Simon Willison's Weblog: Entries

Claude Opus 4.8: "a modest but tangible improvement"

May 28, 2026, 11:59 PM Simon Willison's Weblog: Entries

I think Anthropic and OpenAI have found product-market fit

May 27, 2026, 4:38 PM Simon Willison's Weblog: Entries

Notes on Pope Leo XIV's encyclical on AI

May 25, 2026, 11:58 PM Simon Willison's Weblog: Entries

Datasette Agent

May 21, 2026, 7:52 PM Simon Willison's Weblog: Entries

Gemini 3.5 Flash: more expensive, but Google plan to use it for everything

May 19, 2026, 10:40 PM Simon Willison's Weblog: Entries

The last six months in LLMs in five minutes

May 19, 2026, 1:09 AM Simon Willison's Weblog: Entries

Notes on the xAI/Anthropic data center deal

May 7, 2026, 5:09 PM Simon Willison's Weblog: Entries

Live blog: Code w/ Claude 2026

May 6, 2026, 3:58 PM Simon Willison's Weblog: Entries

Vibe coding and agentic engineering are getting closer than I'd like

May 6, 2026, 2:24 PM Simon Willison's Weblog: Entries

LLM 0.32a0 is a major backwards-compatible refactor

Apr 29, 2026, 7:01 PM Simon Willison's Weblog: Entries

Tracking the history of the now-deceased OpenAI Microsoft AGI clause

Apr 27, 2026, 6:38 PM Simon Willison's Weblog: Entries

DeepSeek V4 - almost on the frontier, a fraction of the price

Apr 24, 2026, 6:01 AM Simon Willison's Weblog: Entries

Extract PDF text in your browser with LiteParse for the web

Apr 23, 2026, 9:54 PM Simon Willison's Weblog: Entries

A pelican for GPT-5.5 via the semi-official Codex backdoor API

Apr 23, 2026, 7:59 PM Simon Willison's Weblog: Entries

Is Claude Code going to cost $100/month? Probably not - it's all very confusing

Apr 22, 2026, 2:07 AM Simon Willison's Weblog: Entries

Where's the raccoon with the ham radio? (ChatGPT Images 2.0)

Apr 21, 2026, 8:32 PM Simon Willison's Weblog: Entries

Changes in the system prompt between Claude Opus 4.6 and 4.7

Apr 18, 2026, 11:59 PM Simon Willison's Weblog: Entries

Join us at PyCon US 2026 in Long Beach - we have new AI and security tracks this year

Apr 17, 2026, 11:59 PM Simon Willison's Weblog: Entries

Qwen3.6-35B-A3B on my laptop drew me a better pelican than Claude Opus 4.7

Apr 16, 2026, 5:16 PM Simon Willison's Weblog: Entries

Meta's new model is Muse Spark, and meta.ai chat has some interesting tools

Apr 8, 2026, 11:07 PM Simon Willison's Weblog: Entries

Anthropic's Project Glasswing - restricting Claude Mythos to security researchers - sounds necessary to me

Apr 7, 2026, 8:52 PM Simon Willison's Weblog: Entries

The Axios supply chain attack used individually targeted social engineering

Apr 3, 2026, 1:54 PM Simon Willison's Weblog: Entries

Highlights from my conversation about agentic engineering on Lenny's Podcast

Apr 2, 2026, 8:40 PM Simon Willison's Weblog: Entries

Mr. Chatterbox is a (weak) Victorian-era ethically trained model you can run on your own computer

Mar 30, 2026, 2:28 PM Simon Willison's Weblog: Entries

Vibe coding SwiftUI apps is a lot of fun

Mar 27, 2026, 8:59 PM Simon Willison's Weblog: Entries

Experimenting with Starlette 1.0 with Claude skills

Mar 22, 2026, 11:57 PM Simon Willison's Weblog: Entries

Profiling Hacker News users based on their comments

Mar 21, 2026, 11:59 PM Simon Willison's Weblog: Entries

Thoughts on OpenAI acquiring Astral and uv/ruff/ty

Mar 19, 2026, 4:45 PM Simon Willison's Weblog: Entries

GPT-5.4 mini and GPT-5.4 nano, which can describe 76,000 photos for $52

Mar 17, 2026, 7:39 PM Simon Willison's Weblog: Entries

My fireside chat about agentic engineering at the Pragmatic Summit

Mar 14, 2026, 6:19 PM Simon Willison's Weblog: Entries

Perhaps not Boring Technology after all

Mar 9, 2026, 1:37 PM Simon Willison's Weblog: Entries

Can coding agents relicense open source through a “clean room” implementation of code?

Mar 5, 2026, 4:49 PM Simon Willison's Weblog: Entries

Something is afoot in the land of Qwen

Mar 4, 2026, 3:50 PM Simon Willison's Weblog: Entries

I vibe coded my dream macOS presentation app

Feb 25, 2026, 4:46 PM Simon Willison's Weblog: Entries

Writing about Agentic Engineering Patterns

Feb 23, 2026, 5:43 PM Simon Willison's Weblog: Entries

Adding TILs, releases, museums, tools and research to my blog

Feb 20, 2026, 11:47 PM Simon Willison's Weblog: Entries