The process in which a cell becomes capable of differentiating autonomously into a nematode vulval cell in an environment that is neutral with respect to the developmental pathway; upon specification, the cell fate can be reversed. In nematodes, the vulva is formed from ventral epidermal cells during larval stages to give rise to a fully formed adult vulva, which is the egg-laying organ of female and hermaphrodite nematodes.
vulval cell fate specification