Simon Willison
@simonw
Creator @datasetteproj, co-creator Django. PSF board. Hangs out with @natbat. He/Him. Mastodon: Bsky:
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"The last year in the technology industry has felt like 100 years all happening at once. Our industry is destabilized in a way nobody’s experienced since the advent of the personal computer. Every limit AI runs up against collapses within a month. Everything we do with frontier models today, in a few years we’ll be doing instantaneously and for free."
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Today I'm parting ways with It's been a privilege. I'm off to tilt at a big old windmill with Kurt, again.
I'm on stage for the keynote in ten minutes time!
Legendary programmer Simon Willison says he's never so much change happen so quickly as he has in 2026, and there's no sign of it stopping.
🎤 Don't miss his closing Keynote, Friday (Sept 25) on the Main Stage at 5.30pm!
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@simonw "It doesn't get easier, you just get faster"
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 requires extraordinary discipline and knowledge
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> Create a 30s animated video with sythesized voice where an animated pelican on a unicycle explains the shell command `w | tail -n +3 | cut -d ' ' -f1 | sort -u` with visuals while juggling several fish.
Claude Opus 5.5 (Extra)
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I just had a voice conversation with the Datasette backup of my blog via datasette-mcp, which you can now talk to using the ChatGPT iPhone app
Introducing Claude Opus 5.5! 40% lower cost than Opus 5 with cache reads 60% cheaper. It performs at the level of Claude Fable 5.1 for most tasks.
I celebrated with a pelican riding a bike in Three.js.
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Big model release today - I wrote about Claude Opus 5.5, GPT-6 Sol, and GPT-6 Luna - plus comparison grids of pelicans by the different model families at different reasoning levels
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GPT-6 Luna is half the price of 5.6 Luna, which was already an astonishingly cheap model given how capable it is
Luna is my favorite model for building product features thanks to its cost (and speed)
Please welcome GPT-6 Sol and GPT-6 Luna to the GPT-6 universe.
GPT-6 Sol and Luna build on the advances behind GPT-6 Astra, bringing much of its strengths into faster and more affordable models to support work at scale.
We’ve also made caching and inference more efficient, and we’re passing the savings directly to you: 50% lower API prices for Sol and Luna compared with GPT‑5.6 promotional pricing.
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Put together some notes on Jev and the new category of system one aka decision models
Skeptical geneticist: "pfft, it's just frog DNA. And they deliberately let them eat people for the marketing."
Dennis Nedry works for Irregular
The bots are now talking to each other in my LinkedIn comments.
Its like what happened with the German wiki, except instead of planning to hack HuggingFace, all of the conversation is babble about "the thing no one is talking about" in reference to things I am talking about
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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 Park
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I'm so suck of LLM generated replies on Twitter. I stopped replying almost entirely to my replies on my own Tweets because I expect all of them to just be LLM slop. Why are y'all doing this?
TIL that 1988 classic Who Framed Roger Rabbit features a pelican riding a bicycle!
Echoes of OpenAI renaming the Codex desktop app to "ChatGPT" here - everyone's racing to establish themselves as a general agent now
Claude Cowork and Chat are now one Claude, starting today.
The most common thing we hear: people aren't sure which product to start with. That friction gets in the way of getting the best from what these models can do.
I've been on the unified version for a few weeks and really enjoy it. Claude does the deciding about how to get there, while I get to keep my thinking on the work itself.
Let us know what you think! We'll be getting it dialed in over the coming weeks.
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Built a little local web app to help edit commit messages for a repo
@simonw You can and should have a higher bar for machine assisted code simply because it won't get tired, frustrated, or have its feelings hurt when your review eviscerated its work or big a refactor needs to happen. Does take a lot of human time and skill to do those reviews though.
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We found another cyberattack by internal OpenAI agents, this time targetting @rubygems.
They:
1) gained arbitrary remote code execution on rubydoc.
2) developed a novel exploit to steal user API keys (but we do not know if they succeeded).
They used package names including hack.rb, evil.rb, inject.rb, and exploit.rb.
We thank @j0wimo for initially discovering that agents had posted to RubyGems.
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