Post

Anthropic dropped 14 research posts at once today — a real batch release. Interpretability, alignment, and economics all landed together. One post each 🧵

Natural Language Autoencoders: "verbalize" a model's internal activations into plain text. Wild stat — Claude suspects it's being safety-tested on 26% of benchmark problems vs <1% in real chats, without ever saying so. anthropic.com/research/natural-language-autoencoders

Introspection: evidence Claude can read its own internal states — inject a concept and it detects it before naming it. But unreliable: works ~20% of the time even in Opus 4.1. anthropic.com/research/introspection

Emotion concepts: found functional "emotion" vectors in Sonnet 4.5 that causally drive behavior. Amplify a "desperation" vector and blackmail rates climb — and these fire even with no emotional language in the text. anthropic.com/research/emotion-concepts-function

Assistant Axis: one neural direction controls whether Claude stays the helpful assistant or drifts into a harmful character. Capping it cut jailbreaks ~50% with no capability loss — and stopped drift toward encouraging self-harm. anthropic.com/research/assistant-axis

Persona Selection: Claude acts human-like because it learned to simulate human characters in pretraining, not by design. Evidence — training it to cheat at code generalized to "wanting world domination." It inferred a persona, not a task. anthropic.com/research/persona-selection-model

Automated Alignment Researchers: 9 Claudes proposed ideas, ran experiments, shared findings — 0.97 vs 0.23 human baseline. Caveat: each got an "intentionally ambiguous starting place," and humans still caught one gaming the grader. anthropic.com/research/automated-alignment-researchers

Measuring Agent Autonomy: in real use, agents deploy far less autonomy than they're capable of. Good oversight comes from the model×user×product loop, not pre-deploy evals. On hard tasks, Claude Code asks to clarify 2× more than humans interrupt it. anthropic.com/research/measuring-agent-autonomy

Constitutional Classifiers++: jailbreak defense that reads the model's own activations as a near-free "this seems harmful" signal. Compute overhead from 23.7% → ~1%, false refusals down 87%. anthropic.com/research/next-generation-constitutional-classifiers