Jacob Coxson

Jacob Coxon is a former AI pretraining researcher who worked at OpenAI from 2023 to mid-2026 and then at Anthropic for approximately four months before resigning in September 2026. He is best known for a widely viewed social media post announcing his departure from Anthropic in which he stated that frontier AI labs are racing toward self-improving superintelligence and warned that AI could pose an existential threat to humanity within the decade. He co-authored the GPT-4o system card during his time at OpenAI and previously conducted research applying Bayesian analysis to medical genomics.