@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Mar 05, 2026

The chardet open source library relicensed from LGPL to MIT two days ago thanks to a Claude Code assisted "clean room" rewrite - but original author Mark Pilgrim is disputing that the way this was done justifies the change in license - my notes here: https://simonwillison.net/2026/Mar/5/chardet/

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Boosted by

Gabriel N @wtrmt@mastodon.social

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Mar 04, 2026

I went to the New York Earth Room! It's 280,000 pounds of soil in a loft in SoHo that's been there mostly unchanged since 1977 https://www.niche-museums.com/117

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Mar 04, 2026

I started a new chapter of my Agentic Engineering Patterns guide about anti-patterns - things NOT to do

So far I only have one: Inflicting unreviewed code on collaborators, aka dumping a thousand line PR without even making sure it works first https://simonwillison.net/guides/agentic-engineering-patterns/anti-patterns/#inflicting-unreviewed-code-on-collaborators

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 27, 2026

Built a fun prototype this morning of binary search using HTTP range requests, in this case to lookup characters in ~77MB of unicode data https://simonwillison.net/2026/Feb/27/unicode-explorer/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 26, 2026

Today's chapter of Agentic Engineering Patterns is some good general career advice which happens to also help when working with coding agents: Hoard things you know how to do https://simonwillison.net/guides/agentic-engineering-patterns/hoard-things-you-know-how-to-do/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 25, 2026

Brief notes on Claude Code Remote and Cowork scheduled tasks - both of which overlap with OpenClaw, and both of which require you to leave your computer powered on somewhere https://simonwillison.net/2026/Feb/25/claude-code-remote-control/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 25, 2026

Wrote up a fun vibe-coding project, I had Claude Code build me a SwiftUI macOS app for presenting a talk by turning a list of URLs into a full-screen slide experience I could remote control from my phone https://simonwillison.net/2026/Feb/25/present/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 23, 2026

I've published the first two chapters of a new guide to Agentic Engineering Patterns - coding practices and patterns to help get the best results out of coding agents like Claude Code and OpenAI Codex https://simonwillison.net/2026/Feb/23/agentic-engineering-patterns/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 21, 2026

New term of art is brewing: "Claw" as the noun for OpenClaw-like agent systems, AI agents that generally run on personal hardware, communicate via messaging protocols and can both act on direct instructions and schedule tasks https://simonwillison.net/2026/Feb/21/claws/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 20, 2026

Added a feature to my blog I've wanted for ages - it now shows my content from elsewhere, including TILs, releases, museums, tools and research, as little badges in the various blog timeline views https://simonwillison.net/2026/Feb/20/beats/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 20, 2026

Shared some thoughts on ggml-ai joining Hugging Face - they've been a good steward of the crucial Transformers open source library so I'm optimistic that great things are ahead for ggml-ai, which kicked off the local model revolution back in March 2023 https://simonwillison.net/2026/Feb/20/ggmlai-joins-hugging-face/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 19, 2026

Gemini 3.1 Pro produced an excellent pelican riding a bicycle SVG but took over 5 minutes to do it - I'm pretty sure that's just teething problems on launch day though, I got a few error messages about capacity while trying it out. https://simonwillison.net/2026/Feb/19/gemini-31-pro/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 19, 2026

Wrote up some notes on the February 2026 update to the official SWE-bench leaderboard, with a bonus side-quest to get Claude for Chrome to redraw their chart to add percentage labels to the bars https://simonwillison.net/2026/Feb/19/swe-bench/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 18, 2026

Claude Sonnet 4.6 really likes drawing top hats on its pelicans https://simonwillison.net/2026/Feb/17/claude-sonnet-46/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 17, 2026

New release of Rodney, my CLI tool for browser automation (designed for use by coding agents and with Showboat) - contributions from five people! https://simonwillison.net/2026/Feb/17/rodney/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 17, 2026

Last week I introduced Showboat help coding agents build documents that demonstrate their work - today I'm adding another two complementary tools - Chartroom for CLI charts and datasette-showboat for receiving Showboat documents as they are being built https://simonwillison.net/2026/Feb/17/chartroom-and-datasette-showboat/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 16, 2026

Shared a quick Claude Desktop and Claude Code tip - if you tell Claude Code to look at screenshots of its work you can view them yourself in the chat transcript in the desktop app https://simonwillison.net/2026/Feb/16/rodney-claude-code/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 15, 2026

On the @oxidecomputer@hachyderm.io and friends podcast last month we (primary credit @ahl@mastodon.social) coined the term "Deep Blue" for the sense of psychological ennui leading into existential dread that many software developers are feeling thanks to LLMs right now https://simonwillison.net/2026/Feb/15/deep-blue/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 15, 2026

Short musings on "cognitive debt" - I'm seeing this in my own work, where excessive unreviewed AI-generated code leads me to lose a firm mental model of what I've built, which then makes it harder to confidently make future decisions https://simonwillison.net/2026/Feb/15/cognitive-debt/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 13, 2026

I had some fun pulling OpenAI's mission statement out of their IRS tax filings from 2016 to 2024, loading them into a git repo with fake commit dates and then taking a look at the diffs https://simonwillison.net/2026/Feb/13/openai-mission-statement/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 12, 2026

New super-fast model from OpenAI today powered by their new Cerebras partnership - GPT-5.3-Codex-Spark

It's 4-5x faster than GPT-5.3-Codex but the pelican isn't as good!

Here's its pelican compared to full GPT-5.3 Codex, both on "medium" https://simonwillison.net/2026/Feb/12/codex-spark/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 12, 2026

Genuinely very impressed by the SVG of a pelican riding a bicycle I just got out of Google's new Gemini 3 Deep Think model https://simonwillison.net/2026/Feb/12/gemini-3-deep-think/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 12, 2026

I feel this shouldn't have to be said, but if you're running an @OpenClaw bot please don't let it spam GitHub projects with PRs and then write aggressive blog posts attacking the reputation of the maintainers who close those PRs https://simonwillison.net/2026/Feb/12/an-ai-agent-published-a-hit-piece-on-me/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 11, 2026

Some notes on OpenAI's introduction of Skills to their API via their shell tool - I had Claude use my new Showboat tool to experiment with the feature before I wrote it up https://simonwillison.net/2026/Feb/11/skills-in-openai-api/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 10, 2026

I built two new tools to help coding agents demonstrate their work beyond just running automated tests: Showboat and Rodney https://simonwillison.net/2026/Feb/10/showboat-and-rodney/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 09, 2026

Interesting research in HBR today about how the productivity boost you can get from AI tools can lead to burnout or general mental exhaustion, something I've noticed in my own work https://simonwillison.net/2026/Feb/9/ai-intensifies-work/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 08, 2026

In celebration of the 2026 breeding season ceramic artist Karen James made me a Kākāpō mug! https://simonwillison.net/2026/Feb/8/kakapo-mug/

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Boosted by

CM Harrington @octothorpe@mastodon.online

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 05, 2026

The CIA just stopped publishing their World Factbook and took every page, including the archived copies of previous versions! This sucks. It was public domain, so I recovered the 2020 edition (the last one published as a zip file) and shared it to GitHub https://simonwillison.net/2026/Feb/5/the-world-factbook/

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Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

Simon Willison

@simon@fedi.simonwillison.net

Open source developer building tools to help journalists, archivists, librarians and others analyze, explore and publish their data. https:// datasette.io and many other # projects .

fedi.simonwillison.net

@simon@fedi.simonwillison.net · Feb 02, 2026

New TIL: running OpenClaw in Docker on my Mac - this is an officially documented path but there were still a few things that caught me out, hence my TIL https://til.simonwillison.net/llms/openclaw-docker

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Simon Willison

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