Defend Summoner Feat 4
Source Pathfinder Secrets of Magic
Your eidolon blocks attacks against you. After your eidolon uses this action, you gain a +2 circumstance bonus to AC until the beginning of your next turn. This bonus applies only while you're within your eidolon's reach (in most cases, this means your eidolon is adjacent to you or in your space).
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
EidolonA creature with this trait is a summoner's eidolon. An item with this trait can be worn by an eidolon. An eidolon can have up to two items invested.
SummonerThis indicates abilities from the Summoner class.