Simon Willison

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…

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/ag…

Reached the stage of parallel agent psychosis where I've lost a whole feature - I know I had it yesterday, but I can't seem to find the branch or worktree or cloud instance or checkout with it in

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/sw…

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/ch…

What's the best model you can directly have a voice conversation with these days? I believe ChatGPT still switches to a 4o-class model for voice conversations, I'd be happy to be corrected on that

Coding agent users: do you run with --yolo (Codex) or --dangerously-skip-permissions (Claude Code) or equivalent?

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/cl…

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/be…

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/ge…

Claude Sonnet 4.6 really likes drawing top hats on its pelicans https://simonwillison.net/2026/Feb/17/cl…

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/ro…

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/co…

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

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/pr…

Shared some thoughts on http://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 http://ggml.ai, which kicked off the local model revolution back in March 2023 https://simonwillison.net/2026/Feb/20/gg…

I somehow missed that Claude Artifacts added persistent per-user and shared storage at some point in October - it's not in their release notes so I had to binary search the Internet Archive to figure out when it was added Anyone built anything neat with this that they can demo?

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/ro…

On the @oxidecomputer and friends podcast last month we (primary credit @ahl) 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/de…

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/op…