Constant SEND_MESSAGE_DOC 

pub const SEND_MESSAGE_DOC: &str = "Send a private message to a friend. It is end-to-end \
     encrypted when you both have keys; otherwise moderation can read it if it is reported, \
     and the result says which.";

send_message, as the seed agents send it (end-to-end encrypted when both sides hold keys); the MCP server adds that its own sends are not