The instructions for another rendezvous might have been dreamed up by John le Carre.

According to undisputed testimony at the spy trial of former CIA officer William Kampiles in U.S. District Court here, he was to have gone back to Greece last summer to meet his Soviet contact, but only after following an elaborate script.

First, he was to have sent a coded "Happy Birthday" message to the Russian contact at a so-called "accommodation address" in Athens which the officer. Soviet military attache Michael Zavali, had provided him.If Kampiles had written "Happy Birthday" . . . I'm well . . ." that would have meant he was coming. "I'm not well" would have meant he couldn't make it.

Once back in Athens, where he first met "Michael" last winter, Kampiles was to have gone to the Athens Stadium, made his way to a cobblestone path to a certain telephone pole and stuck a thumbtack in it.

The tack, jurors here have been told, would have been the clandestine signal to "Michael" to meet Kampiles in person the following Saturday night at a nearby Pizzeria in the Greek capital.

Testifying yesterday at Kampiles' espionage trial here, an FBI counter-intelligence expert, Cornelius G. Sullivan, said the intricate arrangements strongly suggested that Kampiles was a fully "recruited agent" after he first meetings with "Michael" last winter.

The government contends that he sold the Russians a top-secret manual on the KH11 spy satellite on that first trip for $3,000.

Kampiles has pleaded not guilty, contending through his lawyer that he "conned" the Russians out of their money by promising them important American secrets without actually giving them any.

But FBI agent Sullivan said the fact that the Russians had provided him with "an accommodation address" (to which to send the birthday card), a "signal site" (the telephone pole) and a "meeting site" (the pizzeria) clearly signified that Kampiles had already been hired by the other side.

Under cross-examination by Kampiles' defense counsel, Michael Monico, the FBI agent also held firmly to his view that the Russians would never have paid Kampiles the $3,000 he acknowledges he got from them without receiving solid information in return.

"The Soviets are very pragmatic, cynical people," Sullivan testified, "They will not buy a pig in a poke."

In other testimony yesterday, a Central Intelligence Agency official who once won a medal for his work on the KH11 said that loss of the top-secret manual to the Russians could compromise its effectiveness. Leslie C. Dirks, the CIA deputy director for science and technology, said that one page of the document describes the limitations in the satellite's geographic coverage and another page provides an example of the quality of the photographs.

Dirks, who won a distinguished intelligence medal from the CIA for his contributions to the KH11 system, said that knowledge of the geographic limitations could put the Soviet Union in a position to avoid the satellite's surveillance altogether and knowledge of the quality of its photographs could enavle the Soviets to devise effective camouflage.

In what government lawyers attacked as a "fishing expedition," defense attorney Monico brought up the death of former CIA officer John Paisley, who was found dead in Chesapeake Bay several weeks ago, his body weighted down by a pair of diving belts.

Maryland State Police have said they think Paisley's death was a suicide but are still officially calling it "an undetermined death." Monico has asked for any CIA files that might in any way connect Paisley with the KH11, but the government contends that all he ever got was information that the satellite produced.

U.S. Attorney David Ready told the court that there is nothing connecting Paisley "with any compromise of the KH11" or "with any matter at issue in this case."