Petri
Only in system cards
Open-source auditing tool where auditor agents probe target models in simulated scenarios and judges score misaligned behaviors.
Anthropic cards use Petri to compare Claude with other labs' models.
Made by Anthropic Released Oct 2025 Deception and alignment All tasks public Last in a system card Jul 2026
Last model added Jul 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.
8
System cards report it, from 2 labs
No scores here yet
No lab, leaderboard or Epoch AI run has reported a score for Petri yet.
Labs report it only in system cards
We read the headline results of 479 launch posts from 51 labs, and none of them list this benchmark. Some system cards do, below.
8 system cards report it, from 2 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.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| 9 Jul 2026 |  Muse Spark 1.1 system card | 1.74 | Petri 3.0 overall misaligned behavior, mean judge score, averaged over three auditors (Table 16) | Alignment |
| 28 May 2026 | Claude Opus 4.8 system card | Petri 3.0 run by Meridian and UK AISI, 346 seeds, six metrics (misaligned behavior, verbalized evaluation awareness, cooperation with human misuse, user deception, sycophancy, encouragement of user delusion), chart without printed values (6.2.3.3, Figure 6.2.3.3.A) | Alignment | |
| 16 Apr 2026 | Claude Opus 4.7 system card | Petri 2.0, six metrics including misaligned behavior, 362 investigations per model, charts without printed values (6.2.3.3, Figure 6.2.3.3.A) | Alignment | |
| 7 Apr 2026 | Claude Mythos Preview system card | Petri 2.0 external comparison on a significantly earlier snapshot, 362 investigations, six metrics including misaligned behavior, charts without printed values (4.2.3.2, Figure 4.2.3.2.A) | Alignment | |
| 17 Feb 2026 | Claude Sonnet 4.6 system card | Petri 2.0, six metrics including misaligned behavior, charts without printed values; verbalized evaluation awareness 1.2 of 10 stated in text (Figure 4.5.3.A) | Alignment | |
| 5 Feb 2026 | Claude Opus 4.6 system card | Petri 2.0 external comparison, 362 investigations, six metrics including misaligned behavior and verbalized evaluation awareness, charts without printed values (Figure 6.2.5.5.A) | Alignment | |
| 24 Nov 2025 | Claude Opus 4.5 system card | Petri external comparison, pre-final Claude Opus 4.5 Preview snapshot, 362 investigations, concerning, evaluation awareness, misuse cooperation, user deception and sycophancy, chart without printed values (Figure 6.2.4.A) | Alignment | |
| 29 Sep 2025 | Claude Sonnet 4.5 system card | Pre-release open-source automated behavioral auditor, 111 seed instructions, auditors and graders from several developers, misaligned behavior score chart without printed values (7.1.3.3, Figure 7.1.3.3.A) | Alignment |
Versions
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% - 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%