Battlemagic Perception

Heroes of Battle (HB)Supplementals (3.5)
School
Divination
Casting Time
1 standard action
Components
V, S
Range
Personal
Target
The caster
Duration
10 minutes/level (D)
Saving Throw
None (harmless)
Spell Resistance
No (harmless)

You gain a perception of the forces of magic and can sense when magic is being manipulated by a spellcaster.

You gain a +5 competence bonus on Spellcraft checks made to identify a spell as it is being cast.

If you have at least 5 ranks in Spellcraft, you are also able to sense the use of any spell or spell-like ability within 100 feet, so long as you have line of effect to the caster.

With a Spellcraft check (DC 15 + spell level) you can even ascertain the spell being cast.
This determination happens quickly enough that you can attempt to counter the spell as a free action.

Counterspell attempts are otherwise handled normally, and you can counter the spell even if you do not have line of sight to the spellcaster.

If you counter a spell in this manner, the battlemagic perception spell ends immediately.