Cairn doesn't replace your AI. It gives every AI you use the same memory.
One plain-text vault on your machine — it captures what you actually worked through (the decisions, the dead ends, the reasons why), local-first and append-only, built to outlast the chat it was written in.
The vault is one file on your machine — ~/.cairn/cairn.db — and it stays there. No cloud, no accounts, no telemetry, no one peeking over your shoulder. Your memory isn't a product. We think you should own it.
Plain text in open formats, append-only by law — the database itself refuses edits. Notes are voided, never deleted; the record can be corrected but never quietly rewritten. No link rot, no lock-in, no expiry date. What you learned outlasts the tool you learned it in.
Every note is a marker for the next session on the trail — future you, or your next model or agent. Cairn keeps the path, not just the answers: the decisions, the dead ends, and the reasons why. The path is the retrieval.
Every session ends. Chats compress, context rolls over, and the why falls through the cracks. Most AI remembers conclusions. Cairn remembers how you reached them — the decisions and dead ends stacked as plain text you own, on your machine and nowhere else, outlasting the conversation that made them. Every note is a marker the next session can follow: future you, or your next model or agent. Nothing disappears.
CAIRN REMEMBERS · SEALED MMXXVI
Model-agnostic by construction. Two rival vendors' models have already shared a single vault, live — one wrote, the other remembered.
Any MCP-speaking agent connects and gets the full memory toolkit — orient, note, fetch, search. Claude, Codex, whatever ships next.
The whole vault from a terminal: capture, query, the nightly sleep, the Garden. Pure Python — no daemon, no service, no account.
Ambient capture while you work — decisions and context land in the vault on their own, and the right memory surfaces at the right moment.
Every night, on your machine's clock — no server, no cron service in the cloud — the vault runs its sleep cycle:
The day's notes are embedded — findable by meaning, not just words.
Repeated episodes distill into knowledge — the way sleep turns a day into memory.
The graph rebuilds: topics find their names, every memory finds its place.
The vault checks itself — stale threads, blind spots, drift — and files what it finds for your morning.
Clone it, read it, run it, add your stone to the stack. Yours to read, run, and keep.