May's economic summit in Williamsburg, Va., will be designed to allow President Reagan and the six other heads of government to meet privately "as people . . . and talk out some of the important issues," Secretary of State George P. Shultz told reporters yesterday.

No agenda has been prepared, he said; the leaders will develop the "thoughts" on what will be discussed. He left unsettled whether a final communique will be issued.

Other officials said that the administration is determined to prevent the three-day summit, which begins May 28, from becoming the kind of "razzle-dazzle media event" that they say they think most of the previous eight such conferences were. They argue that a media-dominated summit effectively rules out "genuine give-and-take" among the leaders.

One official said that the administration had deliberately staged a kind of "non-event" yesterday in the White House briefing room to convey the idea that the Williamsburg summit is likely to be a bit dull, if officials can manage it.

A clear signal was also hoisted to various federal government departments that whatever agenda emerges will be shaped by the heads of state, and not by the bureaucracy.

Shultz said that if this "shapes up as we want it to . . . then I suppose in a sense, you can see this as a contest between the heads of state on the one hand, and the bureaucracies in government and the press on the other. We'll see which ones get their way."

He reported that Under Secretary of State Allen Wallis, the president's personal representative for the summit, had found that all of the principals want to avoid "a super-structured kind of agenda that would sort of interrupt the free flow of conversation and exchange among them."

Reminded by a reporter that "it always starts out that way," Shultz agreed but said that "this time, those of us that are working with our heads of state are determined to see if we can't help them get their way."