Sprites.dev by @fly.io is a very cool new thing: it solves two of my pet problems at once, developer sandbox environments for coding agents and a JSON API for executing untrusted code I wrote more here: simonwillison.net/2026/Jan/9/s...

It's funny. I started my career in tech as a software tester, where I wrote tests for devs writing code. Now, a quarter of a century later, as I write unit tests and agent evals, my career will likely end as I write tests for... LLMs We all testers now! Suckit devs!?!

Normally the creators of beloved children’s cartoon characters would not need to disavow the U.S. Secretary of Defense, but ours is a drunken miscreant, a loutish boor with the dignity and nobility of a counterfeit butt-plug

Fifteen Years xkcd.com/3172/

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/...

joining the war on the dodgers. *sigh* on the side of canada

Before coffee: I hate everybody After coffee: I feel good about hating everybody

the US if Tylenol actually caused autism

just don't have time to vibe code this feature boss, I'm in too many meetings

Ah yes, raising $34.5B at $20B post to buy Chrome.

vibe coding is too manual. the new hotness is aura coding, where you just dress like a software developer but don't actually do anything

We are knee-deep in studying the developer experience around containers, because if agents are going to be maximally useful, they need to be in a box. What we have discovered so far: sketch.dev/blog/in-prai...

ZeroFS has a website now :)

America needs to take open models more seriously. Just this summer the early lead in open model adoption of Llama & co has been overtaken by Chinese models. With The American Truly Open Models (ATOM) Project we're looking to build support and express the urgency of this issue.

So now that the BLS is effectively useless and compromised, who are the data vendors most in position to publish approximately similar datasets 🤔

so good byteofdev.com/posts/making...

Right now Lean is very much the classic "first learn mathematics then learn Lean", but this hints at some interesting future, where mechanical proofs are approachable enough (at least at the basic levels) that it can be a way to teach proofs: adam.math.hhu.de#/g/leanprove...

The time to write your “why do people mourn when a famous person dies? People die all the time, your parasocial relationship with the dead person is illusory and illogical” skeet is immediately after you go back in time and hand your father a condom

Quitting programming as a career right now because of LLMs would be like quitting carpentry as a career thanks to the invention of the table saw.

So much wisdom that Gen. McChrystal shares in our interview. Lessons he's learned the hard way. What character & patriotism means, being on the front lines as your enemy uses new technology, how that tech is going to impact all of us. www.youtube.com/watch?v=ACGa... @cwclub.bsky.social

Can Claude Sonnet 4 write x86 assembly? I ran an experiment today and got Claude plus Claude Code to build, run and debug a pleasing Mandelbrot fractal in assembly, compiled via Docker on my Mac Full details, including prompts and Claude Code transcript, here: simonwillison.net/2025/Jul/2/m...

What voters think nativism will mean: stop giving benefits to others, so you can focus resources on citizens What it actually means in practice: stop giving citizens benefits, so you can focus resources on punishing others

One day I'll open a coffee shop dedicated to the not-insignificant intersection between database nerds and coffee snobs. Until then, enjoy this comic.

Microsoft open-sourced a sizable chunk of the GitHub Copilot VS Code extension today (MIT licensed) - I did some spelunking to try and find the LLM prompts that make it all work simonwillison.net/2025/Jun/30/...

If your tech optimism doesn’t make room for existential dread, you’re not paying attention. But if your pessimism doesn’t make room for existential astonishment, you’re missing the plot. We are apes with code. That can be terrifying. It can be transcendent. It’s OK if it’s both.

Whipping up a little summer treat:

I’m very happy with this poster the @tigerbeetle.com team made for my #ducklake talk today at #systemsdistributed - make it so!

Some recent experiences programming with agents. crawshaw.io/blog/program...

so good! fly.io/blog/youre-a...

Welcome to the age of $10/month Lakehouses! How to build and run a Lakehouse on top of @cloudflare.social R2 , Cloudflare Containers and Neon Postgres, all backed by the new DuckLake "SQL as Lakehouse" format, via @duckdb.org. tobilg.com/the-age-of-1...

[Karoline Leavitt saying the Librarian of Congress was fired for having books in the library] Wow that's the worst thing I've ever seen *refreshes feed* [The mayor of Newark is being held at an unspecified facility] Wow that's the worst thing I've ever seen

CEO of Nabisco criticizes Cookie Monster

LEGO OLENNA TYRELL IN 2030 GAME OF THRONES REBOOT VOICED BY CHRIS PRATT IN THE STYLE OF MARIO: tell cersei. i want her to know it was-a me

now you’ll have time to work on your serve, dillon #dubnation

Whoa

"Who would like to supervise the Claude agent who will be implementing this task?" -- me just now in eng planning

Two new books have been announced that, embarrassingly for the authors and publishers, fail spectacularly to understand what the term "vibe coding" means. The whole POINT of vibe coding is that you don't need to be a software engineer to do it. simonwillison.net/2025/May/1/n...

Chess Position xkcd.com/3082

LLMs have use cases for skilled people. I know a Principal Engineer building internal convoluted tooling that produces actual results. Of course they're building it for us, for our tooling suite, on our datasets they're an expert in, for moonshot early attempts at figuring out what's happening.

every day without a Pope is another knife shoved directly into my skull . this is kony 2012 all over again

put differently, you can count on AI to automate boilerplate and toil, but if you think AI is going to solve your hard problems, you’ll be disappointed AI coding done well forces you to think more, not less

The most important thing for you to know as a software engineer is that if you destroy the computer with a hammer it cannot hurt you anymore

I don't know who needs to hear this but you shouldn't vibe code changes to coredns in the production k8s cluster

The killer app for AI is turning meetings that should have been an email into an email.

📈 How large can DuckDB scale with its out-of-core capabilities? We have been testing DuckDB with the TPC-H queries on increasingly large scale factors and found that all 22 queries completed on the scale factor 100 000 data set – equivalent to 100 TB in CSV format – on a single AWS EC2 instance.

Yesterday I spent a few hours coding with the new OpenAI Codex CLI. The tool does all its file writes by using patch commands with diffs in the command line. Which is weird. I used it for 4 hours then used Claude Code to fix what it built :) help.openai.com/en/articles/...

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