The material below is Open Game Content by a 3PP Source
Toppling Strike: If the soulknife’s mind blade has the Trip special feature, she may use it to make a single attack at her full base attack bonus as a standard action. If the attack hits, it deals damage normally and the soulknife can make a free trip attack (using her full base attack bonus) against the same foe. She does not provoke an attack of opportunity for this trip attempt. A soulknife must have the Weapon Special blade skill before selecting this blade skill.