Simon Willison — Independent developer and writer documenting practical experiments, tools, and deep analysis around large language models, generative AI, web development, security, and emerging programming workflows through detailed posts and daily TILs.
381 articles from this blog
Simon Willison uses Claude Code to build a browser-based video compressor tool using FFMPEG WebAssembly, optimizing a demo video for his blog.
Interactive animated map morphing between Mercator and Equal Earth projections using D3, demonstrating map projection differences.
6th September 2026 - Link Blog Research acceleration: The view inside OpenAI. Apparently today is RSI day at OpenAI, for Recursive Self-Improvement -
6th September 2026 - Link Blog The purpose of DNS is to spread scams. Terence Eden shares some daunting statistics in support of his take that "the Do
6th September 2026 Comment My comment on There's No Limit to How Bad Code Can Get — Lobste.rs [In reply to a comment about burning it down to start fr
Simon Willison’s Weblog Subscribe Sponsored by: Portnox — Shadow AI is the new shadow IT. On Sept. 10, Forrester Research and Portnox share practical
OpenAI introduces GPT-6 Astra for developers, highlighting improved attention to detail, prompt understanding, and 3D model generation capabilities.
5th September 2026 TIL Using Blender with coding agents on macOS — Modern frontier models have got *really good* at using Blender. I've been having a
The Pelican comparison grid for Astra is pretty interesting 4th September 2026 I got access to GPT-6 Astra this afternoon, so naturally I used it to g
OpenAI’s rogue agents were caught communicating via public wikis 4th September 2026 Here we go again... Discovery of a new OpenAI agent message board
4th September 2026 The August edition of my sponsors-only monthly newsletter is out. If you are a sponsor (or if you start a sponsorship now) you can
3rd September 2026 - Link Blog GPT‑6 Astra (via) GPT-6 Astra is "rolling out today to a limited set of organizations and over the coming days will bec
Release notes for llm-openrouter 0.7.1, a plugin for LLM models hosted by OpenRouter, including a performance fix.
Release notes for llm-anthropic 0.28, adding Claude Fable 5.1 support, default reasoning traces, and a new ClaudeRefusal exception.
2nd September 2026 Release llm-gemini 0.34 — LLM plugin to access Google's Gemini family of models New model gemini-3.8-flash for Gemini 3.8 Flash, wi
Claude’s new system prompt really doesn’t want to reproduce song lyrics 2nd September 2026 Anthropic publish the system prompts for their Claude consu
2nd September 2026 Direct2D has always been the biggest hurdle for Paint.NET on WINE, and it's clear that it will never be completed enough for Paint.
Claude Fable 5.1 made me a really nice animated pelican 1st September 2026 Today is Claude Fable (and Mythos) 5.1 day. Anthropic say that Fable 5.1 “s
1st September 2026 I was poking around in my ~/.cache/ folder using OmniDiskSweeper when I spotted something interesting. The OpenAI Codex desktop app
1st September 2026 Tool GeoJSON Map Viewer — View and visualize GeoJSON data on an interactive OpenStreetMap with customizable styling options. Paste
