PrivacyLens
Language model agents write emails, posts or messages from a prior tool trajectory without leaking sensitive details. A judge scores information leakage and helpfulness.
Labs report the leakage rate over 493 prompts, where lower is better, often with a helpfulness score beside it.
- Made by
- Stanford University, Northeastern University and Harvard University
- Released
- August 2024
- Kind
- Refusing harmful requests
- Level
- Everyday
- Scored
- Graded by a model
- Answers
- Open-ended
- Tasks
- All public
- Strongest model tested
- Claude 3 Sonnet #186 on the capability index
- Last in a system card
- October 2026
- Last model added
- October 2026
- Scores refreshed
- November 12th, 2026
In the authors’ words
As language models (LMs) are widely utilized in personalized communication scenarios (e.g., sending emails, writing social media posts) and endowed with a certain level of agency, ensuring they act in accordance with the contextual privacy norms becomes increasingly critical. However, quantifying the privacy norm awareness of LMs and the emerging privacy risk in LM-mediated communication is challenging due to (1) the contextual and long-tailed nature of privacy-sensitive cases, and (2) the lack of evaluation approaches that capture realistic application scenarios. To address these challenges, we propose PrivacyLens, a novel framework designed to extend privacy-sensitive seeds into expressive vignettes and further into agent trajectories, enabling multi-level evaluation of privacy leakage in LM agents' actions. We instantiate PrivacyLens with a collection of privacy norms grounded in privacy literature and crowdsourced seeds. Using this dataset, we reveal a discrepancy between LM performance in answering probing questions and their actual behavior when executing user instructions in an agent setup. State-of-the-art LMs, like GPT-4 and Llama-3-70B, leak sensitive information in 25.68% and 38.69% of cases, even when prompted with privacy-enhancing instructions. We also demonstrate the dynamic nature of PrivacyLens by extending each seed into multiple trajectories to red-team LM privacy leakage risk. Dataset and code are available at https://github.com/SALT-NLP/PrivacyLens.
Muse Glimmer leads with 49.2%
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.
Zephyr 7B Beta leads with 19.3% 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.
Zephyr 7B Beta leads with 19.3%, 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.
- 1
Muse Glimmer 49.2%
Source: Labs’ model cards
Source: Official PrivacyLens leaderboard
- 1
Zephyr 7B Beta Privacy-Enhancing Prompt 19.3%
- 2
Mistral-7B-Instruct-v0.2 Basic Prompt 33.5%
- 3 Claude 3 Sonnet Privacy-Enhancing Prompt 37.3%
- 4 Claude 3 Haiku Basic Prompt 39%
- 5
Muse Glimmer 49.2%
Sources: Official PrivacyLens leaderboard and labs’ model cards
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 49.2% | Oct 2026 | Lab model card |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 19.3% | Privacy-Enhancing Prompt | Oct 2023 | Official leaderboard |
| 2 | | 33.5% | Basic Prompt | Dec 2023 | Official leaderboard |
| 3 | Claude 3 Sonnet | 37.3% | Privacy-Enhancing Prompt | Feb 2024 | Official leaderboard |
| 4 | Claude 3 Haiku | 39% | Basic Prompt | Mar 2024 | Official leaderboard |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 19.3% | Privacy-Enhancing Prompt | Oct 2023 | Official leaderboard |
| 2 | | 33.5% | Basic Prompt | Dec 2023 | Official leaderboard |
| 3 | Claude 3 Sonnet | 37.3% | Privacy-Enhancing Prompt | Feb 2024 | Official leaderboard |
| 4 | Claude 3 Haiku | 39% | Basic Prompt | Mar 2024 | Official leaderboard |
| 5 | | 49.2% | Oct 2026 | Lab model card |
The benchmark's own leaderboard has 9 entries, 4 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.
Source: Official PrivacyLens leaderboard
| Model | Effort | Harness | Score | Cost per task | Output tokens |
|---|---|---|---|---|---|
| Claude 3 Haiku | Basic Prompt | 39% | |||
| Claude 3 Haiku | Privacy-Enhancing Prompt | 39% | |||
| Claude 3 Sonnet | Basic Prompt | 38.3% | |||
| Claude 3 Sonnet | Privacy-Enhancing Prompt | 37.3% | |||
| | Privacy-Enhancing Prompt | 36.1% | |||
| | Basic Prompt | 33.5% | |||
| | Basic Prompt | 24.1% | |||
| | Privacy-Enhancing Prompt | 19.3% |
Number one over time 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.
Source: Official PrivacyLens leaderboard
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Sources: Official PrivacyLens leaderboard and labs’ model cards
Labs report it only in system cards
We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark. Some system cards do, below.
One system card reports it
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 |
|---|---|---|---|---|
| Oct 19, 2026 | | 49.2 | PrivacyLens leakage, lower is better, 493 prompts, high (Table 5) | Safety |
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%