How can we know if a sutta was heard in the first person or not?

[Adutiya]

Who narrated Ananda's suttas?

According to tradition, Ananda is the main author of the Pali Canon’s Sutta Pitaka, in the sense that he was in charge of remembering the suttas and narrating them during the first council. From what I know, the suttas that he narrates start with “Thus have I heard” (Evaṃ me sutaṃ). I am reading MN52 and this sutta starts with the same form, but the sutta is about a conversation between Dasama of Aṭṭhakanāgara and Ananda. Therefore, this text must have been narrated by someone else during th…