Ms. Gnom dePlume's page

By RAW from UE, it is either a light exotic performance weapon that does lethal damage but without the reach, trip, and disarm of the whip, or "you can use a scorpion whip as a whip."

This last statement needs clarification. Many people are wielding scorpion whips as light lethal reach weapons with the trip and disarm properties, and that is not explicitly supported in the rulebooks.

If Handle Animal cannot be used as a free action out of turn, then AC's could not take opportunity attacks on monsters that they had not been commanded to attack.

Similarly, if "step up" were a trick, then it could also be used as a free action out of turn, assuming that the handler and the animal are in communication. So the animal expends its immediate action, the handler consumes a free action.

Core Rulebook, page 97, under Handle Animal, "Possible tricks (and their associated DCs) include, but are not necessarily limited to, the following." The usual list of tricks follow.

Core Rulebook, page 52, under Link, "A druid can handle her animal companion as a free action, or push it as a move action."

I am not a rules Nazi for Handle Animal, but I have seen many judges react negatively to very loose assumptions as to what is implied in a trick. Can a character use the "attack" trick to command a snake AC to bite without grabbing? How about as an opportunity attack?

With respect to RAW, I think the intent of the Handle Animal text is to allow players to give their AC's the feats under discussion here AND the requisite tricks to make them effective. I do not see a statement equivalent to the above regarding "custom magic items."

Handle Animal with a "step up" trick can occur as a free action, making the feat useful. Using it as a trick also allows the character the option at that juncture not to utilize the feat.

Core Rulebook, again page 97, under "Down", "An animal that doesn't know this trick continues to fight until it must flee (due to injury, a fear effect, or the like) or its opponent is defeated." Does an Int 1 snake constricting some delicious morsel know that defeated means dead?

Some judges, like me, would probably rule that way, but not all. I have seen many druids not train their animals with "down" and assume that their "attack/attack" tricks encompass all sorts of variations without using the DC 25 push as a move action.