A competitive security researcher who won DownUnderCTF multiple times with Blitzkrieg and placed in the top 10 on CTFTime with TheHackersCrew has declared the open CTF scene dead. What killed it was not AI assistance itself, but GPT-4 making medium-difficulty challenges one-shottable and Claude Opus 4.5 pushing agent-solvability into hard territory. Claude Code packaged everything into a CLI, letting teams orchestrate agents across challenges in minutes.

The author argues GPT-5.5 Pro can one-shot Insane-difficulty heap pwn challenges on HackTheBox, making the competition effectively pay-to-win. Open online CTFs now measure orchestration and token budget rather than security skill. The CTFTime leaderboard stopped reflecting human growth, and the feedback loop where beginners climbed by solving more challenges has collapsed.

The author recommends picoGym and HackTheBox over public CTFs since the latter now reward prompt engineering more than learning. Organizers can't block Claude Code with refusal tricks, and the competitive CTF format has been hollowed out.