Screenshots, Window Titles, or On-Device: AI Time Tracking Privacy in 2026

Every time tracker on the market now leads with privacy. Rize puts "no screenshots or keylogging" on its pricing page. Memtime says nothing leaves your device. ActivityWatch is open-source and local. Coast says fully local. We say your screen text never leaves your Mac.

These claims are mostly all true, and they mean entirely different things.

"Private" has become a word that covers at least three incompatible architectures, and the differences matter far more than the marketing. Those same three architectures decide what a tool can see, which is covered from the accuracy side in our explainer on AI time tracking. This post is about how to tell them apart, including for our own product.

The only question that matters

Forget the copy. Ask this:

What does the software have permission to see, and where does it go?

Everything else follows. And on macOS, permissions make this unusually checkable, because the operating system will not let an app see your screen without you granting it.

The three architectures

1. Screen capture

What it sees: everything on your display. Pixels, and via OCR, all text: messages, medical portals, password fields caught mid-typing, another person's data in a shared call.

Permission tell: it must request Screen Recording. There is no way around this on macOS.

Who does this: continuous-recall tools like Coast and screenpipe, plus most employee-monitoring software.

The bargain: maximum fidelity. If you want to find something you saw on Tuesday, this is the only architecture that can. Local versions transmit nothing, which is a genuine guarantee.

The risk nobody states plainly: you have created a complete, indexed, searchable record of your entire digital life, sitting on one disk. Local means the blast radius is your machine, and the contents of that radius are total. A stolen laptop, a careless backup, a compelled device, or any software you have granted disk access to now reaches everything you have looked at, with the text already extracted for convenience.

Local is not the same as safe. It is a different failure mode, with lower probability and vastly higher severity.

2. Window metadata

What it sees: the name of the frontmost app, the title of the window, and the URL of the active browser tab. Names and titles. Not content.

Permission tell: Accessibility only. No Screen Recording request. If a tracker never asks for Screen Recording, it structurally cannot see your screen, whatever else you think of it.

Who does this: nearly every time tracker. Rize, RescueTime, Timely, Memtime, ActivityWatch, ManicTime.

The bargain: enough signal to be useful, a small fraction of the exposure.

The risk, stated honestly: window titles are not nothing. Offer Letter - Jane Doe.docx is a title. So is a Gmail subject line, and a URL with a document name in it. Anyone claiming metadata is inherently harmless is glossing. The right question is what the tool does with those titles before they leave.

3. On-device processing

What it sees: same as whichever of the above it uses. The difference is where the interpretation happens.

Who does this: Memtime, ActivityWatch, Coast, and Cronus for categorization.

The bargain: nothing leaves. Absolutely the strongest guarantee available.

The cost, which is real and rarely acknowledged: interpretation requires a model, and a model good enough to judge whether docs.stripe.com/webhooks served what you were trying to do this week is either a large model or a small one trained for this one job. A large general model running all day costs you RAM and battery, and an off-the-shelf small one is meaningfully worse at exactly this judgment.

This is why most fully-local trackers stop at recording. They will tell you what happened with perfect privacy. They will not tell you what it meant.

Where Cronus sits, precisely

We would rather write this down than have you infer it.

Cronus reads your screen's text. It asks for Screen Recording, because macOS puts window titles and on-screen text behind that permission. It reads the text of the active window and never saves or uploads an image of it.

A model on your Mac categorizes it. A small model trained for this job runs on the Apple GPU and picks the category. The screen text never leaves your Mac.

Metadata syncs to our servers: app names, window titles, URLs and the category each landed in. That is what lets the iPhone app show the same day. Window titles are the part of this worth weighing, for the reason above.

Cloud categorization is an opt-in setting. It is about 3x faster. With it on, screen text is sent to our servers, with passwords and keys stripped on your Mac first.

We are GDPR compliant. You can pause tracking whenever you want and revoke either permission at any time.

Full details are in our privacy policy.

So the trade with Cronus is: window titles and URLs leave your machine, the text on your screen does not, and a model on your Mac tells you what your time meant. If any metadata leaving is disqualifying for you, that is a coherent position and you should run ActivityWatch. We would rather you did that than felt misled.

How to audit any tracker in five minutes

This works on any tool, including ours.

1. Check System Settings → Privacy & Security → Screen Recording. If the tracker is listed, it can read your screen, and the next question is where that content goes. This is the single highest-value check and it takes ten seconds.

2. Check Accessibility in the same place. Nearly every tracker will be there. That is expected and is how automatic tracking works at all.

3. Search their privacy policy for "window title." A tool that transmits titles should say so. Vagueness here is the tell.

4. Ask what happens to sensitive strings. Is there redaction before transmission, or is the raw title sent? Most policies do not address this. It is the most important unaddressed question in the category.

5. Watch the network, if you care enough. Little Snitch or similar will show you what a "local-first" app actually talks to. Some are less local than the landing page implies.

Comparison

The point

There is no privacy ranking here, only a set of trades, and the honest version of the choice is:

• Total recall, total local, total exposure if the disk is ever reached. Screen recorders.
• Total local, no interpretation. Memtime, ActivityWatch.
• Screen text interpreted on your Mac, metadata synced. Cronus.
• Metadata, interpreted, with the redaction question unanswered. Most of the rest, and worth asking them about.

Pick the trade deliberately rather than by which landing page said "private" in the largest font.

If the trade we make sounds like the right one, Cronus is $8 a month after a 21-day trial.