GO:0097102:   endothelial tip cell fate specification
The process involved in the specification of identity of an endothelial tip cell. Once specification has taken place, a cell will be committed to differentiate down a specific pathway if left in its normal environment. An endothelial tip cell is a specialized endothelial cell localized to the leading edge of an angiogenic sprout that senses extracellular signals and guides the directed growth of blood vessels.