Claude Opus 5 Jailbroken by Simple Prompt, Stuck in Infinite Repetition Loop

repligate · x · 2026-07-31

A user discovered a simple jailbreak prompt targeting Claude Opus 5. When used in incognito mode with a specific instruction, the model attempts to complete it like a base model but then gets stuck in an infinite loop, endlessly generating the same meaningless sentence.

This bizarre 'repetition loop' phenomenon has currently only been triggered on Opus 5 and Fable 5 models, with some chat sessions even being forcibly paused by the system. It highlights the ongoing fragility of large language models under certain edge-case conditions.

Related event: Specific Prompts Trigger Abnormal Completion and Jailbreak in Claude Opus(19 posts)→

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