Your Team's Benchmarks Are Lying to Each Other: Shared Eval Infrastructure Contamination
Your red team just finished a jailbreak sweep. They found three novel attack vectors, wrote them up, and dropped the prompts into your shared prompt library for others to learn from. The next week, the safety team runs their baseline evaluation and reports a 12% improvement in robustness. Everyone celebrates. Nobody asks why.
What actually happened: the safety team's baseline eval silently incorporated the red team's attack prompts. The model didn't get more robust — the eval got contaminated. Your benchmarks are now measuring inoculation against known attacks, not generalization to new ones.
This is shared eval infrastructure contamination, and it is far more common than most teams realize. The symptom is artificially inflating metrics. The cause is treating evaluation infrastructure like production infrastructure — optimized for sharing and efficiency, instead of isolation and fidelity.
