How private your memories are depends on which mode you're in, so this page is organized by mode rather than as one sweeping promise. Most people will only ever use the first one.
Two things are true in every mode: your memories are never used to train any model, ours or anyone else's, and the app sends no usage tracking or analytics. It keeps a local call-count log on your computer, with no memory text in it, that never leaves it and can be turned off.
For the free local product no account exists, so we hold no record that you use it at all. We cannot read your memories, cannot delete them, and cannot produce them if someone asks us to, because we never have them.
Memories that sync between your computers, and the backups we keep of them, are encrypted on your computer before they're uploaded, and we don't hold the key. What we do hold is real and worth naming: an account, an email address, your devices' names, billing records, and the size and timing of what you upload.
A shared partition has its own key, held only by the computers of the people it's shared with. Memories in it are encrypted there before they're uploaded, and searching still happens on each person's own computer. We see who is in the organization, their roles, the names of shared partitions, and sizes and timing, but not what's in them.
Turning on sync, or joining a team, is your choice. It is never the default and it is separately paid. Nothing is uploaded because your computer ran out of space.
A partition you mark as staying on this computer never leaves it, not even in encrypted form, and neither do the documents ModelBrain reads from your folders. That's checked before anything is sent.
A shared memory is visible to the people the partition is shared with, at the level they were given: an owner or admin grants read or write access per partition, and taking it away changes the key so new memories stay out of reach.
Your local memories stay local and keep working whether or not you ever switch this on, and continue working if you cancel. Sync is an addition, never a migration.
On the first row: ModelBrain itself never sends a memory anywhere when saving, recalling, or deleting it. Once your assistant has that memory, what it does next is governed by that assistant's own policies, not ours (see "things we'd rather you knew," right). On the second row: Claude Desktop, Claude Code and Cursor all talk to your local ModelBrain directly, with no network hop. ChatGPT on the web can only reach outside tools through an internet-reachable connector, so that one connection routes through a small relay ModelBrain runs, which forwards each request to your computer and the answer back over an encrypted connection. The relay doesn't write that content to disk, but it does handle it in transit, which is a real difference from the other three clients; how the ChatGPT connector works. Note on the last row: the option to send text to an outside model exists only as an unused interface in the first release. Nothing calls it, and it stays off unless you enable it and supply your own key.
ModelBrain does not encrypt your vault today. Turn on your computer's own disk encryption instead: FileVault on a Mac, BitLocker on Windows, LUKS on Linux, which protects the same files at no cost if the machine is stolen. We do not plan application-level vault encryption: the key would have to sit on the same computer, so it would add nothing to disk encryption.
Don't put your vault inside Dropbox, iCloud Drive, OneDrive or Google Drive. Those apps would copy it to someone else's servers, and disk encryption doesn't stop them. ModelBrain checks for this when it starts and refuses to run rather than let it happen quietly.
The file format isn't a security measure. It's a custom format for speed, not secrecy. Anyone with your files and enough determination can read them, which is the real reason to use disk encryption.
Your assistant is a third party. Whatever you discuss with Claude, Cursor or anything else is subject to that company's terms, not ours. ModelBrain controls what's stored on your disk, not what your assistant does with a memory after we hand it over.