President Carter yesterday ended his talks at Camp David with secretary of state-designate Edmund S. Muskie and other top national security officials, but the White House gave no indication of what decisions were made.

Instead, a brief statement by the White House press office said only that there was "detailed discussion" of the role that Muskie will play in the administration.

Muskie, Democratic senator from Maine, was named secretary of state last Tuesday after Cyrus R. Vance resigned in protest against the ill-fated attempt to rescue the American hostages in Tehran.

Vance's resignation also stirred considerable discussion about whether he had lost a power struggle with Carter's national security affairs adviser, Zbigniew Brzezinski. And since there had been intense speculation about whether Muskie or Brzezinski will be the most influential force in shaping administration foreign policy.

The White House statement said only that there had been discussion at Camp David of Muskie's role "in advising the president on policy issues, in public presentation of the administration's foreign policies and in working closely with Congress."

It said also that "the president emphasized his desire to maintain closer personal contact" with officials of the State Department, Defense Department and National Security Council staff.

In addition, the statement said, the talks "covered a number of major policy issues and strategies for dealing with them." While these issues are known to have included the Iran crisis and the tension between Washington and the Soviet Union, the statement did not elaborate.

In a related development, Ambassador Thomas Watson Jr. returned to Moscow after several days of consultations here. Reliable sources said Watson, former board chairman of International Business Machines Corp., had come to Washington with a tentative decision to resign in the wake of Vance's departure.

However, the sources continued, after talking with Muskie and a number of other senior administration officials, Watson agreed to remain at his Moscow post for the time being.