The CIA insists it is no "big deal," but its reviewers stubbed their toes this month on a piece of fiction.

They demanded the deletion -- from a novel -- of the name of an operative whose cover had already been "blown" by the CIA itself.

The situation was disclosed yesterday by former CIA officer Frank Snepp who had submitted the manuscript of a new book to the agency for prepublication review that the CIA demands of its alumni.

The CIA's censors found no legal problems with the book -- a fictional account of President Kennedy's assassination in 1963 -- except for one thing. aOn July 3, they informed Snepp that the name of a CIA officer, whose real identity Snepp had chosen to use along with a number of others, "must be deleted."

"As you may be aware," CIA Assistant General Counsel John F. Peyton Jr. wrote Snepp in the July 3 letter, "you have used the correct name of an agency officer whose association with the agency remains classified."

Snepp was astounded. A CIA critic, he had been sensitized by a Supreme Court decision in February ordering him to relinquish $140,000 in profits from his first book for failing to submit to CIA review. This time, he said, he had been especially careful to tell no tales out of school. The name of the man in question, he said, had been plucked out of another book on the Kennedy assassination, "Legend: The Secret World of Lee Harvey Oswald," by Edward Jay Epstein.

What's more, Snepp said, the man had also been named in several other books, including one that had been cleared by the CIA. Snepp refused, for the sake of good form, to identify that tome, but he said it was written by David A. Phillips, former CIA staiton chief in Mexico City and currently chairman of the pro-CIA Association of Former Intelligence Officers. He wrote "The Night Watch," an account of his years with the agency that the CIA cleared several years ago.

Belatedly apprised of all this, Peyton told Snepp's lawyer Mark Lynch in a July 8 telephone call that the CIA was withdrawing its demand. But Peyton, Snepp said, told Lynch that "the name was still so sensitive they were going to ask me to delete it voluntarily."

"That gives you an idea of how good the clearance process is," Snepp protested. "They'd allowed one of their 'good old boys' [Phillips] to release a name and now they were trying to get me to help squeeze the toothpaste back in the tube."

At a meeting with Snepp and Lynch Friday, Peyton emphasized the request in person. "He said the name in question had to do with certain operations directed at the Soviet Union and with very important liaison operations with foreign intelligence services that the CIA considers crucial," Snepp said yesterday.

Snepp agreed to use a pseudonyn, although not without a certain sense of satisfaction. "In all my writings and speaking engagements," he told Peyton in a letter mailed Saturday, "I have gone to great lengths to avoid exposing a secret, a name or an intelligence source whose confidentiality is crucial to the effective functioning of our intelligence services. Although your own review staff has shown itself to be somewhat less diligent, I will not violate my own moral responsibility."

CIA spokesman Herbert Hetu confirmed yesterday afternoon that the name of the CIA man in question, although he has "retired under cover," has been publicized before. He said he did not know what represenstations Peyton might have made in seeking anonymity now. "We just don't want to call attention to his name again needlessly," Hetu declared. "It wasn't a big deal."