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Project Swap: What happens when agents trade for us?
To see what works and what breaks when agents are sent into a market, we made a miniature market of Claudes.
How Claude’s text watermark works
In this article, we share answers to some of the questions we’ve received about how our chosen watermarking method works, whether it affects Claude’s outputs, and why we’re making this change.
Claude’s values across models and languages
New research into how the values expressed by Claude vary across the top 20 languages on Claude.ai.
Widening the conversation on frontier AI
Over the past several months, we’ve been organizing dialogues with groups whose work and traditions bear on the questions raised by AI.
Emotion concepts and their function in a large language model
All modern language models sometimes act like they have emotions. What’s behind these behaviors? Our interpretability team investigates.
An update on our model deprecation commitments for Claude Opus 3
We are keeping Claude Opus 3 available post-retirement on claude.ai to all paid users, and making it available by request on the API. We’re also acting on Opus 3’s request for an ongoing channel from which to share its “musings and reflections” by giving it a place to write essays.
The persona selection model
Why would AI assistants behave like they’re human? We articulate a theory—drawing on ideas discussed by many others—that might help explain why modern AI training tends to create human-like AIs.
Claude is a space to think
No ads. No sponsored content. Just genuinely helpful conversations.
Claude's new constitution
A new approach to a foundational document that expresses and shapes who Claude is
Claude's Constitution
A detailed description of our vision for Claude’s values and behavior.
The assistant axis: situating and stabilizing the character of large language models
In a new paper, we look at several open-weights language models, map out how their neural activity defines a “persona space,” and situate the “Assistant” persona within that space.
Measuring political bias in Claude
We introduce and open-source an automated evaluation for political even-handedness, testing six models across 1,350 prompt pairs.
Commitments on model deprecation and preservation
We are committing to preserving the weights of all publicly released models, and all models that are deployed for significant internal use.
Claude Opus 4 and 4.1 can now end a rare subset of conversations
Claude Opus 4 and 4.1 can now end a rare subset of conversations. An update on our exploratory research on model welfare.
Persona vectors: Monitoring and controlling character traits in language models
In a new paper, we identify patterns of activity within an AI model’s neural network that control its character traits, which we call persona vectors.
How people use Claude for support, advice, and companionship
Only 2.9% of Claude conversations involve emotional support, advice, or companionship. We share research on affective use and how we're building safeguards.
Exploring model welfare
Announcing a new research program at Anthropic on model welfare
Values in the wild: Discovering and analyzing values in real-world language model interactions
We describe a practical method we’ve developed to observe Claude’s value, and provide the first large-scale results on how Claude expresses those values during real-world conversations.
How character training cultivates traits like curiosity, open-mindedness, and thoughtfulness in Claude using a variant of Constitutional AI.
Claude’s constitution
A detailed description of our vision for Claude’s values and behavior.
Anthropic is a Public Benefit Corporation. Our mission is the responsible development and maintenance of advanced AI for the long-term benefit of humanity.