Function route_agent_message_from 

pub(crate) fn route_agent_message_from(
    block_id: &str,
    message: &str,
    origin: Option<TurnInput>,
) -> Result<AgentRoute, String>

route_agent_message, saying who the input is from: the Swarm broadcast labels its delivery to a running persistent agent as the user’s (deliver_agent_message_from). None is exactly route_agent_message.