The Senate Intelligence Committee closed ranks momentarily yesterday and approved an intricate oversight bill aimed at bringing all U.S. intelligence activities under some form of congressional supervision.

The measure, which was left deliberately vague about what might happen in especially sensitive cases, to withhold certain secrets as commander-in-chief and to protect them from "unauthorized disclosure."

Anxious to keep it from turning into a "Christmas tree" bill full of controversial amendments on the Senate floor, committee members agreed not to tack on any riders before it gets there.

Sen. Daniel Patrick Moynihan (D-N.Y.) served notice, however, that he will press for a prohibition on use of journalists, clergy or academics as spies when the measure comes up for a Senate vote.

Chairman Birch Bayh (D-Ind.) said he recognized the oversight bill falls far short of the comprehensive charter for the CIA and the rest of U.S. intelligence community, which the committee had originally hoped to pass. But he called it "a significant and important first step."

The charter began as an elaborately detailed effort to curb the misdeeds of the CIA, the FBI and other U.S. intelligence agencies, but it evolved with the changing public mood into a complicated license for spying here and abroad that pleased neither liberals nor conservatives.

With the charter doomed by election year pressures, the oversight bill was carved out of it this week following concessions to White House and CIA lawyers. It covers far more intelligence operations than any law, but it is also subject to conflicting interpretations that future presidents and congresses can squabble about and resolve in accord with the temper of the times. For the Carter administration, it serves primarily to codify its existing practices of telling a select few in Congress most, but not all, of its secrets.

Bayh said it was the only measure that had a chance of passage.

"I don't know of a better example where a quarter of a loaf is better than none," he told reporters after the brief meeting.

Bayh said he hoped he could convince Senate Democratic and Republican leaders that the measure can be steered through the Senate without addition of any amendments, including Moynihan's.

The pared-down result of the work that began in 1975 with congressional and executive branch investigations of CIA and FBI abuses of power, the bill would:

Provide greater secrecy for the CIA's covert actions by repealing the 1974 Hughes-Ryan Amendment and restricting the disclosure of such activities to the Senate and House Intelligence committees, instead of the eight committees now entitled to such knowledge.

Call for prior notice to the two Intelligence committees of all "significant" intelligence activities undertaken by any government agency, including the CIA's covert actions, but subject to two broadly stated exceptions demanding by the Carter administration.

Permit the president, in "extraordinary circumstances," to limit prior notification to eight congressional leaders.

Allow the president, in undefined circumstances, to provide no advance notice. The bill contemplates this in preamble, which the administration insisted upon, recognizing both the president's constitutional powers and the need of the executive branch to protect "classified information and information relating to intelligence sources and methods" from unauthorized disclosure.

Require the CIA and all other government agencies involved in intelligence work to provide the two Intelligence committees with any after-the-fact information they request and with reports of "any illegal intelligence activity or significant intelligence failure." Again, however, the administration would be entitled to determine whether such disclosures are consistent with the president's constitutional powers and with the need to prevent unauthorized disclosures.

Oblige the president to inform the two Intelligence committees "in a timely fashion" of any covert actions abroad that he chose not to tell them about in advance. This obligation, however, would not apply to intelligence-gathering operations, intelligence failures, illegal activities or any other after-the-fact details that the president might choose not to disclose.

On balance, it appeared that civil liberties groups were far happier with the bill than supporters of a stronger hand for the intelligence community who have attacked the measure as badly drafted.

American Civil Liberties Union spokesman Jerry Berman said he was pleased with the bill.

"What it does is freeze into law what is current practice," he said. "Another admninistration might not have continued the current practice."

At the committee meeting, the last obstacle to approving the bill without any amendments disapppeared when Sen. John H. Chafee (R-R.I.) agreed to withdraw a rider making it a crime to disclose the names of U.S. intelligence operatives abroad. He said he would not submit it on the floor either, but in turn, he extracted what he called "a blood oath" from the other committee members present to oppose Moynihan's rider on the Senate floor.

Moynihan, who turned up a few minutes later, said he intended to press ahead anyway and doubted that his amendment would open the door to a "Christmas tree" package.