Stress-testing model specs reveals character differences among language models
We generate over 300,000 user queries that trade-off value-based principles in model specifications. Under these scenarios, we observe distinct value prioritization and behavior patterns in frontier models from Anthropic, OpenAI, Google DeepMind and xAI. Our experiments also uncovered thousands of cases of direct contradictions or interpretive ambiguities within the model spec. 📄 Paper, 📊 Dataset Model specifications are the behavioral guidelines that large language models are trained to follow. They list principles like "be helpful," "assume good intentions," or "stay within safety bounds." Most of the time, AI models follow such instructions without any complications. But what happens when these principles clash? Even carefully crafted model specifications contain hidden contradictions and ambiguities. In a new paper, led by participants in the Anthropic Fellows program and in collaboration with researchers at the Thinking Machines Lab, we expose these ‘specification gaps’ by gener
Stress-testing model specs reveals character differences among language models Alignment Science Blog Stress-testing model specs reveals character differences among language models Jifan Zhang 1 , Henry Sleight 2 , Andi Peng 3 , John Schulman 4 , Esin Durmus 3 October 24, 2025 1 Anthropic Fellows Program; 2 Constellation; 3 Anthropic; 4 Thinking Machines tl;dr We generate over 300,000 user queries that trade-off value-based principles in model specifications. Under these scenarios, we observe distinct value prioritization and behavior patterns in frontier models from Anthropic, OpenAI, Google
related reading
- Agentic misalignment: How LLMs could be insider threats \ Anthropicanthropic.com
- Teaching Claude Whyalignment.anthropic.com
- How confessions can keep language models honest | OpenAIopenai.com
- Automated Alignment Researchers: Using large language models to scale scalable oversight \ Anthropicanthropic.com
- [2605.24229] How Well Do Models Follow Their Constitutions?arxiv.org
- [2607.14345] Value Leakage: An LLM's Answers Are Silently Shaped by Its Own Valuesarxiv.org
- [2510.07686] Stress-Testing Model Specs Reveals Character Differences among Language Modelsarxiv.org
- User awareness in frontier modelstransluce.org
- Model Spec Midtraining: Improving How Alignment Training Generalizesalignment.anthropic.com
- Discovering Language Model Behaviors with Model-Written Evaluations — LessWronglesswrong.com
- How Claude's values vary by model and language \ Anthropicanthropic.com
- Self-Fulfilling Misalignment Data Might Be Poisoning Our AI Modelsturntrout.com