President Trump’s 100th day in office started with what seemed to be a fresh and fast-escalating spat between the White House and Amazon.

Karoline Leavitt, the White House press secretary, came out swinging in her press briefing on Tuesday morning, accusing Amazon of being “hostile and political” after a report — disputed by the company — from Punchbowl News saying that the online retail giant would start displaying the exact cost of tariff-related price increases alongside all its products.

Displaying the import fees would have made clear to American consumers that they were shouldering the costs of Mr. Trump’s tariff policies rather than China, as he and his top officials have often claimed would be the case.

After the report was published, Mr. Trump spoke about it over the phone with Jeff Bezos, Amazon’s founder, according to three people familiar with the exchange. Amazon spokesmen hurriedly issued denials that the policy was going into effect, and by Tuesday afternoon Mr. Trump was back to praising Mr. Bezos.

“Jeff Bezos is very nice,” Mr. Trump said to reporters as he embarked on a trip to Michigan for a rally commemorating the first 100 days of his second term. “He solved the problem very quickly. He did the right thing. Good guy.”

This arc between Mr. Trump and Mr. Bezos that played out over just a few hours seemed telling. The Amazon mogul is among the billionaires who have gone to ever new lengths to get in good with this White House. Mr. Trump, in turn, has managed to woo such billionaires by promising he’d be better for business. And yet, at the first sign that Mr. Bezos might be prioritizing his businesses interests in a way that would harm Mr. Trump’s political fortunes, the White House didn’t hesitate to lash out publicly.