A Firefox add-on that reads YouTube videos so you don't have to.
You open a video. Twelve minutes. You watch. You wait. The one insight you came for arrives at minute nine — buried under filler, recaps, and sponsor breaks.
YouTube Transcript Distiller fetches the full transcript and the video description, sends both to Google Gemini AI, and posts a clean summary directly into the YouTube comment field. One click. The important points, right where other viewers can see them.
- AI-powered summarization via Google Gemini (free API key required)
- Transcript plus video description — the summary draws on both, so context from the description flows in
- Silent transcript fetch — reads the caption track straight from the player, no panel opens, no scrolling
- Posts directly into the YouTube comment field — formatted and ready to publish
- Fully customizable prompt — change the instruction to anything you want
- Configurable Gemini model — pick Flash-Lite (default), Flash, or Pro from a dropdown, or enter any model ID manually
- 11 languages supported: Arabic, Chinese, English, French, German, Hindi, Japanese, Korean, Portuguese, Russian, Spanish
- UI adapts to your browser language automatically
- Quota countdown — if you hit the Gemini rate limit, the button shows a live countdown
- Privacy first — your API key stays in your browser, anonymous usage stats can be disabled in settings
The add-on can be installed from addons.mozilla.org.
- Download the latest
yt-transcript-distiller.xpifrom Releases - In Firefox:
about:config→ setxpinstall.signatures.requiredtofalse about:addons→ gear icon → Install Add-on from File → select the.xpi
- Get a free Gemini API key at aistudio.google.com/app/apikey
- Open any YouTube video
- Click the gear icon next to the Transcript Distiller button
- Enter your API key and save
- Click Transcript Distiller — the AI summary appears in the comment field
YouTube Video
│
▼
Transcript + description fetch
(player caption track → YouTube Internal API → DOM fallback)
│
▼
Google Gemini API (your API key, your quota)
│
▼
Formatted summary → YouTube comment field
The add-on never stores or transmits your transcript data anywhere other than directly to the Gemini API. The API key is stored locally in your browser via chrome.storage.sync.
- API key: stored locally, sent only to
generativelanguage.googleapis.com - Usage statistics: sent only on button click: add-on name, action and language settings. No personal data.
| Permission | Reason |
|---|---|
storage |
Saves API key, prompt and language preference locally |
clipboardWrite / clipboardRead |
Required for text injection into YouTube's comment field |
youtube.com/* |
Content script runs on YouTube pages only |
generativelanguage.googleapis.com/* |
Gemini API calls |
marsgasse.com/* |
Anonymous usage counter |
The prompt sent to Gemini is fully editable. Click the gear icon → edit the Prompt field. The default prompt instructs Gemini to produce a structured YouTube comment with bullet points, bold keywords, and blank lines between items — no raw Markdown, no HTML.
Click ↺ Reset to restore the default prompt at any time.
The Gemini Model dropdown (add-on settings page in about:addons) offers three alias IDs that Google keeps pointing at the newest release of each line:
gemini-flash-lite-latest— the default; fast, and its free-tier quota holds up in daily usegemini-flash-latest— stronger, but the free tier allows few requests per daygemini-pro-latest— effectively requires a paid plan
Custom model ID… accepts any model ID that supports generateContent from the Gemini model list. If a model answers with 404 (retired), 429 (daily quota used up), or 503 (overloaded), the error message says so — switching the model in the settings is the fix.
- Firefox 140+ (Desktop) / Firefox for Android 142+
- A free Google Gemini API key
- A YouTube video with subtitles/transcript available
- A Google account (required to post comments)
marsgasse.com — Just another Basement Lab
Michael Ruck · michael.ruck@marsgasse.com
MIT