On Friday afternoon, the world’s richest person showed up at what sounds like one of the world’s most boring agencies to demand a list.

Elon Musk had arrived at the Office of Personnel Management, a mundane-sounding agency with vast power overseeing the federal civilian work force. During President Trump’s first term, the nation’s leader used the agency to enforce loyalty to his agenda. During his second term, it appears Mr. Musk may try to use the office to enforce loyalty to his own agenda.

Mr. Musk has stormed into Washington with a host of friends and paid employees, determined to leave his imprint quickly. Never before in modern times has someone so rich played such a hands-on role in American government, with Mr. Musk making himself omnipresent in Washington since flying there for Mr. Trump’s inauguration. His plane has not left.

On Mr. Trump’s first day, he empowered Mr. Musk by establishing the so-called Department of Government Efficiency, a cost-cutting effort that the tech billionaire is leading. Mr. Trump gave the group the authority to work on a plan to reduce the size of the federal work force, among other things.

Taking to Washington with his trademark single-mindedness and bravado, Mr. Musk is reprising the tactics he deployed at Twitter, which he bought in 2022. He has brought to bear the full weight of his Silicon Valley network, installing some of the same executives who cut 80 percent of the social network’s staff, and even using the same email subject lines. He has promised “mass head-count reductions across the federal bureaucracy,” and is now racing to do just that.

Mr. Musk’s slash-first, fix-later approach to cost-cutting has been intentional throughout his career. And some of the early moves by the Trump administration to freeze funding for federal programs and entice federal workers to resign have led to mass confusion or are being legally challenged.