr',
})

if (result.ok) {
  console.log(result.data) // 'Bonjour, le monde !'
} else {
  console.error(result.error?.message)
}

API Reference

summarize(text, options?): Promise<SummarizeResult>

| Option | Type | Default | |--------|------|---------| | type | 'tl;dr' \| 'key-points' \| 'teaser' \| 'headline' | 'key-points' | | length | 'short' \| 'medium' \| 'long' | 'medium' | | format | 'plain-text' \| 'markdown' | 'plain-text' |

detectLanguage(text): Promise<DetectLanguageResult>

Returns a ranked list of language candidates with confidence scores (0.0–1.0):

const result = await detectLanguage('Bonjour le monde')

if (result.ok) {
  console.log(result.data)
  // [
  //   { detectedLanguage: 'fr', confidence: 0.998 },
  //   { detectedLanguage: 'en', confidence: 0.001 },
  // ]
}

Accuracy is low for very short text or single words.

translate(text, options): Promise<TranslateResult>

| Option | Type | Required | |--------|------|----------| | sourceLanguage | string (BCP 47) | ✅ | | targetLanguage | string (BCP 47) | ✅ |

getAiSupport()

Returns support and availability details for all built-in AI APIs.

isSummarizerSupported() / isTranslatorSupported(): boolean

Synchronous presence checks.

Both summarize() and translate() always return a result without throwing:

interface SummarizeResult {
  ok: boolean
  data?: string
  error?: { code: string; message: string }
}

interface TranslateResult {
  ok: boolean
  data?: string
  error?: { code: string; message: string }
}

Edge cases handled internally: empty text, API not present, model unavailable, creation/runtime errors, and model cleanup (destroy()).

Development

pnpm install
pnpm build      # outputs to dist/
pnpm typecheck  # tsc --noEmit

Further Reading

• Chrome Built-in AI overview
• Summarizer API docs
• Translator API docs
• Language Detector API docs
• People + AI Guidebook — UX guidance for AI features
• @types/dom-chromium-ai — official TypeScript types for Chrome AI APIs