Agent Dog (codename Agent D) is a O.W.C.A. agent. Little is known about him, such as his first name and main nemesis.
Agent D is a light brown dog with a black nose, dark brownish ears, sharp white teeth, a short tail, and an even lighter brown stomach. He is usually seen wearing a dark tan fedora with a reddish-brown band and a hat like Perry’s in other appearances.
his first name is unknown, not much is shown of him but he was seen in "Traffic Cam Caper". He was injured, along with Agent O, by Dennis the Bunny, the rogue agent, and had his right arm/paw in a sling ("No More Bunny Business"). He was also helping Carl with a drawing of Dennis.
Agent D also appeared in It’s about time sitting in the crowd with his nemesis at the Dr. Feallbetter show but I turned out to be a trap The agents starts fighting once they're freed.
He made a brief cameo appearance in Phineas and Ferb Christmas Vacation at the O.W.C.A Christmas Party. He returns in episode “Robot Rodeo” He was sent out to the L.O.V.E.M.U.F.F.I.N. completion and Perry free them and destroy the inators and fight with their nemesis. He appears again in "Rollercoaster: The Musical!" Signing with other agents at the end of the episode.
He reappears in “Phineas and Ferb Across the 2nd Dimension” the first Phineas and Ferb TV Movie He was seen to ambush a group of Normbots with other agents they were however captured and saved by Perry who was also saved by Phineas and Ferb and used her inventions to defeat the invasion of normbots. Agent D makes a various cameo in Agent Doof" and returns in Backyard Hodge Podge" Singing with other agents including Agent T, Agent Croddicale and more. But because it is animals it is really bad.
She made cameo appearance (None speaking) in video games Robot Riot, Agent P Strikes back and the Return of the Platypus. Robot Riot he becomes a playable defense player. In Agent P Strikes back he is a Captured agent and to find him in Level 2 first one he unlocks the doors. In Return of the Platypus in Level 2 to unlock him he opens a door and can teleport to help you in the final part of Level 2.
Note: He’s Fedora changes through his appearances
In different appearances, Agent D is seen wearing different fedoras.
In many appearances, Agent D is seen near Agent O.
Agent D appears in the online game Robot Riot! as a playable character.
According to his secret file, he specializes in tracking, has instinctive chasing skills, loves group sing-alongs, occasionally scratches behind ears, and pants in hot weather. (Where's My Perry?)
Agent D sitting in a Chair in his first apperence
Agent D on top left hand corner signing with Agent Pinky, Kangaroo, Peter the Panda, Frog