President Carter has obtained pledges from Egypt and Israel to stop propaganda attacks on one another and is silencing his administration's own frequently blunt criticisms of the two governments, senior U.S. officials reported yesterday.

Carter, Secretary of State Cyrus R. Vance and national security affairs adviser Zibigniew Brzezinski also decided at a White House meeting yesterday to avoid detailed public discussion of the American role in pursuing a peace settlement between the two countries in advance of the Sept. 5 summit meeting of Carter, Israeli Prime Minister Menachem Begin and Egyptian President Anwar Sadat, the officials said.

Vance secured the pledges of a new truce in the recently resumed campaigns of invective between Egypt and Israel on his five-day trip to the Middle East, which ended Wednesday. He reported to Carter yesterday on the decisions by Begin and Sadat to come to Camp David next month.

White House press secretary Jody Powell, evidently alluding to the decision to say as little as possible in public about the Middle East until the summit is over, deflected reporters' questions at his regular briefing by saying that "a period of quiet, intense discussions is necessary."

"It is not a time for us to be commenting, and we are not going to be in the commenting game," a State Department official observed.

Public comments by the administration portraying Israel as lacking flexibility in negotiations with Egypt have been a major irritant between Washington and Israel over the past year.

Intense debate about continuing to criticize the Israelis publicly began in the White House after Vice President Mondale returned from a trip to Israel in July. Mondale began to argue that the Israelis would not move as long as they felt they were being unfairly "picked on" by the United States, a well-informed administration official said.

That debate evidently had an impact on the administration's decision to make its harshest public criticism of Sadat when the Egyptian leader announced on July 30 that he was halting all direct contacts with the Israelis until they made new concessions.

Reading a statement approved by President Carter and dictated over the telephone to him by Vance the following day, State Department spokesman Hodding Carter called the decision by Sadat "very disappointing."

The words stung the Egyptians, who had been countering criticism from Arab radicals with the argument that Sadat's peace initiative had won him a special place in official and public American opinion.

Hodding Carter resolutely refused at the regular State Department briefing yesterday to discuss reports of Israeli use of American supplied weapons in a bombing raid into Lebanon last week. Earlier this year, the administration had publicized its disapproval in a similar case.

The State Department spokesman also sidestepped all questions about Vance's use TUesday night of the phrase "full partner" to describe the American role in the Camp David summit. Vance was speaking to a joint news conference with Sadat, who has used the phrase to demand that the United States put forward its own proposals for peace, which he hopes will resemble the Arab view more than that of Begin's government.

Although officials would not discuss it for quotation or privately, the administration appeared by its muteness at the White House and State Department briefings to be trying to stay out of the semantic thicket of Middle East code words and phrases that could cause public opinion problems for Carter, Begin or Sadat in the weeks leading up to the summit.

That consideration was also an important element in Vance's suggestion to Begin and particularly Sadat that attacks on one another through the state-controlled media of their countries could upset the meeting, which will seek a resumption of direct negotiations for a final peace settlement.

Begin publicly complained of the recent "totally negative Egyptian statements" about him during Vance's visit. Sadat has called the Israell leader the only obstacle to peace and Cairo Radio labeled him a racist in a commentary last week.

"Both sides agreed to knock it off," a State Department source said. "They both want this summit meeting to produce results, and they are not going to endanger it. I don't think the United States will be providing interpretation that might upset things, either."