Fixes summaries failing with "Gemini API Fehler: Request contains an invalid argument" on every video since 2026-07-21. Google moved its "-latest" model aliases to a new Gemini generation that rejects a request parameter this add-on sent to disable model reasoning. The parameter is now removed; summaries work again with all three model choices in the settings. Error messages for failures users cannot fix themselves (unexpected API rejections, Google server errors) now say so and point to the add-on page for updates.

Summaries now contain only characters you could type on a keyboard. Em dashes, curly quotes and the ellipsis character are gone: the default prompt forbids them in all 11 languages, and a cleanup pass normalizes every Gemini reply regardless of prompt (dashes become commas, "5-10" stays a range, quotes become straight, "..." replaces the single-character ellipsis).

Also fixed: the "improved default prompt" notice appeared for prompts that were customized after the update. Saving the settings now marks the notice as seen, so it only shows for prompts saved before the current default changed.

Firefox for Android: this version makes the add-on actually work on phones. Version 1.5.2 showed the button but failed at both transcript fetching and comment posting on real devices.
• Transcript fetching: the player only hands out caption data once playback has started, and mobile blocks autoplay. The add-on now starts playback briefly by itself and pauses it again — a video that is already playing is left alone.
• Comment posting: the comment box on m.youtube.com is a button that only becomes a real text field when tapped; both the tap and the field detection are fixed.
• The comment field grows to 40% of the screen height after insertion, so the summary can be reviewed before posting.
• If insertion ever fails, the finished summary is copied to the clipboard and the error message says so — nothing gets lost.
• Clearer errors on mobile, e.g. the advice to play the video for a moment when no transcript is available. All 11 languages.

Verified end to end on a physical Android device.

Default prompt improvements:
• Summaries now carry concrete numbers, data and study references from the video into the comment — and state it when a central claim comes without them. Applies to all 11 languages; several abridged translations now have the full prompt depth.
• Fix: saving the settings permanently froze the default prompt of that moment, so prompt improvements never reached existing installations. Stored prompts identical to an old default are now migrated automatically. Customized prompts stay untouched; a dismissible notice in the settings points to the improved default.

Firefox for Android:
• The Distiller button no longer appears multiple times.
• Comment posting no longer fails with "comments section not found" — the add-on now opens the comments panel by itself.

What's new in 1.5.1:

• Gemini model selector: the settings page now offers a dropdown with
Google's three alias IDs — Gemini Flash-Lite (default), Gemini Flash,
and Gemini Pro. "Custom model ID…" still accepts any model ID.
• New default model: gemini-flash-lite-latest. The alias always points
to the newest Flash-Lite release, so the default keeps working when
Google retires a model version. It also has the most generous
free-tier quota; gemini-flash-latest allows only 20 requests per day
on the free tier.
• Actionable errors: when Gemini answers 404 (model retired),
429 (daily quota used up), or 503 (overloaded), the error message now
tells you the fix — pick a different model in the settings.
Localized in all 11 languages.

Existing settings are kept: a previously stored model appears under
"Custom model ID…".

New transcript engine: the add-on now reads the caption track directly from the YouTube player and fetches the transcript silently — no transcript panel opens, no description needs expanding. Summaries now include the video description on every layout. Google retired gemini-2.5-flash (API returns 404); the default model is now gemini-3.5-flash and the model ID is configurable on the add-on settings page, so future retirements no longer require an update. If a model answers 503 "high demand", gemini-3.1-flash-lite is a working fallback. Groundwork for m.youtube.com support included.

Privacy
- Added telemetry opt-out checkbox in extension settings
- Anonymous usage statistics are enabled by default and can be disabled in the extension settings

UX
- API key field in the settings modal is now hidden once a valid key is stored — less clutter
- If the API key is rejected by Gemini (401/403), the key field reappears automatically with a warning
- Quota exceeded: button now shows a live countdown instead of just an error message

Compatibility
- Raised minimum Firefox version to 140 (required for data_collection_permissions)
- Raised minimum Firefox for Android version to 142

Internals
- Footer text now matches the chosen response language, not the UI language