A military prosecutor yesterday dismissed the Army's recruiting ads for doctors as "puffery" and "simply braggings on the part of the government" rather than promises that must be kept.

"Is that the government's position?" asked Lt. Col. John W. Hanft, the military judge presiding over the court martial of Capt. Leon T. Davis, the first military doctor to refuse to continue practicing on the ground the Army failed to live up to its promises.

Army Capt. James Lee Jr., the assistant prosecutor in the Davis trial at Fort McNair, did not answer the judge's question directly but continued to disparage Army recruiting ads.

"It's a commercial thing" done by advertising agencies in New York. "That's all it is," Lee told Davis during cross examination, drawing groans and giggles from the wives of Army doctors in the audience.

Davis is claiming that he is no longer in the Army, and should not be court martialed, because the Army broke its contract with him for medical services by failing to provide the promised modern equipment; equal pay for equal work; 30 days vacation a year, and time to attend medical meetings.

"These were simply braggings on the part of the government and not actual contractual rights," continued Lee in contending Davis could not be so "naive" as to take the promises seriously.

"Stay away from that," Hanft finally advised the prosecution.

Ever since the draft ended after the Vietnam War in 1973, military leaders have been stressing that the services must live up to promises made to volunteers. Davis is described by lawyers as the first officer since the All Volunteer Force came into being to literally make a federal case out of the obligation of the military to fulfil recruitment promises.

In testimony which dramatized that the military is signing up a new breed of soldier who considers serving a two-way contract, Davis said yesterday that he cut off his medical services after the Army breached his contract. He compared his sit-down strike to a builder who stops building or an accountant who stops accounting if the other party stops paying him.

"In a voluntary-contract military," Davis said from the witness stand yesterday, "the military is bound by its contracts." Since the Army is guilty of an "unequivocal breach" of his contract, Davis testified, "I am legally and moral excused" from fulfilling it.

The 30-year-old radiologist is charged with refusing to obey orders, desertion, going absent without leave and missing his deployment to Korea.