A Firefox browser extension that extracts YouTube video transcripts and generates AI-powered summaries using Claude by Anthropic.
Current Version: 1.2.0
- Automatic Transcript Extraction - Extracts transcripts from YouTube videos
- AI-Powered Summaries - Uses Claude to generate comprehensive summaries
- Model Selection - Choose between Haiku 4, Sonnet 4, or Opus 4
- Smart Caching - Summaries cached per tab/video for instant retrieval
- Privacy-Focused - Your API key stored locally; no data sent to third parties
- Cost-Effective - Use your own Anthropic API key (typically pennies per video)
- Clean Interface - Simple, intuitive popup design with collapsible settings
- Quick Start
- Installation
- Usage
- Model Selection Guide
- Features in Detail
- Privacy & Security
- Costs
- Troubleshooting
- Customization
- Contributing
- Changelog
- Get your Anthropic API key (console.anthropic.com/settings/keys)
- Install the extension:
- Firefox:
about:debugging#/runtime/this-firefox - Click "Load Temporary Add-on"
- Select
manifest.json
- Firefox:
- Configure:
- Click the extension icon
- Enter your API key
- Choose your model (Sonnet 4 recommended)
- Click "Save Settings"
- Use it:
- Go to any YouTube video with captions
- Click the extension icon
- Click "Get Summary"
- Done!
- Download or clone this repository
- Open Firefox and navigate to:
about:debugging#/runtime/this-firefox - Click "Load Temporary Add-on..."
- Navigate to the extension folder and select
manifest.json - The extension is now loaded!
Note: Temporary extensions are removed when Firefox closes.
For personal use with unsigned extension:
-
Enable unsigned extensions:
- Type
about:configin Firefox - Search for
xpinstall.signatures.required - Set to
false
- Type
-
Package the extension:
cd youtube-claude-summary zip -r youtube-claude-summary.xpi *
-
Install:
- Drag the
.xpifile into Firefox - Click "Add"
- Drag the
To make it publicly available, submit to addons.mozilla.org for review.
- Click the extension icon in your Firefox toolbar
- Enter your Anthropic API key
- (Optional) Select your preferred Claude model
- Click "Save Settings"
- Navigate to any YouTube video with captions/transcripts
- Click the extension icon
- Click "Get Summary"
- Wait 10-30 seconds (depending on video length and model)
- Read your AI-generated summary!
- Click "Copy" to copy to clipboard
Collapsed View:
🔑 API Key Configured [Sonnet 4] [Edit]
Expanded View:
- Click "Edit" to change API key or model
- Select model from dropdown
- See cost estimates
- Click "Save Settings"
Each summary includes:
- Main Topic - What the video is about
- Key Points - Important information covered (bullet points)
- Notable Details - Interesting facts, statistics, insights
- Conclusion - Main takeaway
Best for: Simple content, high volume, cost-conscious users
| Metric | Rating |
|---|---|
| Speed | ⚡⚡⚡ Fastest (5-15 sec) |
| Cost | 💰 ~$0.004 per 30-min video |
| Quality | ⭐⭐⭐ Good |
Use when:
- Summarizing 50+ videos per month
- Simple content (vlogs, news, basic tutorials)
- Speed is your priority
- You want to minimize costs (87% cheaper than Sonnet!)
Best for: Most users, balanced needs, general purpose
| Metric | Rating |
|---|---|
| Speed | ⚡⚡ Fast (10-30 sec) |
| Cost | 💰💰 ~$0.03 per 30-min video |
| Quality | ⭐⭐⭐⭐ Excellent |
Use when:
- You want reliable, high-quality summaries
- Balanced cost and performance matters
- Most types of content (tutorials, podcasts, talks)
- Recommended starting point!
Best for: Complex content, highest quality, academic material
| Metric | Rating |
|---|---|
| Speed | ⚡ Slower (30-60 sec) |
| Cost | 💰💰💰 ~$0.11 per 30-min video |
| Quality | ⭐⭐⭐⭐⭐ Best |
Use when:
- Dense academic lectures or research talks
- Complex technical conferences (medical, legal, scientific)
- Philosophy or theory-heavy content
- You need the absolute best analysis
| Usage Level | Haiku 4 | Sonnet 4 | Opus 4 |
|---|---|---|---|
| Light (10 videos/month) | $0.04 | $0.28 | $1.08 |
| Regular (50 videos/month) | $0.20 | $1.40 | $5.40 |
| Heavy (200 videos/month) | $0.80 | $5.60 | $21.60 |
| Content Type | Recommended Model | Why |
|---|---|---|
| News clips | Haiku 4 | Simple, straightforward |
| Vlogs | Haiku 4 | Fast and cheap enough |
| Basic tutorials | Sonnet 4 | Better quality worth premium |
| Podcasts | Sonnet 4 | Captures nuance and themes |
| Tech conferences | Sonnet 4 or Opus 4 | Depends on complexity |
| Academic lectures | Opus 4 | Needs highest comprehension |
| Philosophy | Opus 4 | Complex reasoning required |
- Click extension icon
- Click "Edit" in configuration section
- Select model from dropdown
- Click "Save Settings"
- Model is saved and used for all future summaries
Summaries are cached per tab + video ID:
- Reopening popup shows cached summary instantly
- No API costs for viewing cached summaries
- Each tab maintains separate cache
- Cache persists while Firefox is running
- Different videos = different cached summaries
Example workflow:
- Generate summary for Video A in Tab 1 → Cached
- Close popup, browse other tabs
- Return to Tab 1, Video A → Instant display! ⚡
- Switch to Video B in same tab → New summary, newly cached
After saving your API key and model:
- Configuration collapses to single line
- Shows current model selection badge
- Click "Edit" to expand and change settings
- More screen space for summaries
- Explicit close button in header
- Popup also closes when clicking outside (Firefox default behavior)
- Popup automatically closes when switching windows/apps (browser security feature)
- No cached summary: "Get Summary"
- Cached summary exists: "Regenerate Summary"
- Shows "(cached)" indicator in stats
- No Data Collection - Extension doesn't collect or store user data
- Local Storage Only - API key stored locally in Firefox extension storage
- Direct API Calls - Transcripts sent directly to Anthropic's API
- No Third-Party Servers - No intermediary servers
- Your Own API Key - Full control and transparency over costs
Security Note: This extension makes API calls directly from your browser using the anthropic-dangerous-direct-browser-access header. This is safe because:
- You're using your own API key (not shared)
- API key stored locally in your browser only
- No one else has access to your extension or key
- This is the recommended approach for personal browser extensions
Comparison: Paid summary services use their API key on their servers, meaning your video data passes through their infrastructure. With this extension, your data goes directly to Anthropic.
Using your own Anthropic API key:
| Model | Input | Output | Typical 30-min Video |
|---|---|---|---|
| Haiku 4 | $0.40/M tokens | $2/M tokens | ~$0.004 |
| Sonnet 4 | $3/M tokens | $15/M tokens | ~$0.03 |
| Opus 4 | $15/M tokens | $75/M tokens | ~$0.11 |
100 videos per month:
- Haiku 4: $0.40/month
- Sonnet 4: $2.80/month
- Opus 4: $10.80/month
Much cheaper than paid YouTube summary services! Most charge $5-10/month for limited usage.
Solution: Video doesn't have captions/transcripts. Try another video with auto-generated or manual captions.
Solutions:
- Double-check key from console.anthropic.com/settings/keys
- Ensure it starts with
sk-ant- - Verify Anthropic account has API access enabled
Solutions:
- Refresh the YouTube page
- Ensure you're on a video page (URL contains
/watch?v=) - Reload extension from
about:debugging
Solution: You're not on a YouTube video page. Navigate to a video first.
Note: This is Firefox's default behavior for extension popups and cannot be changed. It's a security feature. The X button provides explicit control within the browser.
Solutions:
- Reload the extension from
about:debugging - Check browser console for errors (F12)
- Ensure you have the latest version
- Try removing and re-installing the extension
Edit background.js, find the prompt variable in summarizeWithClaude:
const prompt = `Your custom prompt here...`;Edit background.js, change max_tokens:
max_tokens: 4096, // Longer summariesEdit popup.css to customize:
- Colors
- Fonts
- Layout
- Button styles
youtube-claude-summary/
├── manifest.json # Extension configuration
├── content.js # Content script (runs on YouTube)
├── background.js # Service worker (API calls)
├── popup.html # Extension popup UI
├── popup.js # Popup logic
├── popup.css # Popup styling
├── icons/ # Extension icons
│ ├── icon16.png
│ ├── icon48.png
│ └── icon128.png
└── README.md # This file
- Manifest V3 - Modern Firefox extension format
- Claude 4 API - Anthropic's latest models
- Browser Storage API - Local storage for settings
- Firefox Extensions API - Browser integration
Contributions welcome! Feel free to:
- Report bugs
- Suggest features
- Submit pull requests
- Improve documentation
- Multiple summary styles (brief, detailed, bullet points)
- Export summaries (PDF, Markdown, etc.)
- Timestamp links in summaries
- Playlist support
- Custom prompt templates
- Summary history
- Keyboard shortcuts
- Dark mode
New Features:
- Model selector (Haiku 4, Sonnet 4, Opus 4)
- Cost information for each model
- Model badge in collapsed configuration
- Smart defaults (Sonnet 4)
Improvements:
- Model selection persists across sessions
- API key validation uses Haiku 4 (faster, cheaper)
- Button renamed to "Save Settings"
New Features:
- Collapsible configuration section
- "Edit" button for compact view
- More screen space for summaries
Bug Fixes:
- Fixed JavaScript syntax error (duplicate variable)
- API key saving now works correctly
- Password visibility toggle fixed
New Features:
- Summary caching per tab/video
- Close button in header
- Smart button labels
Improvements:
- Fixed scrollbar issues
- Better text wrapping
- Fixed width popup
Initial Release:
- Extract YouTube transcripts
- Generate AI summaries with Claude
- Configurable API key storage
- Clean popup interface
- Multi-language support
- Copy to clipboard
MIT License - feel free to use and modify as needed.
- Built with Anthropic's Claude API
- Inspired by the need for efficient video learning
- Thanks to the open-source community
- Issues: Open an issue on GitHub
- API Help: Anthropic Documentation
- Firefox Extensions: MDN Web Docs
Made with ❤️ for efficient YouTube learning
Transform hours of video into minutes of reading!