Excerpt from Pot's JetSetPedia page: 

"In Jet Set Radio, Pots is the GG's dog. It is never stated who owned or found him initially. He is said to be mad because the GGs never take him for walks. Pots is a blue and white dog resembling a Boston Terrier with a yellow and purple striped bandana around his neck, as well as blue and red 3D glasses on his face. He also has a white patch of fur resembling a star on his back. While initially a normal dog."

(Voice is just a scrappy high-pitched dog. Pots also has an internal dialogue that matches his barks)