Question: How do I add text to endpoint arrow in 3d?

I have an animated spacecurve with arrow:

restart:with(plots):

p4:=animate(arrow,[<cos(tend),sin(tend),0.9 tend>,<-cos(tend),-sin(tend),0>,color=red],tend=0..50,axes=boxed,frames=150);

I succeed in putting text at basis of arrow:

l3:=animate(textplot3d,[[cos(tend),sin(tend), 0.9 tend, 'basis'],color=black,align={BELOW},font=[TIMES,ROMAN,14]],tend=0..50,frames=150);

I like tot put text at the end of the arrow. This is my 'progress':

l4:=animate(textplot3d,[[<cos(tend),sin(tend),0.9 tend>,<-cos(tend),-sin(tend),0>,0.9 tend,'direction'],color=red,align={BELOW},font=[TIMES,ROMAN,14]],tend=0..50,frames=150);

display([p4,l3,l4]);

I receive:

Error:TEXT location must be numeric; received: [Vector(3, {(1) = 1., (2) = 0., (3) = 0.}), Vector(3, {(1) = -1., (2) = -0., (3) = 0.}), 0.]

Please help? What's wrong? I formulates three x,yz coordinates...