Definition
Plain language
Re-running your existing checks after a change to make sure you didn't break something that used to work.
As stated in the literature
A test verifying that previously-working behavior still holds after a code change; RHO and HarnessFix accept a harness edit only if it improves the target metric without breaking more than a tolerated number of already-passing tasks (regression-aware acceptance).
Also called: regression-aware, regression testing
Why it matters: It guards against the common trap of fixing one thing while silently breaking another.
For example, after fixing a bug in the login page, a team re-runs its existing tests to confirm the checkout page still works as it did before.
Heard on the show
“As the authors put it, regression-aware acceptance is what turns useful candidates into safe-to-accept changes.”Episode 121 — When the Agent Says It's Done But Nothing Happened: Debugging the Harness, Not the Model