Harness engineering: leveraging Codex in an agent-first world

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Harness engineering: leveraging Codex in an agent-first world | OpenAI

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Related to

The Last Harness Youll Ever Build arXiv OpenAI's Codex harness-engineering piece and the arXiv 'Last Harness' paper both argue that the scaffolding around a model is the key lasting artifact in agentic coding.

Schema: Frontier Models with the Right Harness Achieve ~99% on ARC-AGI-3 Public Both discuss how the surrounding harness/environment interface, not raw model power, determines agent performance on complex tasks.

Type:	link
First published:	Thursday, 30 April 2026 at 12:00 UTC
Location:	https://openai.com/index/harness-engineering/
URL:	https://mattwood.fyi/i/18baadd9