The instruction file next to the work it governed

In OpenAI's experiment the standing instructions were kept deliberately tiny. Everything else that the tool needed to know was written down separately, and kept where the work was. Note the scale below: each step along the axis is ten times the one before it.

3 to 7

People on the team. Output per person rose as it grew, rather than falling.

1,500

Separate changes made and accepted over five months.

1 day in 5

Spent tidying up by hand, until the standards were built into automatic checks instead.

Source: Ryan Lopopolo, "Harness engineering: leveraging Codex in an agent-first world", OpenAI, February 2026. Figures as reported. Line counts are approximate and stated by the author as being of that order.