As prevenom, except your weapon gains the poison coating as long as it remains in your grip.
If you have a claw attack (either from an actual natural weapon or from an effect such as claws of the beast), you can use this power to produce a mild venom that coats one of your claws. On your next successful melee attack, the venom deals 2 points of Constitution damage. A target struck by the poison can make a Fortitude save (DC 10 + ½ your manifester level + your key ability modifier) to negate the damage.
For every 6 additional power points you spend, this power's Constitution damage increases by 2 points.