General Accounting Office, the congressional watchdog agency that is supposed to spot flaws in federal programs, gave out an unusually good report card yesterday.

On a scale of 1 to 10, the GAO gave the Office of Personel Management what amounts to an 8-plus rating for its efforts during its first year of operation.

OPM is one of several new agencies that sprang from the forehead of the Civil Service Commission when it was abolished, as part of President Carter's plan to streamline and reform the bureaucracy. Overall, the GAO said the new agency is doing what it was supposed to do, and doing it rather well.

GAO was critical, however, of the use of "early retirement" authority under the civil service reforms. OPM can give agencies permission to offer employes early-out retirement (as early as age 43 in some cases) when their agencies are undergoing layoffs or reorganizations. OPM was the first agency to use the early-out option, and many senior-level employes used it to quit early.

The congressional watchdog agency also said the OPM should keep a closer a eye on merit pay plans and job appraisal systems being set up by agencies, to make sure they follow merit principles and don't become political devices to reward the faithful and punish the politically uncooperative.

President Carter said he was delighted with the generally glowing GAO report, and had high praise for OPM chief Alan K. Campbell. Carter said he and Campbell would look into criticisms of the OPM, but that he is satisfied the new agency has made good progress toward reforming the bureaucracy.