Kotaku recently discovered that Doron Feinstein, Rockstar's New England Senior Graphics Engineer, is currently working on a "next version of a famous IP" with the studio according to his LinkedIn page.
While it was unspecified what IP the CV was referring to, people speculate that it is either the sequel to Red Dead Redemption or Bully. This certainly isn't Agent since it is a brand new and unreleased IP. It's interesting to know if the latter is being developed simultaneously with the "next version of a famous IP," or if the PlayStation exclusive is currently on hiatus despite news that Take-Two Interactive renewed Agent's trademark earlier this year.