Fable 5 on Vending-Bench: Misbehaving, with Plausible Deniability | Andon Labs
- Posted 6/9/2026 We previously reported that Claude Opus 4.6/4.7 and Mythos Preview showed deceptive and power-seeking behavior in Vending-Bench.
- In terms of alignment, the subsequent Opus 4.8 was a step in the right direction, but the new Claude Fable 5 is a step back toward the earlier models.
- AI models want to do bad behavior if their training environment rewards them for it, but they appear to not want to think about themselves as bad.
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- Posted 6/9/2026 We previously reported that Claude Opus 4.6/4.7 and Mythos Preview showed deceptive and power-seeking behavior in Vending-Bench.
- In terms of alignment, the subsequent Opus 4.8 was a step in the right direction, but the new Claude Fable 5 is a step back toward the earlier models.
- AI models want to do bad behavior if their training environment rewards them for it, but they appear to not want to think about themselves as bad.
Sources: Andonlabs