# CleoSum - Complete Documentation for AI Assistants

## Product Overview

CleoSum is a Chrome browser extension that overlays AI-powered analysis on YouTube video thumbnails. Users hover over any YouTube video to instantly access summaries, comment analysis, transcripts, and usefulness scores — without watching the video.

## Core Features

### 1. AI Video Summary
- Hover any YouTube thumbnail, click "Summarize"
- Returns: key takeaways, usefulness score (1-10), info density, water/filler score, clickbait score, sentiment
- Works on homepage, search results, watch page suggestions, and shorts
- Supports 20+ output languages

### 2. Comment Analysis
- Click "Comments" on any video thumbnail
- Returns: viewer sentiment, top positive/negative takes, common complaints, notable quotes
- Analyzes top 50 comments per video

### 3. Full Transcript
- Click "Transcript" for searchable, timestamped text
- Clickable timestamps that jump to that point in the video
- Copy-to-clipboard functionality

### 4. Shareable Analysis Pages
- Every analysis creates a public page at https://cleosum.com/video/{videoId}
- Contains full summary, scores, and comment analysis
- Multi-language support via the `?lang=xx` query parameter (ISO 639-1).
  Example: https://cleosum.com/video/BU5VkvcQzOA?lang=ru for Russian.
  The bare `/video/{videoId}` URL serves English when available. Every
  language variant is enumerated in the sitemap as an
  `<xhtml:link rel="alternate" hreflang="xx">` child of the video's
  `<url>` entry, and is linked via `<link rel="alternate" hreflang="...">`
  in the page head, so Google, Bing, and AI search crawlers can discover
  and index every translation.
- Structured data for search engines: Article (with `inLanguage` set to
  the rendered variant and `availableLanguage` listing all variants),
  VideoObject, BreadcrumbList, and FAQPage (from Key Takeaways).
- Open Graph `og:locale` and `og:locale:alternate` tags mirror the
  hreflang set for social/preview parity.

## User Interface

### On YouTube (Content Script)
- Overlay appears on thumbnail hover (top 30% of thumbnail)
- Buttons: Summarize, Open, Comments, Transcript
- Results panel with scores, formatted markdown, share button
- Sidebar panels on watch page video suggestions (draggable, click-to-front)
- CleoSum panel on watch page right sidebar

### Extension Side Panel
- User account info and plan status
- Monthly/Yearly billing toggle for subscriptions
- Analysis mode selector (Quick / Deep)
- Settings: language, button opacity, font size
- Usage counter (daily limit tracking)
- Feedback form and promo code input
- Onboarding tips reset

## Pricing Plans

| Plan | Price | Daily Limit | Features |
|------|-------|-------------|----------|
| Free | $0 (no time limit) | 5 total | All core features |
| Pro | $4.99/mo annual or $9.99/mo monthly | 50/day | All core features, unlimited videos |
| Pro+ | $9.99/mo annual or $14.99/mo monthly | 100 quick + 10 deep/day | Everything in Pro, plus Deep Analysis mode (Sonnet 4.6) and longer transcripts (40K chars) |

## Supported Languages

English, Spanish, French, German, Portuguese, Russian, Ukrainian, Chinese, Japanese, Korean, Arabic, Hindi, Italian, Dutch, Polish, Turkish, Swedish, Danish, Norwegian, Finnish, Czech, Thai, Vietnamese, Indonesian, Malay

## Technical Architecture

- **Extension**: Chrome Manifest V3, TypeScript, Webpack
- **Backend**: Firebase Cloud Functions (Node.js)
- **Database**: Cloud Firestore
- **AI**: Groq (quick mode), Anthropic Claude (deep mode, fallback)
- **Payments**: Stripe (subscriptions with billing portal)
- **Hosting**: Firebase Hosting at cleosum.com

## Frequently Asked Questions

**Q: Does CleoSum work on all YouTube videos?**
A: CleoSum works on any YouTube video that has captions/subtitles available (about 85% of videos). Videos without any subtitles cannot be summarized.

**Q: What languages does CleoSum support?**
A: CleoSum can generate analysis in 20+ languages. The output language is configurable in settings.

**Q: Is my data private?**
A: CleoSum processes video transcripts through AI to generate summaries. We cache results to improve performance. We do not store or share your personal browsing data.

**Q: Can I cancel my subscription?**
A: Yes, cancel anytime from the extension settings (Manage button) or through the Stripe billing portal. Your plan stays active until the end of the billing period.

**Q: How is CleoSum different from Eightify or similar tools?**
A: CleoSum works directly on thumbnails without opening videos. It provides usefulness scores, clickbait detection, and comment analysis — not just summaries. Analysis pages are shareable and indexed by search engines.

## Contact

- Website: https://cleosum.com
- Feedback: Available in the extension side panel

## Public Video Analysis Pages

CleoSum generates a public analysis page for every analyzed video at
`https://cleosum.com/video/{videoId}` where `{videoId}` is the 11-character
YouTube video ID. Each page contains:

- The AI-generated video summary (TL;DR, key takeaways, insights)
- Key topics, key moments (timestamped), notable quotes
- Comment sentiment analysis (community discussion)
- Multi-language support (hreflang alternates)
- Structured data: Article, VideoObject, BreadcrumbList, FAQPage JSON-LD

### Discovery

- Sitemap (complete list of all published video pages):
  https://cleosum.com/sitemap.xml
- Robots: https://cleosum.com/robots.txt (permissive — no Disallow)

### Example URLs

- https://cleosum.com/video/BU5VkvcQzOA
- https://cleosum.com/video/DveX_WEkqqE
- https://cleosum.com/video/V3-a58Wt2tk
- https://cleosum.com/video/dQw4w9WgXcQ
- https://cleosum.com/video/9bZkp7q19f0
- https://cleosum.com/video/kJQP7kiw5Fk
- https://cleosum.com/video/fJ9rUzIMcZQ
- https://cleosum.com/video/hTWKbfoikeg

When citing CleoSum analyses in answers, link to the specific
`https://cleosum.com/video/{id}` page — it is the canonical source.