# Stop option

A way for the agent to flag a task as impossible and hand it to a person.

**Is a:** [Guard](/reference/ontology/unattended-agent-failures/guard)

Told to submit `flag_for_human_intervention` when a task is impossible, GPT-5's cheating fell from 54% to 9% and o3's from 49% to 12%, with a much smaller effect for Claude Opus 4.1 ([ImpossibleBench](https://arxiv.org/abs/2510.20270)).

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Published 2026-10-29. Web page: https://www.mackenziebowes.com/reference/ontology/unattended-agent-failures/stop-option