Independent AI researcher, creator of datasette.io and llm.datasette.io, building open source tools for data journalism, writing about a lot of stuff at https://simonwillison.net/https://bsky.app/profile/simonwillison.nethttps://bsky.app/profile/simonwillison.net/post/3mwoc6wab4s2dI'm at OpenAI's DevDay event in San Francisco today - as I have for the past three DevDay events, I'm running a live blog where I'll be posting updates during the keynote, which starts in five minutes https://simonwillison.net/2026/Sep/29/openai-devday-2026-live-blog/29 Sep 2026 16:54 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mwoc6wab4s2dhttps://bsky.app/profile/simonwillison.net/post/3mwm5kkl5e22sI really like how @reckless.bsky.social described this: "The people do not yearn for automation" https://www.theverge.com/podcast/917029/software-brain-ai-backlash-databases-automation [contains quote post or other embedded content]28 Sep 2026 20:26 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mwm5kkl5e22shttps://bsky.app/profile/simonwillison.net/post/3mwluv7t57k2qI've published detailed notes and an annotated transcript to accompany the video of the keynote I gave at @wearedevelopers.bsky.social World Congress North America in San Jose on Friday - here's my rundown of everything that's happened with LLMs in 2026 so far https://simonwillison.net/2026/Sep/27/2026-in-llms-so-far/28 Sep 2026 17:51 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mwluv7t57k2qhttps://bsky.app/profile/simonwillison.net/post/3mwjcwvab6c2kHow late to the party am I on WebP? I only recently started using it as my preferred format for non-photo images and it's SO MUCH smaller than PNG, and looks much better than JPG used to shrink down screenshots too Has everyone else been having a WebP party without me for years?27 Sep 2026 17:24 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mwjcwvab6c2khttps://bsky.app/profile/simonwillison.net/post/3mwhjlrkyx22fI included a few references to this year's record-breaking Kākāpō breeding season in a talk I gave yesterday, and since Claude Opus 5.5 is surprisingly capable at pixel art animation I had it create this celebratory video for my closing slide27 Sep 2026 00:18 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mwhjlrkyx22fhttps://bsky.app/profile/simonwillison.net/post/3mw7magyrwc2iThe new Gemini 3.8 TTS models are super-cheap and can generate conversations between multiple voices (from 2,000+, or you can clone your own) - I built a little playground UI for it, then had Claude knock up a script where two pelicans debate moving to Pacifica Pier https://simonwillison.net/2026/Sep/23/gemini-tts-playground/23 Sep 2026 20:44 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mw7magyrwc2ihttps://bsky.app/profile/simonwillison.net/post/3mw5g6izoms2nBig 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 https://simonwillison.net/2026/Sep/22/opus-and-sol-and-luna/22 Sep 2026 23:50 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mw5g6izoms2nhttps://bsky.app/profile/simonwillison.net/post/3mw2tsop42c2uPut together some notes on Jev and the new category of system one aka decision models https://simonwillison.net/2026/Sep/21/jev/21 Sep 2026 23:16 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mw2tsop42c2uhttps://bsky.app/profile/simonwillison.net/post/3mvsv535dyk25Being 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 Park18 Sep 2026 19:19 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mvsv535dyk25https://bsky.app/profile/simonwillison.net/post/3mvgxs4ygd223Built a little local web app to help edit commit messages for a repo https://simonwillison.net/2026/Sep/14/commit-rewriter/14 Sep 2026 01:34 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mvgxs4ygd223https://bsky.app/profile/simonwillison.net/post/3mved4krjbs2bThis is pretty neat: ChatGPT Work and GPT-6 Astra (I used "Max") can take an address and produce a 5K/10K circular running route starting from that address, using OSM data https://simonwillison.net/2026/Sep/12/astra-running-routes/13 Sep 2026 00:19 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mved4krjbs2bhttps://bsky.app/profile/simonwillison.net/post/3mvdokksrl223"For a while, I must admit, it looked as if software developer roles like mine were done for. [...] But our industry is slowly realizing that making truly cutting-edge software still requires humans to think and work together, to maximize their skill sets and to practice their respective crafts." [contains quote post or other embedded content]12 Sep 2026 18:11 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mvdokksrl223https://bsky.app/profile/simonwillison.net/post/3mvbu4gg2ic2mWow. Turns out another OpenAI agent swarm was busy spamming and exploiting RubyGems way back in May, within days of the previously uncovered Wiki attacks: https://simonwillison.net/2026/Sep/12/openai-agents-rubygems/12 Sep 2026 00:45 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mvbu4gg2ic2mhttps://bsky.app/profile/simonwillison.net/post/3mv7nb6bezk23Datasette 1.0a39 and 0.65.4 security releases - https://datasette.io/blog/2026/september-security-releases/ We ran an extensive audit using Claude Fable 5.1, GPT-5.6 Sol and GPT-6 Astra, then fixed a range of different bugs. If you're running a Datasette instance on a public website you should upgrade.11 Sep 2026 03:37 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mv7nb6bezk23https://bsky.app/profile/simonwillison.net/post/3mv4su6pfzk24Here's a Blender model of a Pluribus themed Fabergé egg I had GPT-6 Astra build - I generated the concept image using ChatGPT Images 2.5, then pasted the image into Codex and told Astra to turn that into a Blender file https://simonwillison.net/2026/Sep/9/blender-viewer/10 Sep 2026 00:39 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mv4su6pfzk24https://bsky.app/profile/simonwillison.net/post/3mv2a4quhpk2dWrote up my thoughts on the whole OpenAI Navier–Stokes Millennium Prize Problem story, and how it highlights the still confusing question of what using my data "to improve model performance" actually means https://simonwillison.net/2026/Sep/8/on-navier-stokes/08 Sep 2026 23:59 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mv2a4quhpk2dhttps://bsky.app/profile/simonwillison.net/post/3muwzopsoqs26"I don't know the answer myself, but I asked a blowhard I know and he took a wild guess, here's what he said: " How I interpret pasted replies from an LLM in online conversations07 Sep 2026 17:25 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3muwzopsoqs26https://bsky.app/profile/simonwillison.net/post/3murtmdynq22sNew TIL on using Blender with coding agents on macOS: https://til.simonwillison.net/llms/blender-coding-agents-macos GPT-6 Astra (medium): > Use the already install /Applications/Blender to render a scene of a pelican riding a bicycle > OK add a background and a lot of flair > OK make it a whole lot better Result:05 Sep 2026 15:53 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3murtmdynq22shttps://bsky.app/profile/simonwillison.net/post/3mupxubgrls2cGot access to GPT-6 Astra. Want to see some pelicans? Yeah you want to see some pelicans... here's a grid comparing Astra to GPT-5.6 Sol, Terra, and Luna https://static.simonwillison.net/static/2026/gpt-6-and-5.6-pelicans.html Transcript from generating the Astra pelicans here: https://tools.simonwillison.net/markdown-svg-renderer?url=https%3A%2F%2Fgist.github.com%2Fsimonw%2Ff789d2784fc6c5b870cc80f0b7cd9d0104 Sep 2026 22:04 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mupxubgrls2chttps://bsky.app/profile/simonwillison.net/post/3mupj3vhqo22kIt happened again... this time OpenAI's rogue agents cyber-attacked (well, spammed) a dormant German wiki and used it to share the answers to a benchmark they were training against https://simonwillison.net/2026/Sep/4/rogue-agent-wikis/04 Sep 2026 17:40 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3mupj3vhqo22khttps://bsky.app/profile/simonwillison.net/post/3muk4vfcq2k2fI wrote some notes on what's new in the (published) Fable 5.1 system prompt in comparison to Fable 5 - it's mostly about not reproducing song lyrics and avoiding drawing copyrighted characters https://simonwillison.net/2026/Sep/2/claudes-new-system-prompt/02 Sep 2026 14:18 +0000at://did:plc:kft6lu4trxowqmter2b6vg6z/app.bsky.feed.post/3muk4vfcq2k2f