The three authors of the latest Washington political mystery-thriller, the Camp David summit, have now left enough clues in sight for their audience to begin to piece together an outline for the free-form drama, currently playing against a backdrop of war and peace in the Middle East.

After six days resembling a warmed-over version of the endless obscurity of "Waiting for Godot," the production staged by President Carter at his super-exclusive retreat in Maryland's Catoctin Mountains moves into its decisive stage today.

Diplomats, journalists and other analysts who have been reduced to reading the muddiest of tea leaves for assessments of the talks involving Carter. Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin, will now watch for an event likely to signal a resolution of some kind be it success or failure.

That event, which could come today, according to sources familiar with some of the procedural aspects of the summit, would be a joint meeting of aides of the three leaders to begin drafting documents to spell out the details of decisions or deadlocks reached by the three in their talks.

For the cognoscenti of this kind of summitry, the holding of such a meeting could be the equivalent of the white smoke that curls up from the Sistine Chapel Stack to announce that balloting for a new pope has concluded. As long as a serious drafting session doesn't happen, continuing deadlock is the most likely assumption.

While Carter, Begin and Sadat have met together for a total of seven hours, their aides have not engaged in any three-way sessions. This has created a dual U.S. role thus far - direct negotiating by Carter with his two counterparts, and a "shuttle" movement back and forth between the Egyptian and Israeli foreign ministers by Secretary of State Cyrus R. Vance.

Conducted in a total news blackout, the shuttle lacks both the distances and drama of the mediation efforts by Vance's predecessor. Henry A. Kissinger, who consciously used the flow of news to help his diplomatic goals and who filled his trips with tidbits offered by a "a senior official."

"In a strange way, I think we may be able to put together a more accurate picture of what is or is not happening under this blackout than under Kissinger's management tactics," said one Iraeli journalist who covered Kissinger's trips and who has had exceptionally good access to accounts of the color and procedural aspects of the Camp David meetings. Like his U.S. and Egyptian colleagues, he had been shut out of the substance of the current talks and has had to construct ambiguous analyses using the few details available.

The "clues" encompass a white yarmulke Carter wore Friday evening a walk he did not take, his note-writing habits, a surprisingly introverted Sadat, a larger role in the summit for Vice President Mondale than had been forecast, and a few other scraps of information about scheduling and atmospherics.

Putting together the few details available, diplomatic analysts have come up with some educated guesses, based on years of watching high-level conferences, about what seems to be going on in the sealed-off retreat.

Including private sessions between Carter and Begin, the Americans have spent more than 13 hours of publicly announced meetings with the Israelis, while spending one-third less time with the Egyptians.

Moreover, the only "bilateral" social contacts of the summit have involved President and Rosalynn Carter and Prime Minister and Aliza Begin. The four went for an hour's stroll on Wednesday. On Friday Carter donned the yarmulke at a kosher dinner hosted by Begin that featured traditional Sabbath songs.

The fact that Sadat brought neither his wife nor a delegation as strong as Israel's which features the formidable personalities of Foreign Minister Moshe Dayan and Defense Minister Ezer Weizman, helps account to some extent for this disparity.

But tactical bargaining reasons are also likely to be involved. After hearing out the positions of both men, Carter appears to have been bearing down on the Israelis for change. Sadat gives an impression of watching and waiting in this phase of the talks while Carter seeks compromises on the troublesome West Bank and Palestinian representation problems.

Sadat's reserve was underscored yesterday as Egyptian sources began to gell reporters that the meetings were not going as well as he had hoped and that the was still waiting for signs of fundamental change in the Israeli position. These sources repeated pre-summit Egyptian estimates that total failure was preferable to a patched-up agreement.

Mondale's presence at sessions Wednesday, Thursday and Friday reinforced that impression. U.S. diplomatic sources said before the summit that Mondale was especially well-placed to reassure Israel and American Jews of the administration's support while asking Begin to make concessions.

One detail that has filtered out of the Carter-Begin-Sadat meetings is that Carter is reportedly setting down could be used to assess responsibility full notes as the talks go on. These in a public report if the summit breaks down, but U.S. sources in the past have portrayed the failure of Sadat and Begin to take their previous two meetings as one factor in their later mutual disappointment and misunderstandings.

Such small details stand out with dazzling clarity in the blackout on information that Carter has decreed for the talks. But reading meaning into them, as many diplomats and journalists are contrained to do. remains highly precarious.

On Friday Carter held a pair of meetings that touched off speculation when it was noticed that he wal Sadat's lodge, although he stayed in his own to receive Begin. Nothing more substantive was involved, it turns out, than the fact that Begin, a head of government noted for his Old World sense of courtesy and protocol, strongly insisted on walking over to visit his host, who is, of course, a head of state.