A code is sent back, there were some minor bugs with their code but for a race with zero interactions with humans, it was still impressively accurate

“The Perseus Arm as you call it is a very hostile area of space, from what we’ve detected, radiation from the countless nebulas and forming stars has led to the entire system being uninhabitable. Our own world is the single only one we discovered capable of creating life. We barely imagined there would be any other races out there.”
“However, as trade is your subject, we have many things to deal in. We have no need for raw materials like iron or hydrogen as farming such materials from asteroids, stars and nebulas is common practice in our civilisation, thus, we have an abundance of it. We instead have much more interest in hospitable worlds and the wood of your indigenous ‘trees’ as you call them. Our world relies on large fungi for oxygen production and does not have access to a recource as unique in values as wood. Such things are invaluable to us.”
“Contact us on your decision, cosmic brethren”