Simon Willison

Given the recent burst of activity around enterprise pricing and contracts, I think April 2026 was the month when both OpenAI and Anthropic found product-market fit https://simonwillison.net/2026/May/27/product-market-fit/

I think Anthropic and OpenAI have found product-market fit simonwillison.net

Wrote up my initial impressions of Claude Fable 5 - it has a big model smell: slow, expensive and capable of crunching through pretty much everything I threw at it https://simonwillison.net/2026/Jun/9/claude-fable-5/

Initial impressions of Claude Fable 5 simonwillison.net

When I woke up this morning I didn't think I'd be spending a bunch of time today getting familiar with Catholic theology, but here we are. Notes on Pope Leo XIV's encyclical on AI. https://simonwillison.net/2026/May/25/encyclical-on-ai/

Notes on Pope Leo XIV’s encyclical on AI simonwillison.net

Uber reportedly now caps coding agents at $1,500/month per employee per tool - seems sensible to me, but it's also an interesting hint at the value Uber thinks these tools are providing https://simonwillison.net/2026/Jun/3/uber-caps-usage/

Uber Caps Usage of AI Tools Like Claude Code to Manage Costs simonwillison.net

My notes on Gemini 3.5 Flash - 3x the price of Gemini 3 Flash but Google are planning to use it for many of their own products https://simonwillison.net/2026/May/19/gemini-35-flash/

Gemini 3.5 Flash: more expensive, but Google plan to use it for everything simonwillison.net

I may have finally found the Python-in-a-sandbox solution I've been looking for... here's my latest experiment, this time running MicroPython in WebAssembly inside my Python applications https://simonwillison.net/2026/Jun/6/micropython-in-a-sandbox/

Running Python code in a sandbox with MicroPython and WASM simonwillison.net

It's now possible to compile Python extensions (C, C++, Rust etc) to WebAssembly and distribute them through PyPI such that Pyodide can install them directly https://simonwillison.net/2026/Jun/13/publishing-wasm-wheels/

Publishing WASM wheels to PyPI for use with Pyodide simonwillison.net

Notes on Claude Opus 4.8, which Anthropic call "a modest but tangible improvement" - plus pelicans riding bicycles for each of the five different thinking efforts https://simonwillison.net/2026/May/28/claude-opus-4-8/

Claude Opus 4.8: “a modest but tangible improvement” simonwillison.net

I don't have much to say about this year's Google I/O because I prefer to write about products that have shipped, not just "coming soon" announcements - but here are some notes on Gemini Spark and Antigravity https://simonwillison.net/2026/May/20/google-io/

Google I/O, Gemini Spark, Antigravity simonwillison.net

@slowenough I had it do a NORTH VIRGINIA OPOSSUM ON AN E-SCOOTER too - it made this: https://gist.github.com/simonw/68560eddb0b268a8417f80ceb7304dc6?permalink_comment_id=6172972#gistcomment-6172972 Pales in comparison to GLM-5.1 though https://simonwillison.net/2026/Apr/7/glm-…

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