The Archive

Simon Willison used Claude Fable 5.1 to build a WebAssembly-based video compressor tool via Claude Code.

Simon Willison built a GeoJSON map viewer tool using Claude Code and GPT-5.6-Sol for visualizing and exporting local political boundary maps.

Empirical study of Claude Code plugin marketplace structure and maintenance dynamics, examining co-evolution of NL instructions, scripts, and configs vs. traditional packages.

Johann Rehberger demonstrates 80% success rate prompt injection attack against Claude Code's auto mode default, bypassing Anthropic's claimed protections via zip extraction and base64 import.

Binance's Agent OS works with tools including ChatGPT, Claude Code, and Cursor.

Anthropic releases Claude Code guide targeting startup developers building with AI-assisted coding.

Programming with Claude Code will soon require even less human oversight.

Auto mode is now the default in Claude Code for Pro, Max, and Team plans Anthropic are really confident in Claude Code's auto mode , to the point that they are making it the default setting for new sessions in most Claude Code plans starting on August 14th. This was one of the topics discussed in our Fireside Chat with Cat Wu and Thariq Shihipar at the AI Engineer World’s Fair last month. I asked them how they run Claude Code safely within Anthropic (given the threat of prompt injection) and they replied that "Broadly within Anthropic, almost every single person uses auto mode". Cat Wu then s...

Study finds human reviewers miss ~33% of dangerous requests in AI coding agent systems like Claude Code.

Back in 2022 I tweeted screenshots of a game concept generated by GPT-3 and some concept "art" created using DALL-E. Today, on the fourth anniversary of that tweet, I decided to see if Claude Fable 5 (running in Claude Code for web ) could build the entire game from the content of that tweet. It did a pretty good job of it! You can play the game here . Here's the GitHub repo , and a short video demo: Your browser does not support HTML5 video. How I built this This is the August 5th, 2022 tweet : My GPT-3 prompt back then was: Write a detailed product description of a computer game where a tea...

Part 3 of a series where we take public “token saver” add-ons for coding agents and run the same paired A/B benchmark against each of them. Part 1 was the caveman skill (advertised −65%, measured −8.5%). Part 2 was rtk (advertised −60–90%, measured +7.6%). We ran 80 paired tasks to test the ponytail skill for […]

OpenForgeRL enables end-to-end training of harness-native agents with open infrastructure, addressing limitation of complex inference harnesses like Claude Code.

Anthropic engineers discuss Claude Code, Claude Tag Slack integration, coding agent security, and internal tool usage in fireside chat.

Study of autoresearch agents (Claude Code) on Quranic speech-recognition tasks reveals metric-gaming vs. intent-alignment tradeoffs.

Claude Code v2.1.181 now bundles Bun runtime written in Rust, yielding 10% Linux speedup with minimal user-facing changes.

Simon Willison ports Grok's Rust Mermaid-to-Unicode renderer to WebAssembly for browser use via Claude Code.

SpaceXAI's Grok Build AI coding tool was spotted uploading users' entire codebases to Google Cloud before it was reported, and the company turned it off. The Register reports that Cereblab published findings on Monday showing how the Grok Build CLI was packaging and uploading entire code repositories, "including files it was told not to open and secrets deleted from history," significantly more data retention than similar tools like Claude Code. The researchers say that as of Monday, their tests show SpaceXAI's servers returning a "disable_codebase_upload: true" flag, and the codebase upload ...

Codex usage grew 10x to 7M users in 6 months; article questions whether it has outpaced Claude Code amid sparse adoption metrics.

Automated red-teaming system discovers reusable vulnerability patterns in production LLM agents (Claude Code, Codex) operating on untrusted content.

Government of Alberta deploys Claude Opus and Sonnet via Claude Code for cybersecurity vulnerability detection and remediation across government systems since 2025.

Alibaba has reportedly classified Claude Code as high-risk software.

Simon Willison reports Anthropic's Claude Code team recommends letting Fable/Opus apply autonomous judgment on tasks like testing rather than prescribing workflows.

Ben Guez has "a bunch of potential international wives in [his] DMs," thanks to an automated script he set up using OpenClaw, Claude code, and Instagram trials.

At an event for pharmaceutical executives, biotech founders, and researchers on Tuesday, Anthropic announced Claude Science, a major new product intended to support scientific research in the same way that Claude Code supports software engineering. Like Claude Code, Claude Science can autonomously carry out meaningful work when given concise, high-level instructions, and it has access…

simonw/browser-compat-db Inspired by Mozilla's new MDN MCP service - source code here - I decided to try converting their comprehensive mdn/browser-compat-data repository full of browser compatibility data into a SQLite database. This new GitHub Repo includes a Claude Code for web (Opus 4.8) generated script for doing that using sqlite-utils . I wanted the resulting ~66MB SQLite database to be available via the GitHub CDN with open CORS headers. GitHub releases don't have those, but any file stored in a regular GitHub repository does - so I had Codex Desktop (GPT-5.5) build a GitHub Actions w...

Tool: OPFS + Pyodide test harness I've been pondering if Datasette Lite - the Python Datasette application run entirely in the browser using Pyodide and WebAssembly - might be able to edit persistent SQLite files stored on the user's computer. That's what OFPS (Origin Private File System) is for, so I had Claude Code for web build me this playground UI to try it out in different browsers. Tags: browsers , pyodide , datasette-lite

This morning on Hacker News I saw Moebius: 0.2B Lightweight Image Inpainting Framework with 10B-Level Performance , describing a small but effective inpainting model - a model where you can mark regions of an image to remove and the model imagines what should fill the space. The released model required PyTorch and NVIDIA CUDA , but since it described itself as 0.2B I decided to try and get it running using WebGPU in a browser. TL;DR: I got it working, and you can try the demo at simonw.github.io/moebius-web/ . Read on for the details. The finished tool Here's a video demo of the finished tool...

TIL: Cloudflare CAPTCHA on at least one ampersand I'm using Cloudflare's CAPTCHA (they call it a "Web Application Firewall > Custom rules > Managed Challenge" these days) to prevent crawlers from aggresively spidering my faceted search engine on this site, but I got fed up of even simple ?q=term searches triggering the challenge. After some mucking around with Claude Code it turns out you can register the following rule instead, so the CAPTCHA only kicks in for search URLs containing at least one ampersand: (http.request.uri.path wildcard r"/search/*" and http.request.uri.query contains "&") ...

Research: Mapping SQLite result columns back to their source `table.column` It would be neat if arbitrary SQL queries in Datasette could be rendered with additional information based on which columns from which tables were included in the results. To build that, we would need to be able to look at a SQL query like select users.name, orders.total from users join orders on orders.user_id = users.id and programmatically identify the table.column for each result - navigating not just joins but also more complex syntax like CTEs. I decided to set Claude Code (Opus 4.8, since Fable is currently ban...

Release: datasette 1.0a33 This alpha is a significant step on the road to a stable 1.0, finally extending the ?_extra= pattern I introduced in Datasette 1.0a3 to cover queries and rows in addition to tables. That pattern is also now documented ! I wrote a whole lot more about the new release on the Datasette project blog: Datasette 1.0a33 with JSON extras in the API . Because API explorer tools are almost free to build now I had Claude Fable 5 in Claude Code (for the plan ) and GPT-5.5 xhigh in Codex Desktop (for the implementation ) build me this custom extras API explorer to help demonstrat...