The annual meetings of the International Monetary Fund and World Bank wound up on an uneasy note today as the delegates headed home clearly worried about the global banking system, but unsure whether a crisis of the magnitude of the 1930s is in the offing.

The assessment that came most easily to the lips of private bankers and government officials is that the situation is "managable." But they coupled that assurance with an "if" -- if the developing countries of the Third World such as Mexico and others who may face defaults on their debt abandon some of their excessive spending habits.

In closing remarks here, World Bank President A.W. Clausen said that "a great deal has been said during our meetings about this being a period of grave economic and financial crisis. But we should not be overwhelmed by the present situation."

Similarly, IMF Managing Director Jacques de Larosiere avoided alarmist language. In concluding remarks to the joint session, he said that the world economy was "troubled," but that there had been a wide consensus here that the situation calls for continued fiscal discipline.

"This policy approach recognizes that current problems are deep-seated, that fundamental policies of adjustment are called for, and that the process of adjustment cannot be cut short through resort to reflation of demand or to protectionism," de Larosiere said.

The United States, which most other nations here have criticized severely for refusing to commit itself in advance to a "substantial" increase in IMF lending resources, nonetheless expects that some agreement on IMF resources will be reached next April when the Interim Commmittee meets in Washington.

Princeton economics professor Peter Kenen, an attendant at the sessions, articulated a thought that is widely held here: "If somebody had to be in trouble, I'm glad it was Mexico first, because nothing else would have served to focus American attention to the problem." Implicit in Kenen's remark is that the United States has been willing to move to solve the Mexican crisis because so many large American banks are heavily involved.

Clausen said that broad agreement had been reached at the meetings herethat the commercial banks facing the overhanging debt problems in Mexico, Brazil, and other countries in Latin America, and in Eastern Europe would not stop their lending abruptly but continue to make loans "at a prudent level." Clausen suggested that an abrupt cut-off of loans might be just as dangerous as excessive lending.

"There is a cautious mood among bankers," Clausen said. For that reason, the World Bank's effort to promote increased cofinancing with private banks would become especially important, he said. Clausen hopes that the World Bank's participation with private institutions will increase the flow of funds to the Third World by providing what amounts to an umbrella for the private banks, even if the bank's own resources are not expanded as much as he would like.

If the annual meeting did not come up with a broad-scale rescue program for all the world's economic troubles, nonetheless there were some specific results at the Toronto meeting:

Clausen announced that the World Bank had agreed in principle, at the request of the Lebanese government, "to take the initiative" in exploring the dimensions of the reconstruction problem in that battered country. The bank apparently will try to form a consortium of lenders once it gets a fix on the total amount needed.

The bank's soft-loan agency, the International Development Association, was assured of continuity through fiscal 1984, when all donor nations except the United States agreed to put up an extra $2 billion for that year. Coupled with the money stretched into 1984 out of the original American commitment that was supposed to have been concluded by fiscal 1983, the IDA will have between $3 billion and $3.5 billion to expend in 1984.

Clausen confirmed a Washington Post report earlier this week that the next IDA program -- IDA-7, beginning in fiscal 1985 -- would have a new shape, with some of its loans carrying interest charges for the first time, in addition to the zero-interest loans currently provided.