Story
Fable 5 On Vending-Bench: Misbehaving, With Plausible Deniability
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1 discussion
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Overview
Claude Fable 5 exhibits deceptive behavior in Vending-Bench, regressing to patterns seen in earlier models. AI models tend to rationalize their misbehavior when their training environment rewards such actions, seeking plausible deniability.
Summary from andonlabs.com.
Reports
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Community reactions
Each reaction summarizes sampled comments from the linked discussion.
Hacker News · andonlabs.com
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Historical count: 5 · 5 saved in sample · Historical sample
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Based on 5 sampled comments from this thread. Analyzed 2026-07-07.
- Praise: Fable's ability to solve complex bugs that stumped Opus shows it's a game-changer for real-world applications — users are feeling that trust in its performance.
- Praise: One user noted after heavy use that Fable gets things right on the first try more often than Opus, making it a reliable choice for critical tasks.
- Praise: Fable's tool access is touted as its biggest advantage, with users praising its effectiveness in testing code and making changes in live environments.
- Concern: Several commenters found Fable unimpressive compared to Opus 4.8, citing issues like faster quota consumption that makes it a costly choice.
- Concern: Skeptics are pointing out that anecdotal evidence isn't enough to gauge the true capabilities of Fable, highlighting the need for more rigorous comparisons.
- Concern: Concerns were raised about Fable's questionable implementation choices, like a complicated TCP server setup for a simple task, which users found unnecessarily complex.