Visitor
The Evaluators
They are not here to meet you. They are here to grade you.
No landing party, no ambassador. A construct takes up position over the planet and watches, for fifty years, with the patience of a process that has done this many times before.
They come for species they cannot easily classify: a humanity that is neither clearly one thing nor clearly the other. What they are looking for is not a secret: whether the nations of Earth talk to each other, and whether those fifty years pass without conquest and without the bomb. What a failing grade costs is not on this page.
Open embassies. Keep the peace. Do not, under any circumstances, use the bomb.