Virginia State Attorney General J. Marshall Coleman announced yesterday that Thomas Edward Bruce, the 28-year-old Vietnam veteran who was banished from the state last week by an unusual out-of-court agreement, can return home.

Bruce has been living in Washington since he was released from a Charlottesville jail after signing a controversial probation agreement that requires that he remain out of Virginia for 10 years.

Following a brief investigation by his office, Coleman yesterday declared that the banishment provision "is not enforceable and may violate public policy."

Coleman said he and the state probation officer who signed the agreement have agreed to ask a state circuit court judge to order the banishment provision dropped. The agreement had been drafted to spell out new terms of Bruce's probation under a 1978 shooting conviction.

Bruce, classified as 100 percent mentally disabled as the result of his Vietnam service in the Army, had been jailed by Albemarle County authorities on a charge of murdering a friend in November 1978. That charge was dropped at the same time that Bruce signed the new probation agreement.

Coleman has been sharply critical of the agreement. "If the crime is serious enough to warrant banishment from the state, it is serious enough to warrant incarceration," he said. Virginia should not send its problems to other states. We certainly do not want other states to send their criminals to Virginia."

Bruce, who now lives in a small Northwest Washington apartment, could not be reached for comment.

On Monday, Bruce told a reporter "the state of Virginia has done me a great injustice" and said he wanted very much to return to his rural home of Esmont, 20 miles south of Charlottesville.

Coleman said Bruce will be free to return to the state, but will remain under continued supervised probation and must continue to receive psychiatric treatment for the combat-related mental disorder he suffered in Vietnam in 1969.