The Supreme Court, outside of its opinions and occasional speeches by justices, still provides little or no information to the public about how it operates. No public information officer is likely to be able to change that.

But the arrival this term of a new public information officer, former Washington Star reporter Toni House, has helped defuse what was once downright ugly tension between court officialdom and the media.

The old atmosphere was reflected in many ways: by a lack of response to even the most innocuous questions; by a prohibition on conversations between reporters and court employes--even the craftsman who built the chair for Justice Sandra Day O'Connor; by an informal raid by an assistant marshal to retrieve court telephone directories from reporters' desks after the phone listings were inadvertently distributed in the press room.

Former information officer Barrett McGurn generally spoke only two words: "No comment." It was a joke even among some justices.

The new atmosphere was exemplified by the sight of House rushing down the hall in her stocking feet one evening earlier this year to make sure waiting reporters got copies of a court order involving an execution.

The most obvious improvement is simply one of mood: House is cheerful and friendly; McGurn seemed frightened of the press. But a mood is contagious, and other court officials now seem more accessible. The press room staff--Kathleen L. Arberg, Edward Turner and intern Nancy Firestine--is now free to cooperate openly with routine requests from reporters. The old staff often had to whisper its way around McGurn.

That may not mean much if judged by the standards of most government agencies. But at the Supreme Court, it was considered a triumph when House managed to obtain a schedule of commencement speeches being given by the justices this year.

Sources with the congressional committees that deal with the court also say their lines of communication have improved since House arrived.

"There appeared to me and to the people I talked to in the building that there was a hostility that had grown up, almost a wall between the public information office and the press room," House said. "Obviously, there are times when we are in adversarial positions, but I don't see why that precludes an aura of general cooperation and friendliness." THE BIG ONES . . .

The court will have ruled on 183 cases when the term ends in late June or early July--about 30 more than the average over the past decade. Among the 50 or 60 issues still awaiting resolution are abortion regulation, the legislative veto, tuition tax deductions and the dispute between Sony Corp. and the entertainment industry over the legality of home video taping.

If the size of the crowd waiting for a particular decision is any reflection of popular interest, the Sony case wins hands down. Paralegals, secretaries from law firms and even a few high-priced lawyers have been lining up each opinion day for months awating that ruling. THE CAFETERIA CASE . . .

While the outside world focuses on those cases, some Supreme Court employes have been talking about what could be called the case of Certain Members of the Cafeteria Committee v. Justice Sandra Day O'Connor.

The issue was which of several competing food service companies would get the contract to run the Supreme Court cafeteria. The opinion, according to court tradition, was supposed to be decided democratically and submitted to the chief justice for approval by a committee of eight or nine members, composed of court employes and one justice: O'Connor.

The complaint would accuse O'Connor of overreaching. The outcome was decided by a minority vote--hers. As a result, several members of the committee have resigned in protest.

Court employes said O'Connor has been complaining about the cafeteria food since she came to the court last year. They said that at one point she tried to get one concessionaire replaced with another whose food she had tasted at a nearby government building.

The committee began considering applications months ago, conducting interviews with competing companies and inspecting their other facilities. O'Connor, busy being a justice, did not participate and did not attend committee meetings.

But when it came time to make a recommendation, the other members found it was res judicata--already decided. Employes say O'Connor disregarded the recommendations of the others, chose the Macke Co. on her own, and submitted her choice to Chief Justice Warren E. Burger, who approved it. Macke now has the contract.

O'Connor commented through an aide that although she was "unable to attend a number of meetings," she had reviewed meeting tapes, written proposals and "everyone's recommendations" before forwarding her choice to the chief justice.

Some employes say it was not up to her to make a decision. Lawyers might call it a loss by vis major--an insuperable force.