Cox's novel Dog Days, a satire of Washington, D.C. life for which she was reportedly paid $250,000, was published on January 6, 2006. The book received generally negative reviews. In The New York Times, Christopher Buckley described it as "brisk, smart" and "smutty." In the Times as well, Janet Maslin wrote that despite Cox's "satirical expertise," the novel is replete with "stock characters" and "manages to be doubly conventional: it follows both an old-fashioned love-betrayal-redemption arc and the newer, bitchier nanny-Prada chick-lit motif." Writing in Slate.com, Toby Young found the novel "shallow." He continued,
On July 27, 2006, Cox was named the Washington editor of Time.com, where she also wrote The Ana Log.