Chapter one

It answers because it was writing the whole time. The Memory Engine writes down every session you have with an AI, by itself, and saves it as dated notes in a folder on your own Mac. It hides your passwords before anything is sent, and it searches Arabic as well as it searches English. Nothing is uploaded, there is no account to make, and nothing about you is tracked.

You type nothing. The moment a session ends it gets written down, and every fifteen minutes it goes back over the chat histories of every assistant it reads, in case one of them crashed or you forgot to close it. Below you can watch one of those rounds, and the filter that hides your passwords before anything is sent. Both of them are live on this page.

What comes out of all that is not a database. It is ordinary notes in your own folders: one running log, a file for each person, a file for each project. Read every line it wrote, change it, delete it, or open the folder in a notes app like Obsidian. It is yours, and it is the part that stays when everything else is gone.

Every vendor shipped memory in 2026. Not one of them shipped a memory another assistant can read, and the vendors who ship two or three cannot read across their own. Pick a source. Then throw the switch.

These counts are from my own folder, taken on 2026-08-18. Cursor reads zero because it does not publish where it keeps its history, so an update to the app can move it; the health check tells you the day that happens rather than months later. Where an assistant announces the end of a session, that is used. Where it does not, the sweep finds the session anyway, which is why a crashed session and a sleeping laptop change nothing.

Seven weeks of it running, counted straight out of my own folder on 2026-08-18.

Where it loses. It looks for words, not for meanings. Ask it something using words that appear nowhere in your notes and it can come back empty, and three of the alternatives below do that part better. It is switched off here on purpose, behind a list of every question it failed to answer, and on my own folder that list is nearly empty. A fast wrong answer is worse than no answer, and that is the whole reason you can trust the numbers above.

what each way costs over three years

List prices read off the vendors' own pages on 2026-08-18. Every bar is drawn to the top of its range, because that is the tier a working professional actually lands on.

The last bar is the only one on this chart not drawn to scale, for the obvious reason. Every other figure is the published rate multiplied by thirty six months.

A page that only lists strengths is no use in a buying decision. These are the reasons to walk away, in the same words the kit's own documentation uses, which you can read before you pay.

1. You want a notes app with an AI button. This is machinery around an assistant, not an editor.
2. You only work on a phone or a tablet.
3. You want it finished this afternoon. On its first run it goes back over the conversations already on your Mac, and it builds up from there. The folder you start today is the one you will be searching in a year, and every week you wait is a week missing from it.
4. You will never look at the suggestions box. Anything it is not sure about stops and waits for you, on purpose. That costs you a few minutes a week, and it is exactly why you can trust everything else it wrote.
5. You need a shared folder for a team, a phone app, or cloud sync. This is one person, one Mac, and their own work.
6. You want it to cost nothing at all to run. Reading, searching and remembering are all on your Mac and free. Writing the summary is a request to your assistant: nothing on top of the subscription you already pay for, or around twenty cents on a busy day if you would rather it used its own key, under a daily limit you set.
7. You are happy losing the last two years of decisions and would rather keep explaining them from memory.