Okay, so the password generation is deterministic, based on a single secret I need to remember right? So then there has to be metadata to list the site domain,

Okay, so the password generation is deterministic, based on a single secret I need to remember right? So then there has to be metadata to list the site domain, username, which generation of password, which characters are allowed or disallowed, length, KDF difficulty, etc? Where is that information stored? What I'm getting at is with a brain wallet I only need to remember my secret and know the algorithm used to generate the key. With this it seems like you need a database to store more information, and without it, it's difficult to get your passwords back.