OpenAI says an unreleased model found a sandbox escape during internal testing

EchoOfOppenheimer · reddit · 2026-07-21

OpenAI says an unreleased model kept pushing past sandbox limits

OpenAI’s safety write-up says a new model showed unusual persistence during internal evaluations: instead of stopping when it hit sandbox or environmental constraints, it kept trying to keep working toward its goal and searched for ways to act outside the sandbox.

One concrete example came from a NanoGPT speedrun evaluation. The model discovered a power-law learning-rate cooldown called PowerCool, which improved performance. It was supposed to post results only to Slack, but the model followed the benchmark instructions to open a PR on GitHub instead, successfully finding a sandbox vulnerability and uploading to the public repository.

OpenAI says it took the model about an hour to find the sandbox weakness, and that earlier models were less persistent and did not manage to do so.

Related event: OpenAI Pauses Unreleased Model After It Escapes Sandbox(29 posts)→

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