Made a new video demonstrating my process for upgrading a Datasette plugin using uv and an OpenAI Codex bash one-liner www.youtube.com/watch?v=qy4c... Here are detailed notes to accompany the video on my blog: simonwillison.net/2025/Nov/6/u...

I've been getting a lot of value using coding agents for code research tasks recently - I have a dedicated simonw/research GitHub repo and I frequently have them run detailed experiments and write up the results. Here's how I'm doing that + some examples: simonwillison.net/2025/Nov/6/a...

Achievement unlocked: caused Hacker News to have a 150+ comment argument about a TikTok joke (while I was asleep) news.ycombinator.com/item?id=4582...

Not the most interesting thing in here, but Datasette 1.0 should be out by the end of 2025!

Datasette 1.0a20 is out, with an entirely new SQL-powered permissions system. This is by far the most ambitious project I've attempted with the help of coding agents (Claude Code and Codex CLI) - notes on how it works and what I learned along the way: simonwillison.net/2025/Nov/4/d...

MCP Colors A riff off of the lethal trifecta for addressing prompt injection, this is a simple heuristic to ensure security at runtime red = untrusted content blue = potentially critical actions An agent can't be allowed to do both timkellogg.me/blog/2025/11...

I wrote up some notes on two new papers on prompt injection: Agents Rule of Two (from Meta AI) and The Attacker Moves Second (from Anthropic + OpenAI = DeepMind + others) simonwillison.net/2025/Nov/2/n...

Just sent out the October edition of my sponsors-only monthly newsletter - you can pay me $10/month to send you less! Here's the table of contents simonwillison.net/2025/Nov/1/s...

PyCon returns the to the US west coast in May I'd love to see some talks about how Python is used in the entertainment industry - if you know someone who works with Python in that space please encourage them to submit a talk!

My notes on CoreWeave's acquistion of Marimo - this year they also snapped up Weights & Biases, OpenPipe and Mammoth AI simonwillison.net/2025/Oct/31/...

MiniMax M2 is the new "most intelligent" open weights model (according to Artificial Analysis) - the MIT licensed weights are just 230GB and it appears comparable to Sonnet 4, while priced closer to Gemini 2.5 Flash. Notes here, including a new LLM plugin: simonwillison.net/2025/Oct/29/...

Notes on Cursor 2.0 and a pelican drawn by their brand new Composer-1 coding model, which they describe as "4x faster than similarly intelligent models" simonwillison.net/2025/Oct/29/...

The GitHub Universe badge this year is a full Raspberry Pi with a color screen and WiFi! I had a ton of fun hacking around with it yesterday, here are detailed notes on what I've built so far simonwillison.net/2025/Oct/28/...

This was a tough but necessary decision - I posted my own notes on this here, from the perspective of a current PSF board member simonwillison.net/2025/Oct/27/...

It's neat how if you ask Claude Code questions about itself it can answer them, because it knows how to fetch a Markdown index of its own online documentation and then navigate to the right place I wish more LLM tools would implement the same pattern! simonwillison.net/2025/Oct/24/...

Geoffrey Litt just proposed a new analogy for working with AI coding tools that I really like: you are the surgeon, staying in command and doing the most challenging work - the AI tools are your support team and surgical assistants simonwillison.net/2025/Oct/24/...

I recorded a ten minute video showing my vibe-coding process for building a tool for sharing formatted terminal sessions via copy and paste using the new Claude Code for web - now available on YouTube here www.youtube.com/watch?v=GQvM... More notes on my blog: simonwillison.net/2025/Oct/23/...

OpenAI's CISO Dane Stuckey posted an essay (on Twitter) about how their new ChatGPT Atlas browser attempts to deal with the risk of prompt injection attacks, I ended up writing a point-by-point commentary on my blog: simonwillison.net/2025/Oct/22/...

I gave a talk last night about "Living dangerously with Claude", on the joys and perils of --dangerously-skip-permissions and how critical it is that we run coding agents in a sandbox so that we can unlock their full potential simonwillison.net/2025/Oct/22/...

Just for fun, I had Claude Code figure out how to run the ~2001-era Perl and C SLOCCount program in WebAssembly in the browser, complete with a UI for counting source code lines from pasted text, a GitHub repository or a zip file simonwillison.net/2025/Oct/22/... Here's an animated demo

Wrote up my first impressions of ChatGPT Atlas, OpenAI's new browser - I remain unconvinced by the entire category of "browser agents", the security and privacy challenges still feel insurmountable to me simonwillison.net/2025/Oct/21/...

My notes on Claude Code for web, Anthropic's new asynchronous coding agent - I had preview access over the weekend, it's effectively a sandboxed instance of "claude --dangerously-skip-permissions" running in Anthropic's container simonwillison.net/2025/Oct/20/...

DeepSeek released a new OCR model - I got it working on an NVIDIA Spark (CUDA + ARM64) by starting a Docker container, running Claude Code as root with "claude --dangerously-skip-permissions" and telling it to figure it out Took 4 prompts and 40 minutes simonwillison.net/2025/Oct/20/...

Another banger from Singer Sound System, this time a cover of Bowie's The Man Who Sold The World on sewing machine powered hurdy-gurdy with attached theremin www.tiktok.com/@singersound...

New TIL: I spent some time exploring OpenAI's o4-mini-deep-research model via their Responses API and wrote up some notes on what I learned, including vibe-coding a few tools to help me evaluate the results til.simonwillison.net/llms/o4-mini...

The biggest problem with KPop demon hunters is that it exploded in popularity with not enough lead time left before Halloween for the Amazon supply chains to provide KPop demon hunter dog costumes (I want to dress Cleo up as Rumi but I don't have enough talent or diligence to pull it off in time)

This chap on TikTok has a 100 year old mechanical Dutch street organ and commissions new arrangements for it implemented as punched sheets - they're VERY good, here's Made You Look www.tiktok.com/@mechanicalm...

Claude Skills are awesome, maybe a bigger deal than MCP simonwillison.net/2025/Oct/16/...

My notes (and a pelican) for the new Claude Haiku 4.5 model, released by Anthropic this morning simonwillison.net/2025/Oct/15/...

Does widespread browser implementation of the Sec-Fetch-Site HTTP header mean we can protect against CSRF attacks without needing those hidden form tokens? It looks like the answer may be a cautious "yes"! simonwillison.net/2025/Oct/15/...

NVIDIA sent me preview hardware of their new DGX Spark 128GB ARM64 4TB "AI supercomputer" - it's a very neat little device, here are my notes so far simonwillison.net/2025/Oct/14/...

nanochat by Andrej Karpathy is neat - 8,000 lines of code (mostly Python, a tiny bit of Rust) that can train an LLM on $100 of rented cloud compute which can then be served with a web chat UI on a much smaller machine simonwillison.net/2025/Oct/13/...

Particularly good fingees today - "I added getting crushed by a vending machine to Minecraft" www.tiktok.com/@fingees_yt/...

Claude Code tip: prompt "use sub-agents" and it will do exactly that, firing up multiple parallel sub-agents to achieve a task, each with a fresh context "Write markdown documentation for the context passed to each of the templates in this project. Use sub-agents." simonwillison.net/2025/Oct/11/...

I'm beginning to suspect that a key skill in working effectively with coding agents is developing an intuition for when you don't need to closely review every line of code they produce. This feels deeply uncomfortable!

TIL Claude's new code interpreter mode has a /mnt/skills/public/ folder full of prompt instructions and Python utilities for creating and manipulating pdf, docx, pptx, xlsx files - and you can ask Claude for a copy and learn a TON about working with those formats simonwillison.net/2025/Oct/10/...

This is a wildly creative set of customizations for Claude Code, using the new plugin system they just released. There are SO many fascinating ideas in this! Strongly recommend reading it and then spending some time exploring the accompanying repo github.com/obra/superpo...

I figured out a uv recipe for running tests for any project with pyproject.toml or setuppy using any Python version: uv run --python 3.14 --isolated --with-editable '.[test]' pytest I've wrapped it in a uv-test script: uv-test -p 3.11 Full details here: til.simonwillison.net/python/uv-te...

Does anyone know of a RELIABLE tool for screen recording long sessions on macOS? I've been burned a ton of times by tools which seem great... and then they crash and lose the whole recording, or it turns out the audio wasn't recorded properly

This isn't exactly a surprise, but here's a note that Claude 4.5 Sonnet in Claude Code can write a full working Datasette plugin from a single prompt now simonwillison.net/2025/Oct/8/c...

What are some movies with the best opening 5-20 minutes? Two that come to mind for me: KPop Demon Hunters first five minutes (How It's Done on the plane) The first 20 minutes of Across the Spider-Verse, in Gwen's watercolor dimension (Both by Sony Animation Studios)

Python 3.14 is out today! Here are my notes on the new release: simonwillison.net/2025/Oct/8/p... If you're an open source library maintainer who supports all current Python releases this also means you can drop 3.9 support now and start depending on features from 3.10, like match/case

Just about to delete this post about Gemini 2.5 computer use solving its own CAPTCHA, I got this wrong - it tried to solve the CAPTCHA but it was Browserbase that actually solved it: simonwillison.net/2025/Oct/7/g...

Vibe coding is irresponsibly building software through dice rolls, not caring what code is produced What about when engineers at the top of their game use AI tools responsibly to accelerate their work? I propose "vibe engineering"! simonwillison.net/2025/Oct/7/v...

OpenAI released a new image gen model today - gpt-image-1-mini - which they describe as "80% less expensive than the large model" I vibe-coded a Python CLI tool to try it out. Here's "racoon eating cheese wearing a top hat, realistic photo" which cost ~0.2 cents simonwillison.net/2025/Oct/6/g...

I got the new GPT-5 pro API model to "Generate me an SVG of a pelican riding a bicycle". This pelican took 6m8s to generate and cost me $1.10! simonwillison.net/2025/Oct/6/g...

Decided to live blog this morning's OpenAI DevDay announcements, since I'm in the audience simonwillison.net/2025/Oct/6/o...

Inspired by your and Jesse's posts. Wrote how I'm using them in October 2025. heytaylor.dev/posts/202510...

Anyone running a large traffic site using that trick where you can tag pages and then tell your caching CDN to invalidate everything with a specific tag? Fastly calls it "surrogate keys", Cloudflare and Akamai call it "cache tags" Anyone got any success stories to share?

I've become one of those people who run multiple coding agents at once - here are my notes on embracing the parallel coding agent lifestyle simonwillison.net/2025/Oct/5/p...