White House Deputy Chief of Staff Joe Hagin, the puppeteer pulling the strings on the U.S.-North Korea summit from behind the scenes, handles the delicate preparations by keeping details from President Donald Trump out of fear that he will tweet about them, according to a Monday CNN report.

Two unnamed officials told CNN that Hagin did the same thing when Chinese President Xi Jinping was planning to visit Mar-a-Lago last year.

Hagin reportedly often cites an incident when Trump’s transition team was in negotiations with Boeing about building a new Air Force One fleet, with the understanding that the talks would be kept quiet. Almost immediately when he was told, Trump tweeted about the particulars of the deal, prompting Hagin to warn “remember Boeing” as a catchall for keeping Trump out of the logistics.

White House press secretary Sarah Sanders said that she has never heard Hagin say that, telling CNN that “I’ve worked very closely with Joe and it’s just not how his mind thinks or the way that he operates.”

Three unnamed current and former White House officials told CNN that another Hagin catchphrase is “this would never happen in the Bush administration,” often served up with an eye roll for emphasis. Sanders did not dispute this comment, saying that it is natural for Hagin to compare the Trump administration with his most recent White House experience.

Hagan has reportedly worked for every Republican administration since Reagan, specializing in organizing summits, foreign trips, and other presidential logistics.