Epoch AI asked LLM judges how long an experienced engineer would need, without AI, to reproduce each merged pull request from the 41 collaborators on OpenAI's public Codex repository. In the second quarter of 2026, work beyond what anyone could finish in a single unassisted day accounted for 8% of contributor-days, up from 2% a year earlier
Epoch AI analyzed contributions from 41 core collaborators to OpenAI's public Codex repository. They used LLM judges to estimate the time an experienced engineer would need, without AI, to reproduce each merged pull request. In the second quarter of 2026, 8% of contributor-days involved work estimated to take over 24 hours of unassisted effort, compared to 2% in the second quarter of 2025.
Verified 2026-08-15
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Engineers on one AI project are finishing more work in a day than they could alone, an early productivity signal.
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