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I see a lot of complaints about untested AI slop in pull requests. Submitting those is a dereliction of duty as a software engineer: Your job is to deliver code you have proven to work

Simon Willison’s Weblog

Your job is to deliver code you have proven to work

In all of the debates about the value of AI-assistance in software development there’s one depressing anecdote that I keep on seeing: the junior ...

Here's my article on Gemini 3 Flash, with four pelicans (one for each of its thinking effort levels) plus an image gallery Web Component that I had Gemini 3 Flash build specially for this post

Simon Willison’s Weblog

Gemini 3 Flash

It continues to be a busy December, if not quite as busy as last year. Today’s big news is Gemini 3 Flash, the latest in Google’s “Flash” l...

Blogged some notes on the new ChatGPT Images model that launched today

Simon Willison’s Weblog

The new ChatGPT Images is here

OpenAI shipped an update to their ChatGPT Images feature - the feature that gained them 100 million new users in a week when they first launched it...

I ported a Python library implementing a full HTML5 parser to JavaScript using GPT-5.2 and Codex CLI in 4.5 hours, and decorated for Christmas and watched Knives Out while I was doing it

Simon Willison’s Weblog

I ported JustHTML from Python to JavaScript with Codex CLI and GPT-5.2 in 4.5 hours

I wrote about JustHTML yesterday—Emil Stenström’s project to build a new standards compliant HTML5 parser in pure Python code using coding age...

JustHTML by @npub1ukcz...r8n2 is a new Python library (no dependencies) that parses HTML according to the HTML5 specification and passes the 9,200 test html5lib-tests suite It's 3,000 lines of code mostly written by coding agents over a couple of months

Simon Willison’s Weblog

JustHTML is a fascinating example of vibe engineering in action

I recently came across JustHTML, a new Python library for parsing HTML released by Emil Stenström. It’s a very interesting piece of software, bo...