Is Mage's Attendant legal in Standard, Modern, and Commander?

Mage's Attendant is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

What type of card is Mage's Attendant?

Mage's Attendant is a Creature — Cat Rogue. Its oracle text reads: "When this creature enters, create a 1/1 blue Wizard creature token with "{1}, Sacrifice this token: Counter target noncreature spell unless its controller pays {1}.""

Mage's Attendant

Creature — Cat Rogue

When this creature enters, create a 1/1 blue Wizard creature token with ", Sacrifice this token: Counter target noncreature spell unless its controller pays ."