Jiayi Weng(@Trinkle23897 ):As GPT-5 launches today, it's hard to forget the first ChatGPT-4 model called 0915-gpt4 internally at 2022. @shengjia_zhao did RM, I did PPO and deployed it that Friday for @johnschulman2 to test. First prompt was tic-tac-toe, and it played surprisingly well. Time flies!

Jiayi Weng

@Trinkle23897

MTS @openai, author of the entire post-training RL infra, core contributor of ChatGPT/GPT4/GPT4o etc. 30U30

Joined June 2014

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Jiayi Weng@Trinkle23897

2025.08.07 18:12

As GPT-5 launches today, it's hard to forget the first ChatGPT-4 model called 0915-gpt4 internally at 2022. @shengjia_zhao did RM, I did PPO and deployed it that Friday for @johnschulman2 to test. First prompt was tic-tac-toe, and it played surprisingly well. Time flies!