Everyone knew that Tommy wasn’t really an undercover agent, although he pretended to be. He would come into a room sometimes and say something enigmatic, like “The robin is on the bough” or “The curling rod is no good for a doctors' conference”. He clearly intended these to sound like some secret code that only an anonymous agent in the room would understand. It was a bit silly but kind of fun! Most went along with it.
People would go up to Tommy and tell him all sorts of things. If they knew he was a real spy they would’ve made their facts up to put him off the scent. But since he wasn’t a real spy, but only a pretend, they frequently related who had stolen what and who avoided their income tax and where the best place was to get illegal drugs and so on.
That was why Tommy was in fact the most successful undercover agent in the country.