Brockman Suggests o1/o3 and GPT-5 Are Built on GPT-4o

OpenAI President Greg Brockman appears to confirm that o1, o3, and GPT-5 variants are all built on the GPT-4o base model, noting the company has spent over a year squeezing more capability out of GPT-4o.

2026-09-03 ~ 2026-09-03 · 2 related posts

• Greg Brockman appears to confirm o1, o3 and GPT-5 all built on the GPT-4o base model — flowersslop · 2026-09-03
• Brockman Implies o1, o3, GPT-5 and GPT-5.1 All Built on the Same GPT-4o Base — scaling01 · 2026-09-03