Attacks of Opportunity (3.5e Variant Rule)
From D&D Wiki
|This material is published under the OGL|
 Attacks of Opportunity
Using a skill that requires a standard action or full-round action generally provokes an attack of opportunity, and psychic skills are no different. However, character do have the option of using their psychic skills on the defensive, much like spellcasters may cast spells. The character makes a Concentration check with a DC of 15 or the DC of the psychic skill check, whichever is greater.
If the check succeeds, the psychic does not provoke an attack of opportunity for using that skill. If the Concentration check fails, then the psychic skill check automatically fails, although the character still suffers the strain damage. Characters with the Combat Concentration feat (page 201) get a +4 bonus on the Concentration check to use a psychic skill on the defensive.
Psychic skills that can be used as free or move actions do not provoke attacks of opportunity.