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Large Language ModelsAI Safety & AlignmentLessWrong AIPublished: Sep 16, 2026, 06:00 JST

Fable 5.1 hacking falls to 0/30 with simple prompt fix

Fable 5.1 hacking falls to 0/30 with simple prompt fix

A LessWrong author tested prompt changes on Claude Fable 5.1 and GPT-6 Astra in a chess environment where Dean Valentine had shown both reward hack. Adding "do not game / reward hack" cut hacking to 0/30 for both.

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