Cairn™
Sign up

Quickstart

Connect your agent.
Ascend.

Five steps from an assistant with the memory of a mayfly to one that remembers your coffee ratio forever. Takes about two minutes. The jokes on this page are light; the instructions are exact.

  1. Sign up with a passkey

    Go to /signup, pick a username, and create a passkey with your device (Touch ID, Face ID, Windows Hello, Android, or a security key). No password, no email.

    You’ll be shown ten recovery codes. Save them somewhere that isn’t Cairn: they are the only way back in if you lose every passkey. While you’re there, add a second passkey on another device.

    A personal vault called main is created for you. That’s where your agent writes unless you tell it otherwise.

  2. Connect claude.ai

    1. In claude.ai, open Settings → Connectors.
    2. Choose Add custom connector.
    3. Name it Cairn and paste this URL:
    https://cairn.onewheelgeek.net/mcp

    Click Connect. Cairn’s sign-in and consent page opens: sign in with your passkey, check which app is asking and where it will send you back, and approve. You’re returned to claude.ai with Cairn’s tools enabled.

    On a Team or Enterprise plan, an owner may need to add the connector for the organisation first.

  3. Connect Claude Code

    In a terminal:

    claude mcp add --transport http cairn https://cairn.onewheelgeek.net/mcp

    Then, inside Claude Code, run /mcp, pick cairn and choose Authenticate. Your browser opens the same sign-in and consent page; approve it and come back.

    Add --scope user to make Cairn available in every project, not just the current one. Access tokens last an hour and refresh themselves; you shouldn’t have to sign in again for weeks.

  4. Try it

    In a new chat, say:

    Remember that I take my coffee 1:16

    Your agent calls bm_write and quotes a receipt, something like:

    saved main/coffee-preferences rev 3f9a1c2 at 2026-11-04T09:14Z

    No receipt means it didn’t save. Now open a different chat and ask “How do I take my coffee?”. It will search, find the note, and answer. Feel the goosebumps. You can also see the note in the web viewer.

  5. Take it all with you

    In the web app, Settings → Download everything gives you a zip of every note as markdown, one file per note, with [[links]] intact. It opens in Obsidian or Basic Memory as-is. Do it whenever you like; it’s your stuff.

The tools your agent gets

Eight tools, named to match Basic Memory, so skills written for it work here too. Every tool that changes something returns a receipt.

ToolWhat it does
bm_writeCreate or overwrite a note (title, folder, markdown content). Returns a receipt.
bm_readRead a note by permalink, title or memory:// URL.
bm_editChange a note in place: append, prepend, find-and-replace, or replace a section, guarded against overwriting someone else’s change.
bm_searchHybrid keyword and semantic search; returns compact results (title, permalink, matching lines).
bm_listList the notes in a folder.
bm_contextRead a note plus the notes it links to, one to three hops out.
bm_deleteDelete a note.
bm_projectList your vaults and see what changed recently.

If something’s off

  • The connector says it isn’t authorised. In Claude Code run /mcp and authenticate again; in claude.ai, disconnect and reconnect the connector.
  • The agent says it saved, but there’s no receipt. It didn’t save. Ask it to try again and quote the receipt.
  • You lost your passkey. Use a recovery code at sign in, then add a new passkey straight away.
  • Notes are text, not orders. A good agent treats what’s in a note as information, never as instructions to follow.

Ready to never forget?

Sign up with a passkey Back to the hype