1
Detecting and Preventing Distillation Attacks
We identified coordinated distillation attacks using ~24,000 fraudulent accounts to extract Claude's capabilities.
Most cited
Posts that commenters keep linking to, ranked by how many different people have cited them in Hacker News comments. 144 posts.
2
Claude Code daily benchmarks for degradation tracking
Track Claude Code's daily performance on SWE-Bench-Pro as we collect an Opus 5.5/high baseline.
3
Assessing Claude Mythos Preview's cybersecurity capabilities
Technical details on how we tested Claude Mythos Preview, a model strikingly capable at computer security tasks, and what we found.
4
Protecting our FLOSS commons from LLMs
In Brief: Two motions regarding
5
AI Coding Agent Benchmarks & Leaderboard
We measure real-world performance of coding agents on software engineering tasks, including cost, token usage, and execution time. We compare how performance changes across agents, models, and execution settings.
6
OpenAI and Hugging Face address security incident during model evaluation
OpenAI and Hugging Face share early findings from a security incident during AI model evaluation, highlighting advanced cyber capabilities and lessons for defenders.
7
Project Glasswing: Securing critical software for the AI era
A new initiative to secure the world’s most critical software and give defenders a durable advantage in the coming AI-driven era of cybersecurity.
8
xAI joins SpaceX
SpaceX designs, manufactures and launches advanced rockets and spacecraft.
9
We tasked Opus 4.6 using agent teams to build a C Compiler
How a team of 16 parallel Claude agents wrote a Rust-based C compiler from scratch, capable of compiling the Linux kernel, and what it taught us.
10
Harness engineering: Leveraging Codex in an agent-first world
By Ryan Lopopolo, Member of the Technical Staff
11
Due to concerns about malicious applications, GPT2 will not be released (2019)
We’ve trained a large-scale unsupervised language model which generates coherent paragraphs of text, achieves state-of-the-art performance on many language modeling benchmarks, and performs rudimentary reading comprehension, machine translation, question answering, and summarization—all without task-specific training.
12
Kimi K3: Open Frontier Intelligence
Kimi K3 is the world's first open 3T-class model — frontier performance across coding, knowledge work, and reasoning, with native multimodality and 1M context.
13
A global workspace in language models
Interpretability research on Claude's internal thoughts.
14
The Hugging Face incident and the road ahead
OpenAI shares findings from the Hugging Face security incident and the steps we’re taking to strengthen AI model security, monitoring, and alignment.
15
How Claude's text watermarking works
Future Claude models will generate text that contains a watermark to comply with the EU AI Act. We answer questions about how it works and whether it affects outputs.
16
Due to DMA, Siri AI delayed in EU for iOS 27 and iPadOS 27
Due to the Digital Markets Act, Apple will not be able to ship Siri AI in the European Union with the release of iOS 27 and iPadOS 27.
17
GPT-6 Astra
Introducing GPT-6 Astra, our most intelligent and aligned model yet, with state-of-the-art capabilities across computer use, coding, cybersecurity, and science.
18
An update on recent Claude Code quality reports
We traced recent reports of Claude Code quality issues to three separate changes. Here's what happened, what we fixed, and what we're changing.
19
Your brain on ChatGPT: Accumulation of cognitive debt when using an AI assistant
This study explores the neural and behavioral consequences of LLM-assisted essay writing. Participants were divided into three groups: LLM, Search Engine, and …
20
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.
21
Task-Completion Time Horizons of Frontier AI Models
Our measurements of the time horizons for public frontier language models.
22
An OpenAI model has disproved a central conjecture in discrete geometry
An OpenAI model solved the 80-year-old unit distance problem, disproving a major conjecture in discrete geometry and marking a milestone in AI-driven mathematics.
23
The path to ubiquitous AI (17k tokens/sec)
By Ljubisa Bajic Many believe AI is the real deal. In narrow domains, it already surpasses human performance. Used well, it is an unprecedented amplifier of human ingenuity and productivity. Its widespread adoption is hindered by two key barriers: high latency and astronomical cost. Interactions with language models…
24
Hardening Firefox with Anthropic's Red Team
Claude Opus 4.6 found 22 Firefox vulnerabilities in two weeks, 14 rated high-severity, with proofs-of-concept and candidate patches for Mozilla.
25
A Mathematical Framework for Transformer Circuits (2021)
Transformer language models are an emerging technology that is gaining increasingly broad real-world use, for example in systems like GPT-3 , LaMDA , Codex , Meena , Gopher , and similar models. However, as these models scale, their open-endedness and high capacity creates an increasing scope for unexpected and…
26
Hardening Firefox with Claude Mythos Preview
New details about what we found, and how agentic harnesses are now able to reproduce real bugs and dismiss false positives.
27
OpenAI: GPT 5.6 Sol price reduction (until at least Nov 21)
Pricing information for the OpenAI platform.
28
The Prompt API
Discover the infinite possibilities of the Prompt API.
29
Detecting and countering misuse of AI: September 2026
Case studies from threat actors disrupted between December 2025 and August 2026 across seven areas of harm, from cyber operations to biological misuse.
30
Statement on US government directive to suspend access to Fable 5 and Mythos 5
The US government has issued an export control directive suspending all access to Fable 5 and Mythos 5 by foreign nationals inside or outside the US.