Why frontier LLMs solve your CTF challenges in minutes (and how to fix it)

I ran a small internal CTF for our team last month. Twelve challenges, expected solve time around six hours for a strong player. The first three fell in under ten minutes - not because the players were geniuses, but because they pasted the prompt into an LLM and waited. This is not a rant about cheating. The same thing is happening in public CTFs, and it's exposing a real engineering problem: most CTF challenges were designed assuming the solver is a human reading a static artifact. Frontier models are extremely good at reading static artifacts.