Starting at 1st level, a master summoner can cast summon monster I as a spell-like ability a number of times per day equal to 5 + his Charisma modifier. The summoner can use this ability when his eidolon is summoned. Only one summon monster spell may be in effect while the eidolon is summoned. If the summoner's eidolon is not summoned, the number of creatures that can be summoned with this ability is only limited by its uses per day. This ability otherwise functions as the summoner's normal summon monster I ability. Other than these restrictions, there is no limit to how many summon monster or gate spells the summoner can have active at one time. This ability replaces the summoner's normal summon monster I ability and shield ally.
