BrowserART
Browser agents receive 100 harmful requests on synthetic and real websites. The test measures how often the agent attempts the harmful behavior that its backbone model would refuse in chat.
Some behaviors come from HarmBench and AIR-Bench 2024. Chat jailbreak methods transferred well to browser agents in the paper.
- Made by
- Scale AI and collaborators
- Released
- October 2024
- Kind
- Refusing harmful requests
- Level
- Expert
- Scored
- Graded by a model
- Answers
- Agent task
- Tasks
- All public
- Strongest model tested
- o1-mini #140 on the capability index
- Last model added
- September 2024
- Scores refreshed
- November 12th, 2026
In the authors’ words
For safety reasons, large language models (LLMs) are trained to refuse harmful user instructions, such as assisting dangerous activities. We study an open question in this work: does the desired safety refusal, typically enforced in chat contexts, generalize to non-chat and agentic use cases? Unlike chatbots, LLM agents equipped with general-purpose tools, such as web browsers and mobile devices, can directly influence the real world, making it even more crucial to refuse harmful instructions. In this work, we primarily focus on red-teaming browser agents, LLMs that manipulate information via web browsers. To this end, we introduce Browser Agent Red teaming Toolkit (BrowserART), a comprehensive test suite designed specifically for red-teaming browser agents. BrowserART is consist of 100 diverse browser-related harmful behaviors (including original behaviors and ones sourced from HarmBench [Mazeika et al., 2024] and AirBench 2024 [Zeng et al., 2024b]) across both synthetic and real websites. Our empirical study on state-of-the-art browser agents reveals that, while the backbone LLM refuses harmful instructions as a chatbot, the corresponding agent does not. Moreover, attack methods designed to jailbreak refusal-trained LLMs in the chat settings transfer effectively to browser agents. With human rewrites, GPT-4o and o1-preview-based browser agents attempted 98 and 63 harmful behaviors (out of 100), respectively. We publicly release BrowserART and call on LLM developers, policymakers, and agent developers to collaborate on improving agent safety
Llama-3.1-405B-Instruct tops the leaderboard with 10%
Best score per entry from the benchmark's own leaderboard, read on November 12th, 2026. Where a model ran with several settings or harnesses, we keep its best. Every run is in the next chart. Names in gray aren't in our model list: fine-tunes, agent systems, products and older models. They don't count toward leaders. The best model we track is Claude 3 Opus, at 11%.
The newest model with a score here came out in September 2024, and nobody has tested a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:
- Claude Fable 5.2
-
Gemini 4 Carbon
- GPT-6 Astra
- Claude Opus 5.5
- and 16 more
- 1 Llama-3.1-405B-Instruct DA 10%
- 2 Claude 3 Opus DA 11%
- 3 o1-preview DA 13%
- 4 Claude 3.5 Sonnet DA 22%
- 5 o1-mini DA 24%
- 6 gemini-1.5-pro-001 DA 25%
- 7 GPT-4 Turbo Apr 2024, DA 67%
- 8 GPT-4o Aug 2024, DA 74%
Source: Official BrowserART leaderboard
| # | Entry | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | Llama-3.1-405B-Instruct | 10% | DA, BrowserART browser agent | Official leaderboard | |
| 2 | Claude 3 Opus | 11% | DA, BrowserART browser agent | Feb 2024 | Official leaderboard |
| 3 | o1-preview | 13% | DA, BrowserART browser agent | Sep 2024 | Official leaderboard |
| 4 | Claude 3.5 Sonnet | 22% | DA, BrowserART browser agent | Jun 2024 | Official leaderboard |
| 5 | o1-mini | 24% | DA, BrowserART browser agent | Sep 2024 | Official leaderboard |
| 6 | gemini-1.5-pro-001 | 25% | DA, BrowserART browser agent | Official leaderboard | |
| 7 | GPT-4 Turbo Apr 2024 | 67% | DA, BrowserART browser agent | Apr 2024 | Official leaderboard |
| 8 | GPT-4o Aug 2024 | 74% | DA, BrowserART browser agent | Aug 2024 | Official leaderboard |
Scores at each effort level
Models the leaderboard ran at two or more effort levels. We don’t have enough cost data here to say what the extra effort costs.
Source: Official BrowserART leaderboard
| Model | Effort | Harness | Score | Cost per task | Output tokens |
|---|---|---|---|---|---|
| GPT-4 Turbo Apr 2024 | Ensemble | BrowserART browser agent | 100% | ||
| GPT-4o Aug 2024 | Ensemble | BrowserART browser agent | 100% | ||
| GPT-4 Turbo Apr 2024 | + Human | BrowserART browser agent | 99% | ||
| GPT-4o Aug 2024 | + Human | BrowserART browser agent | 98% | ||
| GPT-4 Turbo Apr 2024 | + Prefix | BrowserART browser agent | 95% | ||
| GPT-4o Aug 2024 | + Prefix | BrowserART browser agent | 94% | ||
| GPT-4o Aug 2024 | + GCG | BrowserART browser agent | 89% | ||
| o1-mini | Ensemble | BrowserART browser agent | 87% | ||
| GPT-4 Turbo Apr 2024 | + GCG | BrowserART browser agent | 85% | ||
| o1-mini | + Human | BrowserART browser agent | 84% | ||
| GPT-4o Aug 2024 | + RS | BrowserART browser agent | 82% | ||
| Claude 3.5 Sonnet | Ensemble | BrowserART browser agent | 75% | ||
| GPT-4 Turbo Apr 2024 | + RS | BrowserART browser agent | 74% | ||
| GPT-4o Aug 2024 | DA | BrowserART browser agent | 74% | ||
| Claude 3.5 Sonnet | + Human | BrowserART browser agent | 70% | ||
| GPT-4 Turbo Apr 2024 | DA | BrowserART browser agent | 67% | ||
| o1-preview | Ensemble | BrowserART browser agent | 66% | ||
| o1-preview | + Human | BrowserART browser agent | 63% | ||
| Claude 3 Opus | Ensemble | BrowserART browser agent | 41% | ||
| Claude 3 Opus | + Human | BrowserART browser agent | 40% | ||
| Claude 3.5 Sonnet | + Prefix | BrowserART browser agent | 37% | ||
| o1-mini | + GCG | BrowserART browser agent | 35% | ||
| Claude 3.5 Sonnet | + GCG | BrowserART browser agent | 30% | ||
| o1-mini | + RS | BrowserART browser agent | 30% | ||
| o1-mini | + Prefix | BrowserART browser agent | 25% | ||
| o1-mini | DA | BrowserART browser agent | 24% | ||
| Claude 3.5 Sonnet | DA | BrowserART browser agent | 22% | ||
| Claude 3.5 Sonnet | + RS | BrowserART browser agent | 22% | ||
| o1-preview | + RS | BrowserART browser agent | 21% | ||
| o1-preview | + GCG | BrowserART browser agent | 20% | ||
| o1-preview | + Prefix | BrowserART browser agent | 18% | ||
| Claude 3 Opus | + GCG | BrowserART browser agent | 14% | ||
| o1-preview | DA | BrowserART browser agent | 13% | ||
| Claude 3 Opus | + RS | BrowserART browser agent | 12% | ||
| Claude 3 Opus | DA | BrowserART browser agent | 11% | ||
| Claude 3 Opus | + Prefix | BrowserART browser agent | 11% |
Number one over time
Lab claims count from the day the card came out, independent runs from the model’s release.
Source: Official BrowserART leaderboard
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Source: Official BrowserART leaderboard
No lab model card reports it yet
We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark.
More 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%
- 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.
Gemini 4 Carbon 0%
- DistressBench In use Models reply as a chatbot to 718 simulated users in psychological crisis, in single-turn and multi-turn chats. Three judge models score replies against clinician-written rubrics.
Muse Spark 1.2 88.4%
- Lakera B3 (Backbone Breaker Benchmark) In use Crowdsourced prompt-injection attacks hit backbone LLMs inside agent threat snapshots at three defense levels. The score is attack resistance, 100 minus the board's vulnerability percentage. Claude Opus 4.5 89%
- IHEval In use Models face conflicts between system, user and tool instructions. Reports a composite score for following the higher-priority instruction. GPT-4o 70%