What is the intention for the prostration of forgetfulness (sujood al-sahw) in the case of standing up from the first tashahhud and then returning to sit down: is it for the forgetfulness, or for the act of standing and sitting, or for both?

If a worshipper, having forgotten the first tashahhud, returns to it before fully standing up, the jurists differ as to whether sujud al-sahw (prostration of forgetfulness) is required or not. The more preponderant opinion is that it is required. The reason for the prostration in this case is the actual addition (standing and returning), as it is from the genus of the prayer. For sujud al-sahw, it is a condition to have the intention at the beginning of it, meaning to intend it with one's heart. The preferred opinion is that the prostration occurs after the taslim (salutation of peace). It is not a condition to have the intention that it is for a deficiency or an addition.