"I saw a limit to what I was giving as kind of a scam I was running on the KGB, by giving them people that I knew were their double agents fed to us"

In this quote, Aldrich Ames, a former CIA officer who was founded guilty of spying for the Soviet Union and Russia, is admitting that he intentionally supplied the KGB with CIA agents who he understood were working as double agents. He describes what he was doing as a "scam", suggesting that he was purposefully misleading the KGB in order to secure himself and his own espionage activities. It is likely that Ames saw a limit to how much he could continue to deceive the KGB and realized that providing them with unreliable info might eventually put his own position and security at risk.