YouTube Summary with Gemini: Open Source One-Click Summarizer

About

Watching a long YouTube video and want the gist first? YouTube Summary with Gemini adds one toolbar button: click it on any YouTube video and Gemini opens in a new tab with a summary prompt already filled in and sent — the video's title and link are added for you automatically.

That's the whole product. No dashboards, no accounts to create, no servers in the middle. You stay in your own Gemini session the entire time.

WHY YOU'LL LIKE IT
- One click: on any YouTube video, click the toolbar button and Gemini starts summarizing — title and link attached automatically.
- A green "ready" dot on the toolbar icon tells you at a glance when you're on a video the extension can summarize.
- Fully editable prompt: the default is a short "Summarize the video:" so Gemini picks a good structure, but you can rewrite it to analyze, critique, pull action items, or ask your own questions. Edit it any time on the options page.
- Never stuck: Gemini has no official prefill URL, so auto-fill types into Gemini's input directly. If Google changes that page, the extension falls back to a copy-to-clipboard toast with your prompt — it degrades, it never fails silently.
- Private by design: no analytics, no tracking, no ads, no data sent to the developer. The only thing transmitted is the prompt you send to your own Gemini session.
- Featherweight: vanilla HTML/CSS/JS, Manifest V3, no frameworks, no background polling.

HOW IT WORKS
On a YouTube video the extension reads the page URL and title only when you click. It builds your prompt (your instructions + the video's title and link), opens Gemini in a new tab, types the prompt into Gemini's input box, and sends it. Everything happens in your browser, in your signed-in Gemini session.

OPEN SOURCE (MIT)
YouTube Summary with Gemini is fully open source under the MIT license. Read the code, file an issue, or contribute:
https://github.com/wizdes/yt-gemini-summary

GETTING STARTED
1) Install and pin the extension (puzzle icon → pin) so the toolbar button is visible.
2) Sign in to Gemini in the same browser.
3) Open any YouTube video and click the button. That's it.

Tip: want a different prompt? Right-click the icon → Options.

https://yili.dev/projects/youtube_summary_with_gemini/