Simon Willison
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Quoting Jannis Leidel
GitHub’s slopocalypse – the flood of AI-generated spam PRs and issues – has made Jazzband’s model of open membership and shared push access untenable. Jazzband was designed for a world where the worst case was someone accidentally merging the wrong PR. In a world where only 1 in 10 AI-generated PRs meets…
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My fireside chat about agentic engineering at the Pragmatic Summit
I was a speaker last month at the Pragmatic Summit in San Francisco, where I participated in a fireside chat session about Agentic Engineering hosted by Eric Lui from Statsig. The video is available on YouTube. Here are my highlights from the conversation. Stages of AI adoption We started by talking…
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1M context is now generally available for Opus 4.6 and Sonnet 4.6
1M context is now generally available for Opus 4.6 and Sonnet 4.6 Here's what surprised me: Standard pricing now applies across the full 1M window for both models, with no long-context premium. OpenAI and Gemini both charge more for prompts where the token count goes above a certain point - 200,000 for…
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Quoting Craig Mod
Simply put: It’s a big mess, and no off-the-shelf accounting software does what I need. So after years of pain, I finally sat down last week and started to build my own. It took me about five days. I am now using the best piece of accounting software I’ve ever used. It’s blazing fast. Entirely local…
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Shopify/liquid: Performance: 53% faster parse+render, 61% fewer allocations
Shopify/liquid: Performance: 53% faster parse+render, 61% fewer allocations PR from Shopify CEO Tobias Lütke against Liquid, Shopify's open source Ruby template engine that was somewhat inspired by Django when Tobi first created it back in 2005. Tobi found dozens of new performance micro-optimizations…
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MALUS - Clean Room as a Service
MALUS - Clean Room as a Service Brutal satire on the whole vibe-porting license washing thing (previously): Finally, liberation from open source license obligations. Our proprietary AI robots independently recreate any open source project from scratch. The result? Legally distinct code with corporate…
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Coding After Coders: The End of Computer Programming as We Know It
Coding After Coders: The End of Computer Programming as We Know It Epic piece on AI-assisted development by Clive Thompson for the New York Times Magazine, who spoke to more than 70 software developers from companies like Google, Amazon, Microsoft, Apple, plus other individuals including Anil Dash, Thomas…
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Quoting Les Orchard
Here's what I think is happening: AI-assisted coding is exposing a divide among developers that was always there but maybe less visible. Before AI, both camps were doing the same thing every day. Writing code by hand. Using the same editors, the same languages, the same pull request workflows. The craft…
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Sorting algorithms
Sorting algorithms Today in animated explanations built using Claude: I've always been a fan of animated demonstrations of sorting algorithms so I decided to spin some up on my phone using Claude Artifacts, then added Python's timsort algorithm, then a feature to run them all at once. Here's the full…
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Quoting John Carmack
It is hard for less experienced developers to appreciate how rarely architecting for future requirements / applications turns out net-positive. — John Carmack, a tweet in June 2021 Tags: john-carmack, software-engineering, yagni
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AI should help us produce better code
Agentic Engineering Patterns > Many developers worry that outsourcing their code to AI tools will result in a drop in quality, producing bad code that's churned out fast enough that decision makers are willing to overlook its flaws. If adopting coding agents demonstrably reduces the quality of the code…
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Production query plans without production data
Production query plans without production data Radim Marek describes the new pg_restore_relation_stats() and pg_restore_attribute_stats() functions that were introduced in PostgreSQL 18 in September 2025. The PostgreSQL query planner makes use of internal statistics to help it decide how to best execute…
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Perhaps not Boring Technology after all
A recurring concern I've seen regarding LLMs for programming is that they will push our technology choices towards the tools that are best represented in their training data, making it harder for new, better tools to break through the noise. This was certainly the case a couple of years ago, when asking…
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Quoting Joseph Weizenbaum
What I had not realized is that extremely short exposures to a relatively simple computer program could induce powerful delusional thinking in quite normal people. — Joseph Weizenbaum, creator of ELIZA, in 1976 (via) Tags: ai-ethics, ai, computer-history, internet-archive
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Codex for Open Source
Codex for Open Source Anthropic announced six months of free Claude Max for maintainers of popular open source projects (5,000+ stars or 1M+ NPM downloads) on 27th February. Now OpenAI have launched their comparable offer: six months of ChatGPT Pro (same $200/month price as Claude Max) with Codex and…
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Quoting Ally Piechowski
Questions for developers: “What’s the one area you’re afraid to touch?” “When’s the last time you deployed on a Friday?” “What broke in production in the last 90 days that wasn’t caught by tests?” Questions for the CTO/EM: “What feature has been blocked for over a year?” “Do you have real-time error…
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Anthropic and the Pentagon
Anthropic and the Pentagon This piece by Bruce Schneier and Nathan E. Sanders is the most thoughtful and grounded coverage I've seen of the recent and ongoing Pentagon/OpenAI/Anthropic contract situation. AI models are increasingly commodified. The top-tier offerings have about the same performance,…
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Agentic manual testing
Agentic Engineering Patterns > The defining characteristic of a coding agent is that it can execute the code that it writes. This is what makes coding agents so much more useful than LLMs that simply spit out code without any way to verify it. Never assume that code generated by an LLM works until that…
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Clinejection — Compromising Cline's Production Releases just by Prompting an Issue Triager
Clinejection — Compromising Cline's Production Releases just by Prompting an Issue Triager Adnan Khan describes a devious attack chain against the Cline GitHub repository, which started with a prompt injection attack in the title of an issue opened against the repo. Cline were running AI-powered issue…
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Introducing GPT‑5.4
Introducing GPT‑5.4 Two new API models: gpt-5.4 and gpt-5.4-pro, also available in ChatGPT and Codex CLI. August 31st 2025 knowledge cutoff, 1 million token context window. Priced slightly higher than the GPT-5.2 family with a bump in price for both models if you go above 272,000 tokens. 5.4 beats coding…
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Can coding agents relicense open source through a “clean room” implementation of code?
Over the past few months it's become clear that coding agents are extraordinarily good at building a weird version of a "clean room" implementation of code. The most famous version of this pattern is when Compaq created a clean-room clone of the IBM BIOS back in 1982. They had one team of engineers reverse…
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Anti-patterns: things to avoid
Agentic Engineering Patterns > There are some behaviors that are anti-patterns in our weird new world of agentic engineering. Inflicting unreviewed code on collaborators This anti-pattern is common and deeply frustrating. Don't file pull requests with code you haven't reviewed yourself. If you open a…
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Something is afoot in the land of Qwen
I'm behind on writing about Qwen 3.5, a truly remarkable family of open weight models released by Alibaba's Qwen team over the past few weeks. I'm hoping that the 3.5 family doesn't turn out to be Qwen's swan song, seeing as that team has had some very high profile departures in the past 24 hours. It…
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Quoting Donald Knuth
Shock! Shock! I learned yesterday that an open problem I'd been working on for several weeks had just been solved by Claude Opus 4.6 - Anthropic's hybrid reasoning model that had been released three weeks earlier! It seems that I'll have to revise my opinions about "generative AI" one of these days.…
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Gemini 3.1 Flash-Lite
Gemini 3.1 Flash-Lite Google's latest model is an update to their inexpensive Flash-Lite family. At $0.25/million tokens of input and $1.5/million output this is 1/8th the price of Gemini 3.1 Pro. It supports four different thinking levels, so I had it output four different pelicans: minimal low medium…
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GIF optimization tool using WebAssembly and Gifsicle
Agentic Engineering Patterns > I like to include animated GIF demos in my online writing, often recorded using LICEcap. There's an example in the Interactive explanations chapter. These GIFs can be pretty big. I've tried a few tools for optimizing GIF file size and my favorite is Gifsicle by Eddie Kohler…
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February sponsors-only newsletter
I just sent the February edition of my sponsors-only monthly newsletter. If you are a sponsor (or if you start a sponsorship now) you can access it here. In this month's newsletter: More OpenClaw, and Claws in general I started a not-quite-a-book about Agentic Engineering StrongDM, Showboat and Rodney…
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My current policy on AI writing for my blog
Because I write about LLMs (and maybe because of my em dash text replacement code) a lot of people assume that the writing on my blog is partially or fully created by those LLMs. My current policy on this is that if text expresses opinions or has "I" pronouns attached to it then it's written by me. I…
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Quoting claude.com/import-memory
I'm moving to another service and need to export my data. List every memory you have stored about me, as well as any context you've learned about me from past conversations. Output everything in a single code block so I can easily copy it. Format each entry as: [date saved, if available] - memory content…
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Interactive explanations
Agentic Engineering Patterns > When we lose track of how code written by our agents works we take on cognitive debt. For a lot of things this doesn't matter: if the code fetches some data from a database and outputs it as JSON the implementation details are likely simple enough that we don't need to…
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