Mozilla has received plenty of flak for adding AI features to Firefox, like a chatbot in the sidebar, automatic alt text in PDFs, AI-powered tab group suggestions, and whatnot.It's been one thing after another, and while people might appreciate that these can be disabled, the sheer pace of the additions does make one wonder where it all ends.Their latest experiment in this space is the Smart Window, currently in beta and rolling out to users in the United States and Canada on Firefox 150 and newer. I got access recently, and here's what I found.📋The feature showcased here is of pre-production quality. Expect things to break.Good enough for daily useSmart Window is essentially a new type of Firefox window, sitting alongside Classic and Private, that comes with a built-in AI assistant. Unlike the existing chatbot sidebar, this one can actually see your open tabs, your browsing history, and the page you're currently on.You can ask it questions, get article summaries, compare things across tabs, and have it help you plan stuff, all without leaving the browser or reaching for a separate chat tool.We covered this back in November last year, when Mozilla announced what it was calling "AI Window" and opened a waitlist for early signups. At the time, it was mostly promises like building it in the open, keeping things opt-in, and giving users control over their data.Now, there's a working version that I tested on an Ubuntu 26.04 LTS system with Firefox 151.0.2 installed from Mozilla's official deb package. First, I had to log in with my Mozilla account (that had early beta access) and visit the Smart Window portal (linked earlier) to activate it on my browser.This is how I got access to Smart Window.Once through the portal, Firefox runs you through a quick setup with updated Terms of Use and a separate Privacy Policy to accept.Once in, you get to pick between three experiences. Fast uses Google's Gemini 2.5 Flash Lite, Flexible runs on Alibaba's Qwen3-235B-A22B-Instruct-2507, and Personal is powered by OpenAI's gpt-oss-120B.After that, you pick what Smart Window is allowed to learn from, with options like "Chats in Smart Window" and "Browsing activity across Firefox" ticked on by default.Unfortunately, I had accidentally gone with Personal, not seeing that it was powered by an OpenAI model, so I went into Settings > AI controls > Smart Window and switched over to Flexible.There's also a Custom option for connecting your own LLM endpoint, though Mozilla's documentation flags that local models may not always play nicely with Smart Window.With the model situation sorted, I asked the AI a question related to a hypothetical life-related occurrence. While it took some time processing the request, its replies were on point. It even suggested follow-up questions to ask that were very relevant.See below for a demo. 👇Summarizing content such as books, articles, and research papers is probably the most practical use of the Smart Window, in my opinion. I asked it to go through an article of mine on Bambu Lab being naughty with AGPLv3, and it gave me two options. One was to search for it on the default search engine, and the other was to ask the AI model directly.I chose the latter, and it spat out a detailed summary of the coverage, complete with some follow-up question suggestions. The output quality was good throughout, and I didn't spot any major issues.I also tried it out as a search tool, typing in "best food to pair with shawarma." That went fine, but the more interesting part was when I decided to push further.I asked whether the suggestions the search result (Gemini AI overview) was giving were rooted in authentic culinary traditions or were the result of misappropriation.It engaged with the question properly, which I wasn't expecting from an in-development browser feature. 🤓If you were wondering, all your chats are automatically stored locally on your device, and you can get to them from the Chats button in a Smart Window tab. It groups conversations by date, shows you what each one was about, and even links back to the page that triggered the search.Odd to see a chrome:// URL here (bottom-left).If you go into the settings for this mode, you will find that there are toggles to control whether Smart Window opens by default when Firefox starts, whether the assistant sidebar shows up automatically on each new tab, what the assistant learns from (chats, browsing activity, or both), and which AI model powers it.The 'AI controls' menu (left) and the 'Memories' menu (right).Below all that is the "Manage memories" section, where you control what the assistant learns from. You can view everything it has stored, delete individual memories you don't want sticking around, or turn the whole thing off entirely if you'd rather the assistant not learn from your activity at all.And before you panic that Firefox is becoming AI-only, there's a Classic/Smart Window switcher in the title bar that gives you a dropdown to jump between the two modes instantly. This way, your tabs stay put, nothing reloads, and going back to the classic browsing experience is just as fast as switching away from it.What now?Smart Window is shaping up well for a beta, and I wasn't expecting to say that. The AI integration is useful without being pushy, and Mozilla has mostly lived up to the opt-in commitments they made when they first announced this. It's expected to roll out to more users over time, though Mozilla hasn't shared a specific date yet, so if you're outside the US and Canada right now, keep an eye out on their socials.Meanwhile, if you are someone who'd rather keep AI features out of Firefox entirely (like me, on most days), Settings > AI Controls has a "Block AI enhancements" option that does exactly what it says.