The story that the CIA did this is mostly myth created by CIA people to enhance the reputation of the CIA in the eyes of US White House and Congress. CIA had Kermit Roosevelt Jr. (Teddy's grandson) in Iran working on it, but he accomplished little, and the CIA sent him orders to stop a couple of days before the coup. He pretended not to get the message and kept trying, but probably without much effect. Mohammad Mosaddegh lost power when the ayatollahs raised their opposition to his rule. Roosevelt then returned to the US and collected all the credit.

This PR coup led to Eisenhower giving Dulles of the CIA a couple of fighter planes to use in Guatemala to remove Jacobo Arbenz from power, which was the CIA's pinnacle of success, strengthening the CIA's reputation even more and leading to the agency's mediocre record thereafter.