SUMMON WITHER SKULL

This is what you posted:

/summon WitherSkull ~ ~2 ~{direction:[0.001,0.001,0.001]}

You forgot a space.

Won't Fix
see Searge's comment in MC-67918

(@StevenNL2000: That is a Jira bug, if you copy it, it doesn't copy the space properly if there is a line break)