Engineering article reviewResearch Insights Made Simple #35
Harness engineering: agent environments
Five months in which Codex wrote all of a product’s code while people built its environment
/ Research Insights Made Simple #35 · Harness engineering
Slide contents
1. Harness engineering: agent environments
Five months in which Codex wrote all of a product’s code while people built its environment
2. The coding ban became the method
3. Five months without hand-written code
4. Humans steer; agents write everything
5. Agent failures signal a missing capability
6. Human QA became the bottleneck
7. Every change boots its own app
8. Codex queries logs, metrics and traces
9. What Codex can’t see doesn’t exist
10. AGENTS.md is a table of contents
11. Repo knowledge is versioned and machine-checked
12. Domain layers are enforced mechanically
13. Lint errors tell the agent the fix
14. Enforce invariants, not implementations
15. One prompt: from bug to merge
16. At high throughput, fixing beats waiting
17. Pay down debt daily, not on Fridays
18. The numbers show scale, not cause
19. Five months observed; years remain open
20. Measure each environment capability you add
21. Count accepted tasks and human time
22. Discipline moves from code to scaffolding
23. Symphony moved coordination into issues
24. The experience became a draft specification