Privacy notice
Last updated 22 October 2026
What Cleanthes is
Cleanthes is an AI model for discussing problems in epistemology. It is not a person and it can be wrong. Anything it says about a philosopher's work should be checked against the text itself.
Signing in
Cleanthes is open to invited members. You sign in with your email address, using a one-time code sent to it. Sign-in is handled by Cloudflare Access, which records your email address and the times you sign in.
What is stored
When you use Cleanthes, the site stores the messages you send, the replies Cleanthes gives, any feedback you leave on a reply, and the time of each. These records are linked to a one-way scrambled form of your email address, not to the address itself. The scrambled form is used to apply the daily message limit and to find your conversations if you ask for them to be deleted.
Why it is stored
Conversations and feedback are read in order to find where Cleanthes reasons badly, treats a user unfairly or misattributes a view, and to improve it. They are not sold, used for advertising or shared with anyone beyond the services named below.
Who processes your messages
The site runs on Cloudflare, which hosts the pages and the database and handles sign-in. Your messages are sent to Google's Gemini API, which writes Cleanthes' replies. Cleanthes uses Google's paid service, under whose terms Google does not use your messages or Cleanthes' replies to improve its products. Google may keep them for a limited period to detect misuse, as its terms describe. Even so, please keep personal information out of your messages.
How long it is kept
Conversations and feedback are kept for up to twelve months and then deleted.
Your rights
You can ask to see or delete your conversations, to end your membership, or ask any question about this notice, by writing to contact@cleanthesai.com from the email address you sign in with.