Knowledge catalogue
Anyone know if ChatGPT Codex (in the new ChatGPT desktop app) is a strict superset of ChatGPT Work? Liked if you're a software engineer who isn't intimidated by Git features is there any reason you'd
OpenAI insiders have indicated that differences between their products are purely UI-based rather than reflecting actual capability differences. This suggests that what may appear to be distinct produ
One of the most confusing aspects of GPT-5.6 is figuring out which model to use at which reasoning effort - sounds like Sol on Medium might be a good new default for coding work, if it's an upgrade fr
'We’re bringing chats and projects back into the sidebar in a more familiar and customizable way' - hopefully that means the ChatGPT app won't hide classic chat away in that weird little floating wind
With Atlas being retired in favor of the browser embedded in the ChatGPT app I wonder if the whole category of AI-enhanced browsers is coming to a close The security/privacy issues remain unsolvable I
... and if you want to see some of OpenAI's own pelicans they featured a 3D pelican riding a tricycle, bicycle, pony, and another pelican in their livestream this morning: https://www.youtube.com/live
Notes on GPT-5.6, which includes some interesting new additions to the API (programmatic tool calling and multi-agent in particular) - plus 18 pelicans for the 6 reasoning levels and 3 new models: htt
I've been letting Claude and GLT-5.5 write almost all of my commit messages recently, but I don't feel great about it 'omitting the higher-level framing needed to understand broadly what the code is d
Sometimes they DO attempt to do that but guess the rationale incorrectly, which is worse than not adding no a rationale at all I do try to link commits back to issues though, which are written by me a
I had Claude Fable 5 run a final review of the release using this prompt and it kicked up another four release blockers! https://simonwillison.net/2026/Jul/7/sqlite-utils-4/#claude-fable-5-helped-a-lo
I released sqlite-utils 4.0, the 124th release but the first major version bump since 3.0 back in 2020 I managed to keep things backwards-compatible all the way up to version 3.39 before the accumulat
Now I'm regretting having carefully blasted through 100% of my Fable allotment in time for being cut off at the end of today! (Presumably 'Wed 12:00 PM' means I get it back at noon on Wednesday, not a
Since this is a slightly backwards-incompatible change here's a detailed upgrade guide - which you can read, or feed into your coding agent and have it apply the upgrades for you https://sqlite-utils.
Somewhat humbling to have Claude Fable do a final review of some software that you're about to release and have it then find (and fix) FIVE release blockers, for an estimated (unsubsidized) cost of $1
'At least this felt ambitious until fable chewed through each of my requests like it was nothing...' @simonw I made this 3D video infographic explaining the AuthaGraph map projection, with population
I absolutely hate how I'm getting to be suspicious of ANY reply to my posts here, especially ones that pose a question, as they are so often from bot accounts If you're running a bot like this please
Simon Willison shares additional notes and commentary on his blog regarding judgment and decision-making processes. The post likely explores practical considerations or philosophical perspectives on h
Sent out my sponsors-only monthly newsletter for June, which means the May newsletter is now available here https://github.com/simonw/monthly-newsletter-archive/blob/main/2026-05-may.md - you can spon
The most interesting Fable tip I've heard so far is to let the model use its own judgement as much as possible I told it 'For all coding tasks use your judgement to decide an appropriate lower power m
Simon Willison discusses the relationship between understanding and participation, exploring how comprehension of a topic or system is fundamental to meaningful engagement or contribution. The blog po
I really like this 'understand to participate' framing of the cognitive debt problem when working with coding agents That's where another answer comes in: we can understand to participate. You can lea
I've been blogging a few of my Fable experiments today, most recently I had it more-or-less one-shot a CLI coding agent on top of my LLM Python library https://simonwillison.net/2026/Jul/2/llm-coding-
Simon Willison discusses an ambitious project involving Fable, likely covering current development priorities or technical challenges in the Fable programming language or related tools. The post appea
'You need a rich set of concepts in your mind to think creatively and fluently about how to move something forward.' It's never just one loop! A project is many, many loops with the agent. And the und
@_catwu @simonw and I will be doing a fireside chat about 'This year in Claude' from 12:30pm-1:30pm at AIE in Expo Stage 2. We'll be covering a really wide range of topics and I think it will be reall
I've added video support to my 'shot-scraper' browser automation tool - you (or your coding agent) can now create a storyboard YAML file and use that to record a video demo of new web application feat
Notes (and a Pelican) on Claude Sonnet 5 - the new tokenizer makes it ~1.4x more expensive for English, ~1.33x more expensive for Spanish but roughly the same price for Simplified Mandarin https://sim
We’ve received notice that the Department of Commerce has lifted export controls on Claude Fable 5 and Mythos 5. We'll begin restoring access tomorrow, and will share an update soon. We’re grateful to
Is it just me, or are today's LLMs less likely to default to building everything in React than they were last year? I used to have to say 'don't use React' in almost all of my frontend web dev prompts
Not sure if that's a change in default preferences from the models or just that I'm often prompting inside existing projects and the models know full well not to introduce React to a project that isn'
This statement is a critical analogy about dismissing learning curves in technology or professional contexts. Simon Willison uses the comparison to highlight how unrealistic expectations—assuming empl
Also not a great advertisement for a sandboxing product: @daytonaio effectively saying they don't trust the security of their product enough to expose the source code When the competition for sandboxe
Update: it's fixed! @simonw @ClaudeDevs @claudeai This is fixed — the egress proxy was incorrectly blocking git/gh reads to public repos that weren't attached to the session. Clones/fetches work again
Claude Code for web just started saying 'GitHub is blocked by egress policy', which is a big problem for me because most of my prompts there start with things like 'clone simonw/sqlite-utils to /tmp t
This entry references a Claude.ai coding session shared by Simon Willison, a well-known technology writer and open source developer, likely demonstrating a practical example of using Claude's code int
... and now you can buy your own! https://happy-pelicans.printify.me/product/29480311 Proceeds go to http://birdrescue.org, a local non-profit that rescues pelicans (among other birds) I printed a cus
Pamela rocks https://x.com/pamelafox/status/2069183465501921605 By popular demand, here's a lil store where you can buy your own: https://happy-pelicans.printify.me/product/29480311 I will donate proc
This post highlights an interactive web-based demo of the Moebius model, which users can test directly in their browser with approximately 1.3GB of model data downloaded locally. The tool appears to b
Pamela Fox created a custom t-shirt design referencing Simon Willison's Pelican benchmark, a technical tool or metric in web development or performance testing. She posted about it on X (formerly Twit
My parallel agent side-project today was having Claude Code port the new Moebius image pinpointing model to ONNX in order to run it entirely in the browser https://simonwillison.net/2026/Jun/22/portin
I just released the first release candidate for sqlite-utils v4, adding a migrations system (previously released independently as sqlite-migrate) and support for nested transactions: https://simonwill
Don't miss the exact text though: 'We’re changing Fable 5’s safeguards for frontier LLM development to make them visible' - make them visible means they're undoing the truly egregious (dare I say 'una
Simon Willison demonstrated Fable's pelican illustrations generated at different Claude API thinking effort levels, showcasing how increased computational investment affects output quality and cost. T
Wrote up my initial impressions of Claude Fable 5 - it has a big model smell: slow, expensive and capable of crunching through pretty much everything I threw at it https://simonwillison.net/2026/Jun/9
A TIL on using http://agentsview.io to calculate token spending with Claude Fable 5 despite that model not yet being included in the AgentsView pricing database https://til.simonwillison.net/llms/agen
BREAKING: Anthropic just dropped Claude Fable 5—this is Mythos, made safe for public release. It is the best coding model in the world. We've been testing it internally @every for the last week or so
I've had access to Fable for a bit. A genuine jump in capability, I could feed it a 15 page design document for a project and it would work for 9+ hours and deliver terrific results. But working with
That's both OpenAI and Anthropic with confidential S-1s filed with the SEC - Anthropic filed theirs on June 1st We recently submitted a confidential S-1. We expect it to leak so we’re just announcing
I may have finally found the Python-in-a-sandbox solution I've been looking for... here's my latest experiment, this time running MicroPython in WebAssembly inside my Python applications https://simon
This post demonstrates how to run MicroPython compiled to WebAssembly using the `uvx` tool with a simple command-line example that prints 'Hello world'. It showcases the ease of executing MicroPython
Uber reportedly now caps coding agents at $1,500/month per employee per tool - seems sensible to me, but it's also an interesting hint at the value Uber thinks these tools are providing https://simonw
Simon Willison reports that after updating Codex desktop, a previously unavailable feature or functionality has been restored, expressing gratitude to Philipps Spiess. This likely refers to a bug fix
Every month I publish the now-a-month-old previous newsletter so people can see what they're missing out on. Here's what you would have got a month ago covering what happened in LLMs in April: https:/
Simon Willison announced the release of a May edition of his sponsors-only newsletter, which is designed for supporters who prefer a curated summary format instead of following his daily blog posts. T
Excellent news, this was a mistake, it's coming back! https://x.com/PhilippSpiess/status/2061189796689494339 @simonw Sorry about this! The button was unintentionally removed during some recent menu re
This post discusses concerns about automatic updates to Codex Desktop and the risk of losing important features in newer versions, reflecting broader anxieties among users about software upgrades remo
@simonw Sorry about this! The button was unintentionally removed during some recent menu restructurings. It'll be back with the next hotfix release. You can bind a custom keyboard shortcut to the 'Cop
Anthropic's self-reported run-rate revenue growth is wild - Axios @JimVandeHei said he could not find 'any company — in any industry, in any era — that has scaled organic revenue this quickly at this
Here's an extended edit of the quote that includes a following fragment where Andrew Macdonald called the trade 'harder to justify' - full, unedited transcript is here: https://gist.github.com/simonw/
Simon Willison expresses skepticism about reports claiming Uber overspent on AI and was disappointed with the results, indicating he investigated the story and found issues with its accuracy or framin