# properties.api_key.description
The new account's API key (mk_live_…) — store it now; it is only returned at registration. Sending stays blocked until the email is verified.

# properties.email.description
The normalized account email the verification link was sent to.

# properties.email_verified.description
Always false at registration — poll me() until it flips after the user clicks the link.

# properties.is_new.description
Always true — an existing email returns 409 account_exists (with no credentials) instead.