Note
April 19, 2026
1 min read
A Tip I Picked Up Somewhere
By Cristiano Pierry
Bug fixes get sharper when agents start by reproducing the failure, then prove the fix with a passing test.

I do not remember where I first picked up this tip, but it has been extremely useful, especially when I am dealing with a bug that is hard to pin down:
“When I report a bug, do not start by trying to fix it. Start by writing a test that reproduces the bug. Then have subagents try to fix it and prove it with a passing test.”
That is exactly what Codex is doing for me right now on a particularly tricky mobile web issue:
- Add a Playwright regression that reproduces the mobile congratulations layout bug
- Have three workers independently fix the bug against the failing test
- Integrate the strongest fix locally and verify it with a passing test

Basically:
- Do not debate the bug. Reproduce it.
- Do not argue about the fix. Prove it.
This writing reflects my personal perspectives on product management, AI, and content discovery. It does not represent the official position of my employer or any affiliated organization.