When you have a problem like this, learn how to investigate what you can do with the class.
x = rand(10,1)*5;
y = rand(10,1)*5;
shape = alphaShape(x,y);
Methods for class alphaShape:
alphaShape alphaTriangulation boundaryFacets inShape numRegions plot volume
alphaSpectrum area criticalAlpha nearestNeighbor perimeter surfaceArea
methods tells you what methods have been provided. Here, do any of them sound interesting? I hope so.
edges = boundaryFacets(shape)
So a fairly boring alpha shape, since all but one of the points were on the perimeter.