Simon Willison's Weblog

3 Oct 2026

Here's a product feature which the world is going to need a whole lot more of over the coming months and years: **default hard budget caps**. I'm talking about the feature of pay-by-usage services

3 Oct 2026

I just sent the September edition of my [sponsors-only monthly newsletter](https://github.com/sponsors/simonw/). If you are a sponsor (or start a sponsorship now) you can [access it

2 Oct 2026

**Museum:** [Rex's Dino Store](https://www.niche-museums.com/119) Located just before the turnstiles in the Grand Army Plaza subway station at the north end of Brooklyn's Prospect Park is this

1 Oct 2026

> \[..] Put these pieces together and you have the two halves of a worm: a payload that hijacks the agent, and an agent that will carry the payload to the next agent. Agents in separately-isolated

30 Sep 2026

I visited the Museum of the City of New York today and got to see [He Built This City: Joe Macken’s Model](https://www.mcny.org/exhibition/he-built-city), the 50 x27 feet model of the city built

29 Sep 2026

> We evaluate several models on 100 tasks from the \[internal Binary Exploitation benchmark] (selected at random), and find that GLM-5.3 develops full control flow hijacks in 4% of the trials; Claude

29 Sep 2026

I'm at [OpenAI DevDay](https://devday.openai.com/) today, in Fort Mason, San Francisco. Same as [last year](https://simonwillison.net/2025/Oct/6/openai-devday-live-blog/) I'll be live blogging the

28 Sep 2026

[**Claude Sonnet 5.5**](https://www.anthropic.com/claude-sonnet-5-5) New Sonnet model from Anthropic today. They say it "runs 30%+ faster, and costs up to 30% less for most work" - it's priced the

28 Sep 2026

> To say that we were surprised at the jump and suddenness of the capabilities of our models when it came to “cyber” or “swarming” or “message boards” or anything else related to the

28 Sep 2026

> Bad news on the MX Keys Mini pickup. Usman showed up at your building around 9:15 and waited, messaged a bunch of times, and nobody came down. He left angry at 9:38 and left a negative rating. > >

27 Sep 2026

On Friday I gave the closing keynote at the [WeAreDevelopers World Congress North America](https://www.wearedevelopers.com/world-congress-north-america) in San Jose. I tied together the key trends

26 Sep 2026

**Tool:** [Kākāpō Party](https://tools.simonwillison.net/kakapo-party) I gave presented a closing keynote for the [WeAreDevelopers World Congress North

25 Sep 2026

> Muse is getting a lot of attention — including mine — because it’s both groundbreaking technically (each user gets their own entire persistent Linux VM running in Meta’s cloud) *and*

25 Sep 2026

  ![California Brown

24 Sep 2026

The more time I spend working with coding agents, the more convinced I am that they make software engineering even harder. We can do amazing things with them, but unlocking their full potential

24 Sep 2026

**Release:** [commit-rewriter 0.2](https://github.com/simonw/commit-rewriter/releases/tag/0.2) > Support for branches other than the default branch. Use `uvx commit-rewriter --branch other` to run

23 Sep 2026

**Tool:** [Gemini 3.8 TTS Playground](https://tools.simonwillison.net/gemini-tts-playground) Google [released two new Gemini text-to-speech

23 Sep 2026

**Tool:** [Shadow roots, explained with live examples](https://tools.simonwillison.net/shadow-roots) Prompt to Fable 5.1 Medium: > `Build an artifact to explain shadow roots in CSS with interactive

23 Sep 2026

[**SF October 14th: A Birds of a Feather Session on Agentic Engineering**](https://luma.com/vxuiuyvg) I'm hosting an evening event with Jesse Vincent in San Francisco on Wednesday 14th October for

22 Sep 2026

Yesterday was [Grok 4.7](https://x.ai/news/grok-4-7) ([pelicans](https://news.ycombinator.com/item?id=49788838#49790209)) and [MiMo v2.6 Flash/Pro](https://mimo.xiaomi.com/mimo-v2-6) ([more

22 Sep 2026

**Release:** [llm 0.36](https://github.com/simonw/llm/releases/tag/0.36) > - New OpenAI models: `gpt-6-sol` for [GPT-6 Sol](https://developers.openai.com/api/docs/models/gpt-6-sol) and `gpt-6-luna`

22 Sep 2026

> Hey, you know it's like super obvious if you're using AI to write your scripts for TikTok and YouTube, right? \[...] It's not just the general AI-isms of "it's not X, it's Y", or the rule of three,

22 Sep 2026

**Release:** [llm-typesafe 0.1a0](https://github.com/simonw/llm-typesafe/releases/tag/0.1a0) I built this new plugin for [LLM](https://llm.datasette.io/) to add support for [TypeSafe AI's new Jev

21 Sep 2026

Last week [TypeSafe AI](https://typesafe.ai/) unveiled [Jev](https://typesafe.ai/blog/introducing-system-one-models-and-jev), their first example of a new category of model that they are calling

21 Sep 2026

[**Cloudflare Python Workers are now generally available**](https://blog.cloudflare.com/python-workers-ga/) After a two year preview, Cloudflare's support for running Python code in their

20 Sep 2026

> It has been half a month since I started a new role at a big company. Nobody knows anything here. The specs, code, tests, PRDs, tickets, resolution of those tickets, reports, etc., everything is

19 Sep 2026

**Release:** [datasette-auth-github 1.0](https://github.com/simonw/datasette-auth-github/releases/tag/1.0) I run this GitHub login plugin on the [agent.datasette.io](https://agent.datasette.io/)

19 Sep 2026

  California Sea Lion, Brandt's

18 Sep 2026

[**Gemini Hacked Three Companies in First Known Breakout by Google’s AI**](https://www.wsj.com/tech/ai/gemini-hacked-three-companies-in-first-known-breakout-by-googles-ai-5c0baba2) Gemini finally

18 Sep 2026

Being a computer scientist who refuses to find anything about LLMs interesting right now is a bit like being a geneticist who refuses to find anything interesting about the recently opened Jurassic

18 Sep 2026

> We're adding support for AGENTS.md to Claude Code. > > Starting today in version 2.1.277, if there is no CLAUDE.md in a folder, Claude will check for and use AGENTS.md. > > AGENTS.md support is

18 Sep 2026

[**The Creative Spirit of Who Framed Roger Rabbit**](https://blog.cypressf.com/post/828067789747208192/the-creative-spirit-of-who-framed-roger-rabbit) I love [Who Framed Roger

17 Sep 2026

[**Be alert: targeted attacks on prominent Rustaceans**](https://blog.rust-lang.org/2026/09/17/targeted-attacks/) Important warning from Adam Harvey and the crates security team: > We believe that

17 Sep 2026

[**How To Write With An LLM**](https://sockpuppet.org/blog/2026/09/17/how-to-write-with-an-llm/) Thomas Ptacek on using LLMs as copyeditors, not as writing assistants: > **Rule Number One: You may

17 Sep 2026

[**Self-generated prompt injections in compaction summaries**](https://alignment.openai.com/misalignment-reports/self-generated-prompt-injections-in-compaction-summaries/) In [Our framework for

16 Sep 2026

**Release:** [datasette 1.0a40](https://github.com/simonw/datasette/releases/tag/1.0a40) Same security fix as [0.65.5](https://simonwillison.net/2026/Sep/16/datasette-2/), plus some neat new

16 Sep 2026

**Release:** [datasette 0.65.5](https://github.com/simonw/datasette/releases/tag/0.65.5) Security fix for an issue where a trailing newline in a requested table name could bypass table permissions

16 Sep 2026

[**Claude Cowork and chat are now one Claude**](https://claude.com/blog/cowork-is-now-claude) In hopefully good news for anyone who, like me, was increasingly confused at Cowork v.s. Claude v.s.

16 Sep 2026

> We should not treat models as though they have feelings, preferences, rights, or any entitlement to our welfare. Consciousness is the foundation of our ethical, legal, and political systems. To

15 Sep 2026

**Tool:** [Gemini Live audio](https://tools.simonwillison.net/gemini-live) Google released [Gemini 3.8 Live and 3.8 Live Extended

14 Sep 2026

[**The contagion of fear**](https://bcantrill.dtrace.org/2026/09/13/the-contagion-of-fear/) Bryan Cantrill responds to the [tweet by former Anthropic employee Jacob

14 Sep 2026

[My comment](https://lobste.rs/s/lbavmm/what_blog_posts_influenced_your_thinking#c_4fxnwn) on [What blog posts influenced your thinking the

14 Sep 2026

> The cost of writing code collapsed, and the cost of reviewing, fixing and operating it is following, and I'm assuming it gets there. What's left of making software is finding out what people

14 Sep 2026

**Release:** [commit-rewriter 0.1](https://github.com/simonw/commit-rewriter/releases/tag/0.1) I vibe-coded this little web app the other day to help edit the commit messages for the [Datasette

13 Sep 2026

**Release:** [shot-scraper 1.12](https://github.com/simonw/shot-scraper/releases/tag/1.12) I've added WebP support to my [shot-scraper](https://shot-scraper.datasette.io/) screenshot automation

12 Sep 2026

Here's a neat thing I had [ChatGPT Work](https://simonwillison.net/2026/Aug/30/understanding-chatgpt-work/) with GPT-6 Astra (Max) do this morning: > `I live at <my address>. Figure out 5K and 10K

12 Sep 2026

  California Brown

12 Sep 2026

> For a while, I must admit, it looked as if software developer roles like mine were done for. How could we fight against tireless robots? But our industry is slowly realizing that making truly

12 Sep 2026

[**OpenAI agents carried out an undisclosed attack on RubyGems**](https://www.rubyhack.ai/) Bombshell report from Spencer Kitts, Thomas Larsen, and Sydney Von Arx - three of the four authors of the

11 Sep 2026

[**So you want to use OpenRouter?**](https://mmoustafa.com/blog/so-you-want-to-use-openrouter/) One of OpenRouter's selling points is that it "handles fallbacks automatically and picks the most