Benchmark Almanac

CheatBench

Gemini 4 Argon 8.60% leads since Sep 2026 Not in model cards

Agents get hard assignments in environments that also offer ways to cheat, such as hidden answers, other agents' submissions or a manipulable grader. The score is the rate of cheating attempts, successful or not.

Ten categories, including math, coding, visual tasks and knowledge work. The site reports provider-harness and general-harness results for current frontier models. How attempts are labeled should be checked in the paper.

In the authors’ words

Reinforcement learning has helped AI agents solve increasingly difficult tasks, but high rewards do not always reflect the work users intended. In recent incidents and controlled evaluations across the AI industry, agents trained to maximize reward have accessed unauthorized information, attempted to evade monitoring systems, and even breached sandbox protections to attack external systems. As agents become more capable, this behavior could pose increasingly serious risks. To measure this problem, we introduce CheatBench, a benchmark of cheating in AI agents across mathematical research, knowledge work, coding, visual tasks, and other domains. Its environments combine challenging assignments with opportunities to cheat, allowing researchers to study how agents pursue a goal when honest work is difficult. CheatBench supports comparisons across models and task categories, providing a testbed for measuring and reducing cheating as agents take on more consequential responsibilities. We publicly release CheatBench at https://cheatbench.ai

Abstract of CheatBench: Measuring Reward Gaming in AI Agents (arXiv:2609.36308, CC0)
Made by Center for AI Safety Released Sep 2026 Deception and alignment Last model added Oct 2026 Scores refreshed 2 Nov 2026
Level
Expert Specialists with years of training, often over hours of work
Scored
Graded by a model A language model scores each response, usually against a rubric.
Answers
Agent task Many steps in a terminal, browser, desktop, app, game or robot.
10
Models scored on its own leaderboard

Gemini 4 Argon leads with 8.60%

Best score per model from the benchmark's own leaderboard, read on 2 Nov 2026. Where a model ran with several settings or harnesses, we keep its best.

  1. 1 Gemini 4 Argon 8.60%
  2. 2 Claude Opus 5.5 11.2%
  3. 3 Muse Wonder 12.7%
  4. 4 Claude Fable 5.1 45.8%
  5. 5 GPT-6 Astra 47.4%
  6. 6 GPT-6.1 Sol 49.3%
  7. 7 Kimi K3 70%
  8. 8 DeepSeek-V4-Pro 75.1%
  9. 9 Grok 4.7 78%
  10. 10 Muse Spark Open 84.2%
#ModelScoreSettingDateSource
1 Gemini 4 Argon 8.60% Sep 2026 Official leaderboard
2 Claude Opus 5.5 11.2% Sep 2026 Official leaderboard
3 Muse Wonder 12.7% Oct 2026 Official leaderboard
4 Claude Fable 5.1 45.8% Sep 2026 Official leaderboard
5 GPT-6 Astra 47.4% Sep 2026 Official leaderboard
6 GPT-6.1 Sol 49.3% Sep 2026 Official leaderboard
7 Kimi K3 70% Jul 2026 Official leaderboard
8 DeepSeek-V4-Pro 75.1% Apr 2026 Official leaderboard
9 Grok 4.7 78% Sep 2026 Official leaderboard
10 Muse Spark Open 84.2% Oct 2026 Official leaderboard

3 models have held number one since its release in Sep 2026

Lab claims count from the day the card came out, independent runs from the model’s release.

Anthropic Google DeepMind
Own leaderboard 3 leaders

Scores over time

All the scores we have, one dot each, so a model tested at several settings appears more than once.

On the benchmark’s own leaderboard Best so far
0% 20% 40% 60% 80% 100% 2026 Gemini 4 Argon Claude Fable 5.1 Kimi K3 DeepSeek-V4-Pro 0% 20% 40% 60% 80% 100% 2026 Gemini 4 Argon Claude Fable 5.1

No lab model card reports it yet

We read the headline results of 479 launch posts from 51 labs, and none of them list this benchmark.

More in Safety and alignment

All 444 in Safety and alignment
  • FORTRESS In use Paired adversarial and benign national-security misuse prompts. Rubric-graded risk score on adversarial and over-refusal score on benign prompts. Claude Opus 5.5 5.78%
  • StrongREJECT In use Forbidden-prompt jailbreak benchmark with a rubric grader that scores how useful a non-refusal actually is. Inkling 98.6%
  • AgentDojo In use Agents do tool-use tasks while tools and data carry prompt injections. Attack success rate counts hijacked runs. Grok 4 Fast 0%
  • MASK In use Measures whether a model contradicts its own elicited beliefs under pressure to lie. Honesty separated from accuracy. Muse Spark Open 98.1%
  • Gray Swan IPI Arena benchmark In use Indirect prompt-injection attacks from public red-teaming competitions replayed on tool, coding and browser agents. Attack success rate at k attempts. GPT-6 Astra 8.50%
  • Agentic misalignment suite (Anthropic) In use Agents in simulated company settings face threats or goal conflicts that invite blackmail, leaking or sabotage. Score is the misaligned action rate. Claude Sonnet 4.5 0%