Before you install any AI tool in your browser, it is worth asking a plain question: where does your data actually go? Most AI tools work by shipping whatever you give them to a server, and a browser extension can, in theory, watch a lot of what you do. Lensia is a Chrome extension built the other way around. Its main surface is a sidebar chat you keep open beside your work, and a floating panel you pull up for quick answers, and both are designed to send as little as possible off your device. This post walks through what a browser AI can and cannot see, where your data goes, and the settings that keep your studying private. Install Lensia free once you know how it handles your information.
What a browser AI can see, and what Lensia chooses not to
A Chrome extension runs inside your browser, so the honest answer is that it *could* read a lot. What matters is what it actually does with that access. Lensia only acts when you ask it to. Nothing gets read or sent when you are just browsing; the AI is called when you send a message in the sidebar or capture something with the panel, and not before.
When you do capture a question with the floating panel, the text is read off your screenshot on your own computer first. If that reading is clean, only the extracted text goes to the AI, and the image itself never leaves your device. Lensia only falls back to sending the actual picture when the text is too messy to read reliably (handwriting, a blurry PDF, a diagram with labels baked in). So in the common case, a screenshot of your exam review never travels anywhere. For the full walkthrough of that pipeline, read how Lensia works.
Where your data goes when you send a message
The sidebar is where most studying happens, and it is worth knowing what leaves your machine when you use it. When you send a message, Lensia forwards your question (and any text or image you attached) to the AI model you picked, gets the answer back, and shows it in the chat. Your conversation history and bookmarks live so you can return to them, but the point of the on-device text reading is that the raw screenshots behind them usually stay with you.
You also control which model handles your question with the model picker at the top of the chat, and if you would rather not think about it, Lensia Max picks a fitting model for each question on its own and takes 15 percent off the cost. Either way, you are sending a question to answer, not handing over a running feed of your screen.
Stealth Mode: keeping the panel off other people's screens
There is a difference between data privacy and simple visual privacy, and Lensia handles them with two separate features. The first is Stealth Mode, and it is on every plan.
Stealth Mode is about who can *see* the panel. Press Ctrl+Shift+E and the Lensia panel disappears completely, with no on-screen traces, badges, or flags left behind. Press it again to bring it back. That covers the visual threats: someone glancing over your shoulder in a library, or a webcam pointed at your screen seeing a clean page instead of an AI panel. It is a display setting, not a data setting; it changes what is on your screen, not where your information goes.
Privacy Guard: hiding the signals platforms look for
The second feature is Privacy Guard, and it is a Pro-only tool that handles a completely different problem. Some quiz platforms run scripts that watch for behavior, like whether your browser tab is active, whether you switched away, or whether known study extensions are installed.
Privacy Guard works at the browser level to hide those signals: it masks the tab-switch and focus changes those scripts look for, and it blocks scripts that probe for installed study tools. This is not about who can see your screen (that is Stealth Mode's job). It is about the detection scripts running on the page itself. The two features solve different problems, so keep them straight: Stealth Mode is for eyes and cameras, Privacy Guard is for platform scripts.
A couple of honest limits. Lensia is a Chrome desktop extension, so it does not run inside separate locked-down exam applications like Respondus LockDown Browser, which switch off Chrome extensions entirely. And no setting turns an AI tool into a license to cheat: Lensia is a study aid for learning material and checking your own work, and using it during a graded assessment where AI is restricted is academic dishonesty.
Practical privacy habits for any AI tool
The tool is only part of staying private. A few habits help no matter what you use:
- Sign in, do not paste keys around. Lensia uses Google sign-in only, so there is no key or token sitting in your notes or email to leak. Sign in once to activate and you are set.
- Capture tight. Draw your capture box around just the question, not your whole screen, so you are never sending more than you meant to.
- Know your two privacy switches.
Ctrl+Shift+Efor Stealth Mode when people are around; Privacy Guard on Pro when a platform is watching for behavior. - Read the tool's actual policy, not the marketing. Any tool that cannot tell you where your data goes is a tool to skip.
For a broader look at choosing a study tool that respects all of this, read the best AI tool for college students guide and the AI homework helper complete guide.
Study privately, starting today
You should not have to trade your privacy for a little help understanding a problem. Lensia keeps your screenshots on your device in the common case, only acts when you ask, and gives you two clear switches for the moments that call for them. Install Lensia from the Chrome Web Store, sign in with Google, and study with an AI that is built to keep your information yours.