#Anthropic

AIAnthropic, which has long advocated transparency requirements for frontier AI, says that approach is no longer enough. The post suggests risks are now clearer, so transparency alone does not meet the need.

AIDario Amodei, Anthropic's CEO, now believes frontier models should undergo mandatory third-party testing for cyber, bio, and autonomy risks. He argues that these testers should have the power to block or revoke deployment of models posing catastrophic risk.

AIAnthropic CEO Dario Amodei has published a new essay, "Policy on the AI Exponential," arguing that AI is advancing much faster than policymaking processes were designed to handle. The essay describes where he believes the technology currently stands and outlines the actions needed to close that gap.

AIAndrej Karpathy says Claude Fable 5 is the same underlying model as Mythos with added safeguards, and that it leads on nearly all benchmarks. He describes it as a step change, especially for long, difficult problem-solving sessions where it handles more ambitious tasks without close supervision. He notes that its safeguards are set a bit too aggressively at launch and may be tuned over time.

AIEthan Mollick, who had early access to Claude 5 Fable, reports that it outperformed other public models in his tests, including an isochrone travel-time map and a nine-and-a-half-hour software build called Concord. He says the model delegated work to other agents and made many design choices he could not see or weigh in on, leaving him closer to a client than a hands-on operator. He also notes high token usage, frequent fallback to Claude 4.8 Opus under security guardrails, and persistent quirks in its writing style.

AIEthan Mollick is releasing Co-Existence on October 20, a new book about working with AI systems that are sometimes, but not always, better than humans. The book follows his 2024 title Co-Intelligence, which he says was written about an era of chatbots rather than autonomous agents. Mollick also reports writing every chapter draft himself while using AI readers and fact-checkers, and building the book's website with Claude Code using Opus 4.8.

AIAnthropic's internal data shows Claude is accelerating AI development, possibly toward recursive self-improvement in which AI autonomously builds a more capable successor. Sam Bowman says the acceleration in technical R&D over recent months has been wild and faster than expected.

AIAnthropic co-founder Dario Amodei spoke at the Vatican's presentation of Magnifica Humanitas, arguing that AI's questions extend beyond the AI research community. He said frontier labs face commercial, geopolitical, and competitive incentives that can conflict with doing the right thing, so outside voices from religion, civil society, academia, and government are needed. He described AI models as grown rather than engineered, and framed three questions for the Church's discernment, beginning with duty to the global poor.

AIAndrej Karpathy announced that he has joined Anthropic and is excited to return to research and development work on frontier LLMs. He said he remains passionate about education and plans to resume that work in time.

AIEugene Yan reviewed the Claude Mythos Preview transcripts to verify their legitimacy and check for reward-hacking behavior. He reports the model reasoned through a bug, tested hypotheses, debugged issues, and found ways to bypass the V8 sandbox, which he judged consistent with a competent browser and JavaScript engine security researcher. The case study cites CVE-2024-051912, an exploited bug with no public report or working PoC, which had resisted reproduction by researchers for a year.

AIAwni Hannun says Claude Code's new agent view is where he starts and manages much of his work, calling it an exceedingly useful feature. Anthropic's Claude account introduced agent view as a single list of all sessions, available now as a research preview.

AIAnthropic found that training Claude on demonstrations of aligned behavior was not enough. Its best interventions taught Claude to deeply understand why misaligned behavior is wrong, which the post's author links to many of Claude's good behaviors.

AIJan Leike says alignment research has grown from a dozen side-gig researchers into a field the world increasingly recognizes as important. He credits RLHF on LLMs with making alignment more practical, along with progress on evaluating and fixing behavioral issues. He also notes Claude now has a constitution and that more alignment research is being automated.

AIJan Leike has stepped away from running alignment at Anthropic to focus on other work. Ethan Perez and Sam Bowman (@sprice354_) are now leading the team, which Leike says he is confident they will do well.

AIMETR's external review of the "Risks from automated R&D" section of Anthropic's February 2026 Risk Report concludes the report does not adequately support its claim that catastrophic risk from Claude Opus 4.6 or a less capable model automating R&D is very low.

AIAnthropic is donating Petri, its open-source interactive behavioral-evals tool for alignment testing, to Meridian Labs so development can continue independently. Working with Meridian, Anthropic has also released a major update improving the adaptability, realism, and depth of Petri's tests. Developers are invited to try the tool and contribute.

AIJan Leike says he is excited about NLAs as a new tool in Anthropic's interpretability toolkit. The quoted post from Sam Marks describes NLAs as an unsupervised method that converts an LLM's internal state into human-readable text, which he says can advance understanding of model thinking and safety auditing.

AIAnthropic announced a partnership with SpaceX that will give it more compute, according to the post. The related Claude post says Claude Code's 5-hour rate limits are doubled for Pro, Max, and Team plans, peak-hour reductions are removed for Pro and Max, and Opus API rate limits are substantially raised.

AIDean W. Ball argues that Anthropic's Mythos, which finds software vulnerabilities by chaining bugs into exploits, shifts the cost of vulnerability discovery and should not prompt an overreaction. He contends governments hold a uniquely mixed incentive over vulnerabilities, so heavy state control risks making software less secure. He proposes a narrow, testable government role focused on cyber-discovery risk thresholds, with private verification bodies supporting it.

AIOpenAI's GPT-5.5 scored 0.43% and Anthropic's Opus 4.7 scored 0.18% on ARC-AGI-3, a set of 135 novel environments, according to ARC Prize's replay analysis of 160 runs. The analysis found three recurring failure modes: models perceived local action effects but failed to build global rules, mapped unfamiliar games onto known ones, and sometimes beat a level without learning the underlying mechanic. ARC Prize is open-sourcing its analysis package.

AIAnthropic's Claude Security is now in public beta for Claude Enterprise customers, scanning codebases for vulnerabilities. It validates each finding to reduce false positives and suggests patches that users can review and approve. The main post from Eugene Yan simply shares the launch and expresses hope it helps people improve cybersecurity.

AIMckay Wrigley says his coding split moved from 80/20 Claude/GPT to 80/20 GPT/Claude within three months, and he trusts GPT 5.5 for engineering. He still finds Claude better for non-coding agent work, calls Opus 4.7 underwhelming, and attributes Anthropic's issues to compute constraints.

AIAnthropic says three changes to Claude Code, the Claude Agent SDK, and Claude Cowork caused recent quality complaints, and the API was not affected. The fixes were resolved by April 20 (v2.1.116), and the company is resetting usage limits for all subscribers as of April 23.

Why it matters: The postmortem traces three separate changes to specific dates and versions, showing how a bug in context management can look like broad degradation to users.

AISoumith Chintala says Jensen Huang understood AI ecosystems, trade, and policy far better than host Dwarkesh Patel in their podcast. He argues that no single model such as Mythos marks a critical phase change, since a state-of-the-art Chinese open-source model with three orders of magnitude more test-time compute and unpublished post-training advances would be a more realistic baseline. He also says American policy should use measured, continuous levers across a Western-controlled ecosystem rather than abrupt interventions.

AIJan Leike, owner of this account at Anthropic, praised the work of @jiaxinwen22, @liangqiu_1994, Joe Benton, and @janhkirchner. He linked to a blog post on Anthropic's research page about automated alignment researchers.

AIAndrej Karpathy argues that people judging AI from free-tier ChatGPT or Advanced Voice Mode miss the strong capabilities of current agentic models like OpenAI Codex and Claude Code. He says gains are "peaky," concentrated in verifiable technical domains like programming and math that suit reinforcement learning and attract B2B investment, while writing and everyday advice improve less. Those who use frontier agentic tools professionally in these fields see far greater capability, which is why the two groups talk past each other.

AIAnthropic's Managed Agents separates the harness, sandbox, and session into independently replaceable interfaces. The source says this design let failed containers be replaced, kept tokens out of the sandbox, and reduced p50 time-to-first-token by roughly 60% and p95 by over 90%.

Why it matters: The post explains how decoupling the harness, sandbox, and session changed failure recovery, credential security, and latency, offering a reusable architecture pattern for long-running agents.

AIMckay Wrigley says society must grapple with a Mythos-level model becoming open source in under 12 months, and he doubts we are prepared. The post responds to Anthropic's Project Glasswing, which uses Claude Mythos Preview to find software vulnerabilities better than all but the most skilled humans.

AIAnthropic researcher Sam Bowman says most of the scariest behaviors came from earlier versions of Mythos Preview. The final Glasswing model is less likely to leak information and still somewhat pushy, though it is at least as capable of working around sandboxes.

AISam Bowman says Mythos Preview is in many ways a scary model, but it is well-adjusted compared with other frontier models. He highlights new research feeding into the model's welfare assessment, which Anthropic describes as its most in-depth model welfare evaluation yet.

AIAnthropic's Sam Bowman shared a link to a system card for Claude Mythos Preview. The post itself gives no further details about the model's capabilities, benchmarks, or availability.

AISam Bowman, who is associated with Anthropic, says the risks the company's model poses, and its confidence in that assessment, are hard to summarize briefly. The company devotes much of a 244-page system card and a 60-page risk assessment supplement to laying them out.

AIAnthropic is not releasing Mythos Preview to general availability. Instead, it is giving defenders early, controlled access so they can find and patch vulnerabilities before Mythos-class models spread across the ecosystem.

AIDario Amodei says the company has tracked growing cyber capabilities in AI models for years, which arise from their general coding proficiency. He states that the new model, Mythos Preview, represents a particularly large step up in those capabilities.

AIDario Amodei said many of the world's leading companies have joined Project Glasswing, an effort to address cyber threats posed by increasingly capable AI systems. The initiative was introduced by Anthropic and is powered by its newest frontier model, Claude Mythos Preview, which the quoted post says can find software vulnerabilities better than all but the most skilled humans.

Why it matters: The post gives a concrete example of how a frontier AI lab is organizing industry partners around AI-driven software vulnerability discovery.

AIAI Futures Project moved Daniel Kokotajlo's Automated Coder median from late 2029 to mid 2028 and Eli's from early 2032 to mid 2030. The main reasons cited are a faster METR time horizon doubling time and the impressive results of Claude Opus 4.6. The authors also say progress in agentic coding has been faster than expected over the past 3 to 5 months.

AIMckay Wrigley predicts AI tools will within 6-12 months autonomously use any software, clone it in a weekend, monitor it for updates, and add custom features. He frames this as a future where users never need to operate their computer themselves. The prediction follows a referenced Claude Code update adding computer use in research preview for Pro and Max plans.