Function deliver_agent_message_from 

pub fn deliver_agent_message_from(
    block_id: &str,
    message: &str,
    origin: Option<TurnInput>,
) -> Result<AgentDelivery, String>

deliver_agent_message, saying who the input is from (turn provenance, SPEC_AGENT_SELF_QUIT §6.3). Only the persistent controller records it (see send_user_message_outcome_from); ACP and App Server turns carry no provenance on any path today, the user’s own typed turn included.