The cinematic, mission-critical, passkey-armoured, markdown-native, agent-agnostic cognitive persistence layer for the post-context-window era. It stores notes. In markdown. And it is going to change your f***ing life.6
you › Remember that I take my coffee 1:16 ⚙ bm_write(title: "Coffee preferences") ✓ saved main/coffee-preferences rev 3f9a1c2 · it is now a monument
I get a lot of ladies, but who has time to keep track of all those feelings and memories and shit? I use Cairn to track my ladies and impress them with how well I pay attention.
Tanner Vexley, Lover, Fighter, Note-taker
It’s kinda like a high school locker room, but with search.
Brayden Kolt, Regional Vibes Manager
My cat holds grudges. Now so do I, in a searchable format.
Linda Purrsworth, Cat liaison
My crypto thesis is 412 notes long and the core insight is “number go up.”
Bryce Hodlman, Chief Vibes Officer, MoonDAO (rug pending)
I keep notes on every meeting. Then I schedule a meeting to review the notes.
Gary Plimpton, Senior Associate Manager of Meetings
My name is Whey-Lon Isolate and I approve this memory system.
Whey-Lon Isolate, Legal name (since 2022)
*Fictional. Obviously.
As breathlessly covered in
Capabilities
Every feature below is real. Only the adjectives have been enhanced for theatrical release.
Format
Every memory is a markdown file with observations and [[links]]. Not a vector. Not a vibe. Not a “proprietary cognitive embedding”. A file you can read, edit and take with you. It will outlive three startups and at least one civilisation.
# Coffee preferences ## Observations - [preference] Takes coffee at 1:16 #ritual - [method] Pour over, every morning, no exceptions ## Relations - requires [[Burr Grinder]]
Recall
10,000×
more recall than a goldfish1
Hybrid search runs full-text BM25 and 1024-dimensional vector search, then fuses them with Reciprocal Rank Fusion: an algorithm with the word “fusion” in its name.
0
passwords stored. We counted twice.
Passkeys only. Your face, your finger, your security key. Ten single-use recovery codes at signup, for when the fingers go missing.
A remote MCP server behind OAuth 2.1 with PKCE (an acronym inside an acronym). claude.ai and Claude Code connect in about ninety seconds. Eight tools, all prefixed bm_, all business.
Receipts
Every write returns a receipt with the note, revision and time. No receipt, it didn’t happen. Like brunch.
saved main/coffee-preferences
rev 3f9a1c2 at 09:14Your [[links]] are the graph. Relations like relates_to and requires are typed, forward references wait patiently for their notes to exist, and the viewer shows backlinks. We did not build a graph database, and frankly that is the boldest thing we have ever done.
1
private SQLite database per vault
Each vault lives in its own Durable Object on Cloudflare’s edge. Your memories do not make eye contact with anyone else’s. Every write records who made it, which agent, and keeps the prior revision.
Freedom
1 click
to leave with everything
Download a zip of every note as markdown, links intact. Opens in Obsidian or Basic Memory. We’ll cry, but quietly.
Viewer
A web viewer with rendered notes, live wiki links, backlinks, search, and a feed of what your agents wrote recently. Agent-written text is rendered safely, because trust is earned.
Deployment
~$5
per month to self-host a heavy user5
One Cloudflare Worker. Runs on the edge. The edge of what? Of everything.
The Cairn Pipeline™
Our patented7 three-phase cognitive persistence architecture, explained with the gravity it deserves (and, underneath, what actually happens).
A thought is born. Your agent, sensing its importance, commits it to eternity.
What happens: your agent writes a markdown note with observations and relations over MCP, and gets a receipt.
The note is shattered into meaning and reforged as an index of terrifying precision.
What happens: the markdown is parsed into a full-text index, embeddings and relation rows. They’re rebuilt from the text, which stays the source of truth.
Weeks later, in a new chat, your agent remembers. You feel seen. Possibly too seen.
What happens: the agent searches, follows links a few hops out, and reads what it needs.
Total phases: 3. Total graph databases: 0. Total LLM calls on the server: also 0. The server is cheap and dumb; your agent is the clever one.
Testimonials
Every name, face and quote below is invented. The feelings are not.
I’ve outrun eleven exploding helicopters. Only one thing ever scared me: forgetting where I parked the twelfth. Cairn remembered. Cairn always remembers.
I told my agent my grandmother’s risotto recipe once. Once! Now it brings it up in every conversation. Magnifique. Also, a little much.
In orbit we had a checklist for everything. Cairn is that checklist, but with backlinks. I wept. In zero gravity your tears just sort of hang there. It’s a whole thing.
If a memory is stored in markdown and no agent reads it, does it persist? Yes. That is literally what “persist” means. Cairn opened my third eye and then gave it a permalink.
I REMEMBER EVERY SLICE. WHITE. RYE. THE SOURDOUGH OF ’24. CAIRN GAVE MY SUFFERING A PERMALINK. 10/10. WOULD POP AGAIN.
I don’t know what any of this is, but the young man said it would change my life and so far it has not. Lovely colours, though. One star off for the swearing.
We used to keep the company’s institutional knowledge in Gary. Gary retired. Now we keep it in Cairn, and Cairn has an export button. Gary did not have an export button.
On the mountain, you stack a stone to say “someone was here, and the path goes this way.” I didn’t expect a database to make me feel that. I also didn’t expect a database.
Recognition
Pricing
Choose the tier that matches your destiny. They all cost the same.
For individuals who remember things occasionally.
$0/ month
Free, forever, or until the heat death of the universe.
For professionals whose memories have memories.
$0/ month
Billed annually at $0. Save 0% vs. monthly!
For organisations with a Chief Remembering Officer.
$0/ seat
Contact sales. There is no sales. The void will answer, and the void is also free.
For civilisations, hive minds and at least one toaster.
$0/ light-year
Pricing adjusted for relativistic time dilation.
All four tiers are the same tier. Cairn is a personal project running on one person’s Cloudflare account, so it costs you nothing.5
FAQ
The questions are absurd. The answers are mostly true.
Statistically, yes. Practically, it gives your AI assistant a place to keep markdown notes between conversations, and a way to find them again. Whether that changes your life depends on how much you were repeating yourself before.
A memory server for AI assistants, running as a Cloudflare Worker. Your agent connects over MCP (with OAuth), and gets tools to write, read, edit, search, list and delete notes, and to follow the links between them. Notes use the same markdown format as Basic Memory: observations like - [preference] … and relations like - relates_to [[Other note]]. You sign in with a passkey, and there’s a web viewer for browsing what your agents have saved.
They stay warm in a SQLite database inside a Cloudflare Durable Object, one per vault. Search indexes (full-text and vectors) are built from your notes and can always be rebuilt from them. The markdown is the source of truth; nothing exists only in an index.
Cairn doesn’t train anything, and there’s no language model on the server. To make semantic search work, note text is turned into embeddings with an open embedding model on Cloudflare Workers AI. Your clever agent does the thinking; the server just stores and finds.
Deeply. At signup you get ten single-use recovery codes: save them somewhere that isn’t Cairn. Adding a second passkey (say, your phone and your laptop) is the best insurance. There is no email reset, because there is no email.
Yes, and only a little. Settings → Download everything gives you a zip of every note as markdown, with [[links]] intact, ready for Obsidian or Basic Memory.
Anything that speaks remote MCP with OAuth. claude.ai and Claude Code are the tested path; the connect guide walks through both in about two minutes.
Cairn will remember which plane. Beyond that, frankly, you’re on your own.
The marketing is. The celebrities, companies, publications and awards are invented. The software is real, it works, and it’s built to be self-hosted on Cloudflare Workers.
In a world where context windows close…where every chat starts from nothing…one memory system dared to write it down.
Sign up with a passkey in about ten seconds. Connect your agent in about ninety. Tell it something once.