Firefox for Android Adds Shake-to-Summarize AI Feature

Mozilla has introduced a clever new AI-powered feature in Firefox 152 for Android: shake your phone, and the browser will generate a concise summary of whatever page you are reading. Dubbed “Page Summary,” the feature taps into Mozilla’s cloud-based AI infrastructure to deliver quick, digestible overviews of web content — no copy-pasting or switching apps required.

The feature is rolling out gradually, so users who update to Firefox 152 may not see it immediately. Once live, Page Summary is enabled by default, offering two ways to trigger it: either give the phone a shake, or tap the “Summarize page” button that appears in the browser interface. A prompt then pops up with the AI-generated summary.

Under the hood, Firefox relies on Mistral Small 3.1, a lightweight yet capable large language model from the French AI startup Mistral. The feature can handle pages up to 5,000 words in length and supports a range of content types, including news articles, how-to guides, product reviews, recipes, research papers, and opinion pieces.

Users who prefer not to use the feature can toggle it off — Firefox provides separate switches in the settings menu for “Summarize page” and “Summarize on shake,” giving people granular control over when and how the AI kicks in.

For now, the Page Summary feature is limited to English-language web pages, though Mozilla is making it available to users worldwide. Very long pages or pages with unsupported content may not display the summary option at all.

The move marks another step in Mozilla’s cautious but steady embrace of on-device-adjacent AI — keeping the heavy lifting in the cloud while baking AI convenience directly into the browsing experience. With competitors like Arc, Edge, and Chrome all racing to integrate AI tooling, Firefox’s shake-to-summarize gesture is a distinctly playful take on an increasingly crowded feature set.