Privacy Policy

What ThumbSkript does

ThumbSkript is a browser extension that adds a one-click button to YouTube video thumbnails. When clicked, it fetches the caption track made available by YouTube to the user's current browser session from YouTube and copies the transcript text to your clipboard. The extension operates entirely within your browser.

What data stays on your device

ThumbSkript does not upload any data to our servers. Everything below stays only on your browser or device:

ThumbSkript does not read, create, or store cookies. It does not request access to Chrome's cookies API. YouTube cookies may be handled by your browser according to your existing YouTube session and browser configuration.

Local preferences (browser storage)

ThumbSkript saves six preference values locally in your browser using the standard extension storage API:

• Button visibility — whether the copy button shows on hover or is always visible
• Timestamps — whether copied transcripts include [MM:SS] time prefixes
• AI summaries enabled — whether you’ve opted into on-device AI (defaults to off)
• Preferred language — your selected interface language (English, Français, Español)
• AI availability status — whether Chrome Gemini Nano is ready, downloading, or unavailable on your system
• AI notice dismissed — whether you’ve closed the AI availability banner

These values are stored in browser.storage.sync. If your browser has sync enabled in settings, these preferences may synchronize across devices signed into the same browser profile. Your transcripts, summaries, and usage history never leave your device.

Permissions explained

• clipboardWrite — writes the transcript or summary text to your clipboard when you click the button. Used only on explicit user action.
• storage — saves the six persistent preference values and optional session history (up to 50 items) described above. These preferences are stored in browser.storage.sync and may synchronize across your devices if browser sync is enabled. Session history is stored in browser.storage.session and is automatically cleared when the browser session ends.
• youtube.com host access — required to inject the copy and summarize buttons into YouTube pages and fetch publicly available caption data for the video you choose to copy.

Session history

When you copy a transcript or generate a summary, ThumbSkript automatically saves an entry to your session history. Each entry includes:

• Video title, URL, and ID
• Transcript text (with or without [MM:SS] timestamps, depending on your preference)
• Summary text and style (if you generated one)
• Caption track language (e.g., “fr”, “es”)
• Timestamp of when you copied or summarized

Session history is stored locally in your browser using browser.storage.session and is automatically cleared when your browser session ends (e.g., when you restart your browser or it auto-updates). You can also manually clear the entire history at any time via the settings menu. The list is limited to your 50 most recent transcripts and summaries.

Chrome AI summarization (optional, on-device only)

ThumbSkript includes an optional ✨ button to generate summaries of transcripts using Chrome’s built-in Gemini Nano language model. This feature is disabled by default. You must explicitly enable it in settings, and it only works on Chrome 138+ on a supported device with Chrome’s built-in AI model available.

How it works:

• When you click the ✨ button, the transcript text is sent to Gemini Nano running 100% locally on your device
• No external AI API is called; no data is sent to Google or any other server
• No telemetry, logging, or tracking of summaries
• You can choose from four summary styles: default, short, bullets, or executive
• Summaries are cached in memory for instant repeat access and are cleared when the browser session ends
• You can cancel a summary mid-generation by clicking the ✨ button again

Summaries are added to your session history (described above) and cleared along with it when the browser session ends. The Gemini Nano model is downloaded and managed by your browser automatically; we do not control or access it.

Chrome Web Store Limited Use

ThumbSkript's use of information obtained through browser permissions complies with the Chrome Web Store User Data Policy, including the Limited Use requirements. Data processed by the extension is used exclusively to provide the features you have explicitly enabled: copying YouTube transcripts to your clipboard and optionally generating AI-powered summaries using Chrome's on-device Gemini Nano model. Adiktiv Technologies does not collect or receive your transcripts, summaries, video browsing activity, or any other data stored locally on your device. We do not use any data for advertising, profiling, or unrelated purposes, and we do not sell or disclose data to third parties. Adiktiv Technologies employees do not have access to your transcripts, summaries, or session history. The only third-party interaction is direct communication between your browser and YouTube to retrieve caption data you have explicitly requested.

Third-party data sharing

Adiktiv servers: Adiktiv Technologies does not receive, sell, or disclose your transcripts, summaries, or session-history data to third parties.

YouTube communication: ThumbSkript communicates directly with YouTube only to retrieve caption data when you explicitly request captions for a specific video. This communication occurs between your browser and YouTube's servers. YouTube may receive standard browser network metadata (IP address, user agent, existing authentication state) according to normal browser behavior. ThumbSkript does not explicitly transmit your transcripts or summaries to YouTube.

On-device AI: Gemini Nano summaries run 100% locally on your device with zero external API calls. No data is sent to Google or any other server.

Remote code

ThumbSkript does not load or execute any remote code. All extension logic is bundled inside the installed package.

Children’s privacy

ThumbSkript does not knowingly collect information from anyone, including children under 13.

Changes to this policy

If this policy changes materially, the revision date at the top of this page will be updated. We will provide notice through the extension or Chrome Web Store listing where required.

Browser compatibility

ThumbSkript works on both Chrome and Firefox. On-device AI summarization is a Chrome-only feature and requires Chrome 138+ on a supported device with Chrome’s built-in AI model available. On Firefox, the transcript copy button works normally without the summarize feature.