question:  What was the stoolie's job?
context: Those methane and ammonia planets, take it from me, they're the dead-end of creation, and why the Old Man ever thought them up I'll never know. It just ain't big enough for a gent of scope and talent; and the day the Solar System Customs caught me red-handed smuggling Kooleen crystals in from Mars, I knew I was in that corner, and sewed up tight. But—and this was the 'but' that was likely to deprive the System of my activities—even experimenting with them was illegal even if it needed to be done; also, I had promised not to rat on him before taking the job. So there I was, closeted with the ten members of the S.S. Customs Court, getting set to hear the gavel fall and the head man intone the sentence that would take me out of circulation for a long, long time. This bird, a little old hank of dried-up straw, joined his fingertips carefully, cleared his scrawny throat, and told me what for. "Aw, hell, judge, that's just one of those screwy fairy tales! How could any—" The senior judge rapped ferociously, and I skidded to a halt. That whole Kooleen caper: Had it been just a trap to lead me straight to this? Government men trapping me and then beaming at me. Those inhabitants were charming, just charming if you like scorpions. Well, a cross between a scorpion and a grasshopper, to be accurate. No doubt they had it figured that I'd gratefully throw myself into a sea of ammonia among man-size scorpions just for the hell of it. After all, in the pen a man can eat and breathe, and a guard won't reach in and nip off an arm or leg while he's got his back turned. At this strategic point, the enemy planted a stoolie on me. Either he was the world's champion liar or its bravest son, and either way I took my hat off to him.
output:  To convince Casey to change his mind
options:  To find out Casey's smuggling secrets  To get information from Casey to give to the S.S.C.  To become Casey's friend and confidante  To convince Casey to change his mind