President Donald Trump is so prone to outbursts that his aides have been forced to develop a coded language to warn one another about his volatile mood, according to his biographer.

A moment captured Tuesday between the 80-year-old president and his ever-present aide Natalie Harp appeared to offer a glimpse of the temper his aides are reportedly forced to navigate.

Reuters photographer Jonathan Ernst caught a scowling Trump just outside the Oval Office, his index finger raised beside his 35-year-old aide. Harp, clad in an all-white ensemble, smiled as she stood next to the sour-looking president, who appeared to be pointing toward Bill Pulte, the MAGA loyalist installed as director of the Federal Housing Finance Agency and chairman of Fannie Mae and Freddie Mac.

“He looked like he was completely downloading on her. She looked like she was conscious that there were cameras, and so she was sort of laughing and looking like she was frankly taking abuse,” host Joanna Coles said on the Inside Trump’s Head podcast.

“Everybody takes abuse,” Trump biographer Michael Wolff replied, explaining that the president’s aides learn that anyone will eventually find themselves in his line of fire.

Wolff, who has written four tell-alls about Trump and spent time in the White House during his first term, revealed that aides devised a secret phrase to tip one another off about what awaited them before seeing the president.

“People around Trump would say, ‘How’s the weather?,’” the author recounted, a discreet shorthand to find out, “What’s his mood?”

“This is a man who is wholly unfiltered. There are no restraints here... If he feels it, if he thinks it, he expresses it, and his powers of expression are... blunt force,” Wolff continued. “That’s it. You’re going to get it. It’s going to come at you.”

Wolff recalled seeing Trump give his longtime adviser Jason Miller a “horrendous” chewing-out, adding that Harp was bound to have endured the same treatment.

“The wrath has come on her, and it comes on her often,” Wolff said. “This was true about Hope Hicks, Margot Martin, all of these women around him.