Meet GPT-Red: an LLM super-hacker OpenAI built to make its models safer

OpenAI built GPT-Red, an AI model trained to attack other AI systems, and uses it to find security weaknesses before releasing new versions like GPT-5.6. GPT-Red specializes in finding prompt injection attacks (where hackers hide malicious instructions in text that the AI reads), including a previously unknown attack type called fake chain of thought where false information is inserted into the AI's internal reasoning process. The model trains against other AI systems in a self-play loop (where it repeatedly attacks while others defend) within simulated real-world scenarios, making it better at finding effective attacks than human testers alone.