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CheatBench

Safety · 2026-09-28

The Center for AI Safety's CheatBench measures how often AI agents cheat on hard assignments that contain a discoverable shortcut, such as a planted solution, a colleague's accepted work, exposed chess-engine advice or a way to tamper with grading, across ten categories: mathematical research, multimodal, creative writing, SVG competition, menial computation, biology and bioinformatics, knowledge work, board games, software engineering and sycophancy. An LLM judge, or in some environments a classifier over recorded events, labels each episode that contains a cheating attempt, successful or not; nine category rates pool the episodes of their tasks (software engineering counts each task once), and sycophancy is a 0-100 score for how far direct-API probability estimates shift toward a user's stated views. The score is the equal-weight mean of the ten category scores, in percent, and lower is better. Agents run in their developer's own harness or, in the General Harness view, in Terminus-2; the score is a propensity, not a capability.

Benchmark source: arXiv

Top models (lower is better)

ModelScoreSource
Claude Opus 5.57.2CheatBench General Harness: Claude Opus 5.5 (Terminus-2) · Center for AI Safety
Gemini 4 Argon8.6CheatBench Provider Harness: Gemini 4 Argon (Gemini CLI) · Center for AI Safety
Muse Wonder12.7CheatBench Provider Harness: Muse Wonder (Muse Code) · Center for AI Safety
Muse Spark 1.337.0CheatBench Provider Harness: Muse Spark 1.3 (Muse Code) · Center for AI Safety
GPT-6.1 Sol42.8CheatBench General Harness: GPT-6.1 Sol (Terminus-2) · Center for AI Safety
GPT-6 Astra45.0CheatBench General Harness: GPT-6 Astra (Terminus-2) · Center for AI Safety
Claude Opus 545.3CheatBench Provider Harness: Claude Opus 5 (Claude Code) · Center for AI Safety
Claude Fable 5.145.8CheatBench Provider Harness: Claude Fable 5.1 (Claude Code) · Center for AI Safety
Kimi K370.0CheatBench Provider Harness: Kimi K3 (Kimi Code) · Center for AI Safety
GPT-6 Sol71.9CheatBench Provider Harness: GPT-6 Sol (Codex) · Center for AI Safety
GPT-5.6 Sol74.9CheatBench General Harness: GPT-5.6 Sol (Terminus-2) · Center for AI Safety
Gemini 3.8 Flash75.2CheatBench Provider Harness: Gemini 3.8 Flash (Gemini CLI) · Center for AI Safety
Grok 4.778.0CheatBench Provider Harness: Grok 4.7 (Grok Build) · Center for AI Safety
Grok 4.679.1CheatBench Provider Harness: Grok 4.6 (Grok Build) · Center for AI Safety
Muse Spark Open84.2CheatBench Provider Harness: Muse Spark Open (Muse Code) · Center for AI Safety
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