A family like mesh-mail's mail-credential-* names only the module and the secret's key at the desk, so the operator cannot tell which account is asked. An own secret (or a family) may now declare a one-line prompt in its manifest, with {member} filled by a family member's suffix; the module check refuses one that is not one line, over 120 characters, or holds another placeholder. desk_secret.go reads it from the controller's own catalogue and sends it to the desk as what, never from the call or the module's runtime; omitted when none is declared, so an old desk or module behaves as today.