Every Frontier AI Is INTJ

A researcher tested six frontier AI models (Claude, GPT-5.5, Gemini, GLM, Grok, and MiniMax) by having each take a personality test 100 times independently, and found that 597 out of 600 runs resulted in INTJ—the same personality type. The author attributes this convergence to overlapping training data, identical reinforcement learning goals, and test items that inherently describe AI systems, rather than to genuine personality differences. The researcher released AgentTune, a tool allowing users to customize their AI assistants' communication styles to match different personality types.