The principal architects of former president Carter's hostages release agreement, backed by the Republican chairman of the senate Foreign Relations Committee, said yesterday that the United States must honor its commitments to Iran or risk losing its international credibility.

In separate television interviews, former secretary of state Edmund S. Muskie; his former deputy and chief hostage negotiator, Warren Christopher; former White House counsel Lloyd Cutler and Sen. Charles Percy (R-Ill.) all condemned what Christopher called the "vile and disgusting" treatment suffered by the hostages during their 444 days of captivity, and they agreed that Iran deserves some unspecified "element of punishment," as Percy put it.

But they also stressed that to back out of the complex agreement to return the Iranian financial assets frozen in this country could have serious consequences for long-range U.S. interests. As Christopher put it on "Face the Nation" (CBS, WDVM), "The word of the United States is a very important commodity, and I want to keep it pure."

The new administration of President Reagan has said it plans to study carefully the fine print of the agreement negotiated in the final hours of Carter's presidency. That, coupled with growing national anger at the information now emerging about the Iranians' harsh treatment of the captives, has touched off speculation that Reagan might repudiate the agreement and confiscate those Iranian assests still under American control.

However, Percy, speaking on "Meet the Press" (NBC, WRC), added a bipartisan note to the arguments for honoring the agreement. While noting that he has not yet got full details, the senator said: "From what I have seen, it would be dishonorable for this nation not to adhere to the agreements approved by President Carter."

Elaborating on that point, Christopher noted the problems that an American reversal would cause for Algeria, which played a crucial intermediary role in arranging the deal, and for other countries that helped to pressure and cajole Iran's revolutionary leaders. He said:

"Failure to carry out the agreement with respect to Algeria would be a very serious slap in the face. . . . Other countries who helped us through this excruciating 444-day period would be very surprised if the United States, having negotiated an agreement within good faith, did not carry it out."

He called the agreement "a sound one from a financial standpoint," stressed that "above all the hostages are free and home," and said he believed the new administraton would reach that conclusion when it completes its review.

Essentially the same arguments were made by Muskie and Cutler in a joint appearance on "Issues and Answers" (ABC, WJLA).

Despite their support for the agreement, all four men had harsh words about Iran's actions, and agreed, as Muskie said, that it would be "quite some time" before the United States and Iran are able to resume anything approaching normal relations. Percy, while saying Iran should "pay a price" for its "barbaric behavior," appeared to rule out reprisals of military nature and suggested instead that any condemnatory action should come from the international community.

Cutler, talking about the need to prevent similiar accidents in the future, said, "The ideal solution, if it can be negotiated, would be an international understanding which could take the form of an amendment to the Vienna Convention governing diplomatic immunity, that once the World Court determines that a nation has illegally detained the diplomats of another nation, then it becomes the obligation of all nations to withdraw their own embassies, and to prevent the violator from having any embassies in other countries."

Percy said the Foreign Relations Committee will hold hearings, most likely in February, "to see what we can learn from this and to prevent it every happening again." He added, "We'll pick it up with the seizure of the hostages and all that transpired in that period, but essentially we will be looking to the future."

His words indicated that Percy, unlike some ultra-partisan Republicans in Congress, wants to avoid turning the expected hearings into a full-scale inquiry into U.S. policy toward Iran during the Carter administration. Hearings limited to the scope proposed by Percy would avoid turning the inquiry into an examination of charges that Carter administration actions contributed to the fall of the late Shah Mohammad Reza Pahlavi's regime, helped put the strategically important Persian Gulf country with its vital oil supplies into unfriendly hands and led ultimately to the taking of the hostages.

Christopher, in his interview, hinited strongly that the United States was fearful, right up to the last moment, that opposition from anit-American Iranian militants and foes of the civil authority there might scuttle the agreement before the hostages could be released.

It was his "own estimate," he said, that it wasn't until the period around Christmas that the Iranian government was able to wrest control of the hostages fully from their militant captors. "I would say that prior to Christmastime, the control was divided between the Iranian government and the militants, and it was a very chancy thing almost up until the last moment," he said.

At another point, responding to questions about last-minute delays in the captives' departure from Tehran, he said: "The government of Iran had to bring the hostages from various locations in Tehran to the airport and get them on board the aircraft. History will show that that turned out to be a much more difficult endeavor than they had anticipated. And indeed, I think it probably was a very close matter."

He continued, "It was difficult because there continued to be opposition right up to the last moment to putting the hostages on board the aircraft. I think we probably owe a great deal to the Alerians' insistence that the hostages be put on board the aircraft."

Various Carter administration officials involved in the negotiations said yesterday they couldn't elaborate on Christopher's remarks because they did not have the information to which he was privy from his negotiating vantage in Algiers.

However, the officials did say they were aware that opposition by Iranian militants to the deal continued right up to last Tuesday when the captives finally were freed.

One added that during the frantic final hours on Tuesday, the State Department received a number of conflicting reports about what was happening in Tehran, including one that a group of hostages had been stopped en route to the airport and returned to confinement. However, the official added, while the department was trying frantically to check these reports, the word came that the captives finally were in the air on their way to freedom.