Text of the agreement, reached in mid-December, has not been made public, and its exact contents have yet to be fully vetted by experts or the many businesses that have suffered from the protracted trade fight with China. The deal would reduce only a small portion of the tariffs that Mr. Trump imposed on $360 billion worth of Chinese goods, leaving many levies in place.

Officials from both countries have said the agreement includes commitments from China to increase purchases of American farm and energy products, places limits on Beijing’s ability to weaken its currency and provides enhanced protections to American companies doing business in China. The agreement also would reduce tariffs on about $120 billion worth of goods, and forestalled new tariffs that were scheduled for Dec. 15.

In announcing the agreement, the United States said that China’s farm purchases were expected to grow to at least $40 billion annually over a period of two years and that total exports of food, energy, manufactured goods and services to China would increase by a total of $200 billion. Chinese officials, however, have remained vague when describing what they agreed to buy and on what timeline.

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Details on China’s purchase commitments could be left out of the text of the agreement that is made public because officials have been concerned that commodities markets could be distorted if such information is released. The deal is expected to have some flexibility so that China can tailor its purchases to market demand.

Peter Navarro, the White House trade adviser, told CNBC on Tuesday that the American negotiating team was working out the final details before the signing, which had been expected during the first week of January.