Privacy policy

Rule Ø ("Rule Zero") is a small hobby project run by Pjotr for himself and a few friends. This page says what it stores and why. Last updated 12 October 2026.

What is stored

• Your account: a username, a hashed password (never the password itself), an email address (only used to send you a password-reset link) and the date you joined. If you asked for an account, also the note you wrote and the network address the request came from.
• Sign-in with Google or Discord: only a stable ID, your display name and, for Google, your email address. These are shown to the owner when you ask for an account, and the ID is kept to recognise you next time. Nothing else from your Google or Discord account is read, and nothing is posted there.
• What you add: decks, your collection, matches you log, settings, your profile picture, and the short notes Tamiyo remembers about you. Each account's data is kept separate from the others.
• AI usage: how many AI calls you made, and the cost, so limits can be enforced.
• Cookies: one cookie that keeps you signed in. There is no advertising and no tracking.

The AI

When you chat with Tamiyo or run an AI analysis, the text of your question and the relevant cards are sent to Anthropic (the company behind Claude) to produce an answer. Don't type anything personal into the chat.

Where it lives, who sees it

Everything is stored on a home server in the Netherlands. The owner can technically see account data. It is not sold or shared, except for the AI processing above and the email the server sends to the owner when someone asks for an account.

Your choices

You can change your password and picture in the app. To see, correct or delete your account and everything in it, email [email protected]. If you signed in with Google or Discord, you can also remove Rule Ø from that service's connected apps at any time.

Rule Ø is unofficial Fan Content permitted under the Fan Content Policy. Not approved or endorsed by Wizards of the Coast. Portions of the materials used are property of Wizards of the Coast. ©Wizards of the Coast LLC.