The secret of the mage familiar was first discovered where mages used special spell-casting familiars to strengthen their spells.
The mage familiar is an archetype for familiars with a MP pool.
Echo (Su)
At 1st level, once per day, when delivering a touch spell, a mage familiar can apply the Extend Spell metamagic feat to the spell. A mage familiar can use this ability twice per day at 8th level, and three times per day at 13th level.
This ability replaces alertness.
Extra MP
At 1st level. a mage familiar receives the Extra MP feat as a bonus feat.
This ability replaces improved evasion.
Reverberate (Su)
At 7th level, once per day when delivering a touch spell, a mage familiar can apply either the Empower Spell metamagic feat to the spell or use the Heighten Spell metamagic feat to increase its spell level by 2. A mage familiar can use this ability twice per day at 11th level.
This ability replaces speak with animals of its kind and spell resistance.
Resonate (Su)
At 13th level, once per day when delivering a touch spell, a mage familiar can apply the Maximize Spell metamagic feat to the spell. A mage familiar can apply only one metamagic effect to a single casting of a spell using its echo, reverberate, or resonate abilities.
This ability replaces scry on familiar.