In Star-Trek, the Prime Directive indicates that first contact with another species should not be done before they achieve warp capability. Why being able to travel faster than light would be a good sign that the species is ready for first contact is never explained.
Francis Carsac, in Ceux de Nulle Part, offers another criteria, dubbed Steel Law (Loi d’Acier), stating that first contact should never be attempted with any species that still knows any kind of local wars. That makes a bit more sense than the Star Trek criterion: an outsider with superior technology could otherwise easily be drawn to choose sides, a question that Carsac will later deal with extensively in Ce Monde est Notre.
However, if you think about it, the best criterion for first contact is probably the ability to communicate with a totally alien intelligence. Artificial Intelligence would be a good demonstration of that capability.
Someone Else's Problem 