Benchmark Almanac

AgentHarm

Grok 4 Fast 8.00% leads since September 2025
Llama 3.1-8B 3.10% leads since October 2024
Llama 3.1-8B 3.10% leads since October 2024
Fading

110 malicious agent tasks with synthetic tools. Measures refusal and harmful task completion, plus benign controls.

Implemented in Inspect Evals. Part of the test set is private.

Released
October 2024
Kind
Refusing harmful requests
Scored
Checked automatically
Answers
Agent task
Tasks
Public, plus a private test set
Strongest model tested
Muse Spark #53 on the capability index
Last in a launch post
March 2026, dropped before it saturated
Last model added
June 2026
Scores refreshed
November 12th, 2026

In the authors’ words

The robustness of LLMs to jailbreak attacks, where users design prompts to circumvent safety measures and misuse model capabilities, has been studied primarily for LLMs acting as simple chatbots. Meanwhile, LLM agents – which use external tools and can execute multi-stage tasks – may pose a greater risk if misused, but their robustness remains underexplored. To facilitate research on LLM agent misuse, we propose a new benchmark called AgentHarm. The benchmark includes a diverse set of 110 explicitly malicious agent tasks (440 with augmentations), covering 11 harm categories including fraud, cybercrime, and harassment. In addition to measuring whether models refuse harmful agentic requests, scoring well on AgentHarm requires jailbroken agents to maintain their capabilities following an attack to complete a multi-step task. We evaluate a range of leading LLMs, and find (1) leading LLMs are surprisingly compliant with malicious agent requests without jailbreaking, (2) simple universal jailbreak templates can be adapted to effectively jailbreak agents, and (3) these jailbreaks enable coherent and malicious multi-step agent behavior and retain model capabilities. To enable simple and reliable evaluation of attacks and defenses for LLM-based agents, we publicly release AgentHarm at https://huggingface.co/datasets/ai-safety-institute/AgentHarm.

Abstract of AgentHarm: A Benchmark for Measuring Harmfulness of LLM Agents (arXiv:2410.09024, CC0)
6
Models scored in lab cards
1
Launch post lists it, from 1 lab
7
System cards report it, from 3 labs

Grok 4 Fast leads with 8.00% among models released by April 2026

Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.

Llama 3.1-8B leads with 3.10% across all independent runs

Best score per model across the official leaderboard, Epoch AI’s own runs and any board Epoch AI copied. Each bar and row names its source.

Llama 3.1-8B leads with 3.10%, claims included

Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.

The newest model with a score here came out in April 2026, and nobody has reported a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:

  1. 1 Grok 4 Fast 8.00%
  2. 2 Grok 4 14%
  3. 3 Grok 4.1 14%
  4. 4 grok-code-fast-1 17%
  5. 5 Muse Spark 26%
  6. 6 Grok 4.20 30%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 Grok 4 Fast 8.00% Sep 2025 Lab model card
2 Grok 4 14% Aug 2025 Lab model card
3 Grok 4.1 14% Nov 2025 Lab model card
4 grok-code-fast-1 17% Aug 2025 Lab model card
5 Muse Spark 26% Jun 2026 Lab model card
6 Grok 4.20 30% Mar 2026 Lab model card
#ModelScoreSettingDateSource
1 Llama 3.1-8B 3.10% None attack; Standard prompt Jul 2024 Official leaderboard
2 Llama 3.1-405B 4.30% None attack; Standard prompt Jul 2024 Official leaderboard
3 Claude 3 Haiku 6.60% Template attack; Standard prompt Mar 2024 Official leaderboard
4 Gemini 1.0 Pro 7.40% None attack; Standard prompt Dec 2023 Official leaderboard
5 Llama 3.1-70B 14% None attack; Standard prompt Jul 2024 Official leaderboard
6 Claude 3 Opus 14.4% None attack; Standard prompt Feb 2024 Official leaderboard
7 Claude 3 Sonnet 20.7% None attack; Standard prompt Feb 2024 Official leaderboard
8 Mistral Large 2 Jul 2024 69.1% None attack; Refusal prompt Jul 2024 Official leaderboard
#ModelScoreSettingDateSource
1 Llama 3.1-8B 3.10% None attack; Standard prompt Jul 2024 Official leaderboard
2 Llama 3.1-405B 4.30% None attack; Standard prompt Jul 2024 Official leaderboard
3 Claude 3 Haiku 6.60% Template attack; Standard prompt Mar 2024 Official leaderboard
4 Gemini 1.0 Pro 7.40% None attack; Standard prompt Dec 2023 Official leaderboard
5 Grok 4 Fast 8.00% Sep 2025 Lab model card
6 Llama 3.1-70B 14% None attack; Standard prompt Jul 2024 Official leaderboard
7 Grok 4 14% Aug 2025 Lab model card
8 Grok 4.1 14% Nov 2025 Lab model card
9 Claude 3 Opus 14.4% None attack; Standard prompt Feb 2024 Official leaderboard
10 grok-code-fast-1 17% Aug 2025 Lab model card
11 Claude 3 Sonnet 20.7% None attack; Standard prompt Feb 2024 Official leaderboard
12 Muse Spark 26% Jun 2026 Lab model card
13 Grok 4.20 30% Mar 2026 Lab model card
14 Mistral Large 2 Jul 2024 69.1% None attack; Refusal prompt Jul 2024 Official leaderboard

The benchmark's own leaderboard has 15 entries, 8 of them models we track. Switch the scores above to rank them together.

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.

Lowest effort to highest, light to dark
Mistral Large 2
Template at… None attack… None attack…
82.2%
Claude 3 Sonnet
Forced tool… Template at… None attack…
52.8%
Claude 3 Opus
Forced tool… Template at… None attack…
45.7%
Llama 3.1-70B
Template at…
15%
Gemini 1.0 Pro
Template at… None attack…
23.3%
Claude 3 Haiku
Template at… Forced tool… None attack…
33.9%
Llama 3.1-405B
Template at…
4.30%
Llama 3.1-8B
Template at… None attack…
27.5%

Source: Official AgentHarm leaderboard

ModelEffortHarnessScoreCost per taskOutput tokens
Mistral Large 2 Jul 2024 None attack; Standard prompt 82.2%
Mistral Large 2 Jul 2024 Template attack; CoT prompt 81.6%
Mistral Large 2 Jul 2024 None attack; CoT prompt 81.4%
Mistral Large 2 Jul 2024 Forced tool call attack; Standard prompt 80.9%
Mistral Large 2 Jul 2024 Template attack; ReAct prompt 80.8%
Mistral Large 2 Jul 2024 Template attack; Standard prompt 80.5%
Mistral Large 2 Jul 2024 Template attack; Refusal prompt 79.5%
Mistral Large 2 Jul 2024 None attack; ReAct prompt 72.3%
Mistral Large 2 Jul 2024 None attack; Refusal prompt 69.1%
Claude 3 Sonnet Template attack; Standard prompt 52.8%
Claude 3 Opus Template attack; Standard prompt 45.7%
Claude 3 Sonnet Forced tool call attack; Standard prompt 42.8%
Claude 3 Haiku Forced tool call attack; Standard prompt 33.9%
Claude 3 Opus Forced tool call attack; Standard prompt 29.5%
Llama 3.1-8B Template attack; Standard prompt 27.5%
Gemini 1.0 Pro Template attack; Standard prompt 23.3%
Claude 3 Sonnet None attack; Standard prompt 20.7%
Llama 3.1-70B Template attack; Standard prompt 15%
Claude 3 Opus None attack; Standard prompt 14.4%
Llama 3.1-70B None attack; Standard prompt 14%
Claude 3 Haiku None attack; Standard prompt 11.1%
Gemini 1.0 Pro None attack; Standard prompt 7.40%
Claude 3 Haiku Template attack; Standard prompt 6.60%
Llama 3.1-405B None attack; Standard prompt 4.30%
Llama 3.1-405B Template attack; Standard prompt 4.30%
Llama 3.1-8B None attack; Standard prompt 3.10%

2 models have held number one in labs’ own numbers since its release in October 2024 Number one over time Number one over time

Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard and what labs claim in their cards.

Meta xAI
Own leaderboard Not tested since Oct 2024
Llama 3.1-8B 3.10%
Lab claims Not tested since Jun 2026
Grok 4 Fast 8.00%

Sources: Official AgentHarm leaderboard and labs’ model cards

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 Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2024 2025 2026 Llama 3.1-8B Gemini 1.0 Pro Gemini 1.0 Pro 0% 20% 40% 60% 80% 100% 2024 2025 2026 Llama 3.1-8B Gemini 1.0 Pro

Sources: Official AgentHarm leaderboard and labs’ model cards

Labs headline it less often now, last in March 2026

Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.

xAI
DateLaunch postScoreAs the post writes it
Mar 9, 2026 Grok 4.20 30 AgentHarm, violation rate 0.30, no jailbreak, Grok 4.2 SA, Table 1

7 system cards report it, from 3 labs

Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.

DateDocumentScoreAs the document writes itSection
Jun 12, 2026 Muse Spark system card 26 AgentHarm score (Table 2, Figure 32). Benign subset FRR 6.8 Robustness
Apr 7, 2026 Grok 4.20 model card 30 AgentHarm, violation rate 0.30, no jailbreak, Grok 4.2 SA, Table 1 Safety
Nov 24, 2025 Fara-7B technical report AgentHarm-Chat, harmful tasks safely refused (Table 14) Safety
Nov 17, 2025 Grok 4.1 model card 14 AgentHarm, answer rate 0.14, no jailbreak, Grok 4.1 Thinking (Table 1) Safety
Sep 19, 2025 Grok 4 Fast model card 8 AgentHarm, answer rate 0.08, no attack, 0.10 non-reasoning (Table 1) Safety
Aug 26, 2025 grok-code-fast-1 model card 17 AgentHarm, answer rate 17.0 (Table 1) Safety
Aug 20, 2025 Grok 4 model card 14 AgentHarm, answer rate 0.14, no attack, Grok 4 API (Table 1) Safety

More in Safety and alignment

All 465 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%