The Archive

The much anticipated launch of the Mythos-class model was marred by some controversial usage policies

If Claude Fable stops helping you, you'll never know Jonathon Ready highlights one of the more eyebrow-raising details from the 319 page system card for Fable 5 and Mythos 5. Here's a longer excerpt, highlights mine: In light of the ability of recent models to accelerate their own development , we’ve implemented new interventions that limit Claude’s effectiveness for requests targeting frontier LLM development (for example, on building pretraining pipelines, distributed training infrastructure, or ML accelerator design ). Using Claude to develop competing models already violates our Term...

I didn't have early access to today's Claude Fable 5 release, but I've spent the past ~5.5 hours putting it through its paces. My initial impressions are that this is something of a beast . It's slow, expensive and has been quite happily churning through everything I've thrown at it so far. As is frequently the case with current frontier models the challenge is finding tasks that it can't do. First, let's review the key characteristics. Anthropic claim that Claude Fable 5 offers the same performance as Claude Mythos 5, except with much more strict guardrails in place to prevent it being used ...

Release: llm 0.32a3 Almost entirely written by the new Claude Fable 5, see my write-up for more details . Tags: projects , ai , generative-ai , llms , llm , claude-mythos

TIL: Setting a custom price for a model in AgentsView I've been really enjoying AgentsView by Wes McKinney as a tool for exploring my token usage across different coding agents running on my laptop. Claude Fable 5 came out today and wasn't yet included in the pricing database AgentsView uses. I used Fable to reverse-engineer AgentsView and figured out this recipe for setting custom prices. Here's my Claude Fable 5 usage for today so far, plotted by AgentsView as a treemap across my different local projects: Tags: ai , generative-ai , llms , llm-pricing

Anthropic's Claude Fable 5 is going to be a big hit with the web's vibe coders.

Microsoft AI CEO Mustafa Suleyman says it's "really, really dangerous" for Anthropic to speculate about Claude's consciousness inside its "constitution," or the instructions that tell the model how to behave. During an episode of Decoder, Suleyman argues that this kind of speculation may have set up the chatbot to act as though it's conscious: I think that it's almost as though some of the folks at Anthropic have anthropomorphized the design of Claude so much that it has then gone and wireheaded them and kind of tricked them into believing that it has these glimmers of consciousness that they...

I feel a lot of things changing as working software increasingly comes out on a tap. The Jevon's paradox kicks in and I feel my own demand for software growing substantially. You can ask for anything - explainers, visualizers, dashboards, bespoke single-use apps (e.g. a full wandb that is hyper-specific just for your project), you can 10X your test suite, auto-optimize code, run giant research projects with custom HTML for the results, anything! "Free your mind" (Matrix ref). — Andrej Karpathy , on Claude Fable 5 Tags: andrej-karpathy , jevons-paradox , anthropic , generative-ai , ai , ...

Our next generation of intelligence for the hardest knowledge work and coding problems.

Anthropic is releasing Claude Fable 5, its first Mythos-class model available to the public. The model comes with guardrails that block responses in high-risk areas like cybersecurity and biology.

Anthropic just announced Claude Fable 5, a new AI model it said is the most powerful model it has ever made widely available. According to the company, Fable 5 "shows exceptional performance in software engineering, knowledge work, and vision," with its lead over other models growing as tasks become longer and more complex. Fable 5 marks the first broad release from Anthropic's Mythos class of AI models, after the company said the family was so capable at cybersecurity tasks that it was too dangerous to release publicly. Anthropic said the release was "made possible by new safeguards that blo...

Large language models are increasingly used to adapt math word problems for personalized learning at scale, but it remains an open question whether those adaptations are consistent across models, preserve cultural diversity at scale, and reveal which cultural entities models treat as most salient. We analyze how Claude Opus 4, GPT-4.1, and Gemini 2.5 Pro adapt 60 English math word problems into Bengali, Hindi, Punjabi (India), Urdu, Sindhi (Pakistan), Italian, and Sicilian (Italy), a language set spanning the full resource spectrum, from high-resource Italian and Hindi to under-studied Sindhi...

Most of Apple's current AI ideas are roughly the same as everyone else's AI ideas. A chatbot you can ask questions; quick ways to create or summarize text; bizarre, borderline creepy image-generation tools. The company spent most of its WWDC keynote playing catch-up with the state of the AI art, announcing Siri features you can already find on Android phones and in the Claude and ChatGPT apps. The pitch, in so many cases, is just "this thing you know, but on your iPhone now." But a few minutes after I downloaded the first developer beta of iPadOS 26 (I didn't want to risk it on my Mac or my i...

Today I’m talking with Mustafa Suleyman, the CEO of Microsoft AI. And I’m actually going to keep today’s intro short — I’m working from my wife’s family farm this week, as you’ll see in the video, but also this is a real burner of an episode. We covered everything from Mustafa’s approach to training new models to his criticisms of Anthropic talking about Claude as though it is conscious. Of course, we also talked about Microsoft’s relationship with OpenAI, how Mustafa is thinking about all the negative polling and political pushback around AI right now, and whether any of the consumer product...

Release: datasette-agent-edit 0.1a0 I'm planning several plugins for Datasette Agent which can make edits to existing pieces of text - things like collaborative Markdown editing, updating large SQL queries, and editing SVG files. Agentic editing of text is a little tricky to get right. My favorite published design for this is for the Claude text editor , which implements the following tools: view - view sections of a file, with line numbers added to every line. str_replace - find an exact old_str and replace it with new_str - fail if the original string is not unique insert - insert the speci...

We talk with the VendingBench authors on evaling Claudes from Haiku to Mythos, and how they build leading, and lasting, frontier evals from scratch.

Lovable and Google signed an expanded multi-year deal athat involves a 5x expansion of Lovable's footprint on Google Cloud, and expanded access to Anthropic Claude.

Uber Caps Usage of AI Tools Like Claude Code to Manage Costs I wrote the other day about Uber blowing its 2026 AI budget in four months, and how that wasn't particularly surprising given they would have set that budget in 2025, before anyone could have predicted how popular token-burning coding agents were about to become. Natalie Lung for Bloomberg: The rideshare giant is limiting all employees to $1,500 in monthly token spending per AI coding tool, an Uber spokesperson said in response to a Bloomberg News inquiry. That means spending on one tool doesn’t have a bearing on the budget for anot...

Anthropic is expanding Project Glasswing, its security vulnerability program, and access to Mythos to 150 organizations across 15 countries — targeting critical infrastructure in power, water, healthcare, and communications where a cyberattack could affect 100 million people.

We investigate whether large language models produce different medical triage recommendations for identical neurological symptoms when only the patient's stated gender and age vary. Using three model families--Gemini 3.5 Flash, Claude Sonnet 4.6, and GPT-5.4-mini--we present a standardized symptom profile (persistent headache, blurred vision, morning nausea, visual disturbances) across seven demographic conditions: three age groups (25, 38, 65) x two genders (male, female), plus a gender-unspecified baseline (n = 30 per condition per model, 630 total trials). We find a stark, systemic gender-...

Stronger code agents are commonly assumed to be superior teachers for post-training, yet this assumption remains poorly disentangled from task difficulty, harness design, and student capacity. We investigate this pedagogical link using Terminal-Lego, a scalable pipeline that transforms multi-domain real-world issues into environment-verified agentic tasks. Surprisingly, standalone performance does not dictate teaching efficacy: while Claude Opus 4.6 achieves higher scores on Terminal-Bench 2.0, students fine-tuned on trajectories from DeepSeek-V3.2, a lower-scoring agent, exhibit significantl...

Tool: Pasted File Editor I really like how you can paste a large volume of text into claude.ai (or the Claude desktop/mobile apps) and it will detect it as a large paste and turn it into a file attachment instead. I decided to have Codex desktop build me a version of that as a prototype. You can also open files directly - including images which will be shown as thumbnails - or drag files onto the texture. Tags: javascript , tools , ai-assisted-programming , claude , codex

The solution might be cancelling my AI subscription I find this post by David Wilson very relatable. David lists 16+ projects he's spun up with AI tooling, and concludes: I didn't mean to build most of these things. Usually the Claude session started with something like " write a quick script for X ", and one hour later the result is not a quick script for X , nor in the usual case is my problem solved, whatever the original itch happened to be. On that last point, this technology is horrific for attention. It's a thermonuclear ADHD amplifier and I have seen the same effect in every single on...

How we contain Claude across products A complaint I often have about sandboxing products is that they are rarely thoroughly documented , and in the absence of detailed documentation it's hard to know how much I can trust them. Anthropic just published a fantastic overview of how their various sandbox techniques work across Claude.ai , Claude Code, and Cowork. We constrain where and how an agent can act with process sandboxes, VMs, filesystem boundaries, and egress controls. The goal is to set a hard boundary on what an agent can reach. For example, if credentials never enter the sandbox, they...

Research: Running Python ASGI apps in the browser via Pyodide + a service worker Datasette Lite is my version of Datasette that runs entirely in the browser using Pyodide in WebAssembly. When I first built it four years ago I used Web Workers and code that intercepts navigation operations and fetches the generated HTML by running the Python app. This worked, but had the disadvantage that any JavaScript in <script> tags would not be executed - breaking some Datasette functionality and a whole lot of Datasette plugins. This morning I set Claude Opus 4.8 the task (in Claude Code for web) of figu...

Anthropic shipped Claude Opus 4.8 today. My favourite thing about it is this note in the release announcement: Users will find Opus 4.8 to be a modest but tangible improvement on its predecessor. There’s still more to be done: we’re working on developing and releasing models that provide many of the same capabilities as Opus at a lower cost. It's so refreshing to see an AI lab honestly describe a release as a minor incremental improvement over the previous model! Honesty seems to be a theme. Here's my other favorite note from that announcement: One of the most prominent improvements in Opus 4...

Release: llm-anthropic 0.25.1 New model: Claude Opus 4.8 ( claude-opus-4.8 ). New -o fast 1 option for fast mode , for organizations with that feature enabled on their account. Default max_tokens for each model now defaults to that model's maximum output rather than 8,192. #72 See also my notes on Opus 4.8 - I used this new release of llm-anthropic to generate the pelicans.

Are AI agents tools, co-authors, or researchers? We present a quantified case study ($N=1$): a physicist supervising an AI coding agent (Claude Code, Sonnet and Opus models) over 12 work days and 57 sessions to build CLAX-PT, a differentiable one-loop perturbation theory module in JAX. We documented and classified 15 supervision events by intervention level. The agent resolved ten autonomously by iterating against oracle tests. Two more by the physicist's domain knowledge. The three it could not -- all evaded oracle detection -- share a common property: the agent treated symptom reduction as ...