Simon Willison — Week of 2026-04-11 to 2026-04-17#

Highlight of the Week#

This week’s most striking revelation came from Simon’s infamous “pelican riding a bicycle” SVG generation benchmark, where a 21GB quantized local model (Qwen3.6-35B-A3B) unexpectedly outperformed Anthropic’s brand-new Claude Opus 4.7 flagship. Running locally on a MacBook Pro via LM Studio, Qwen generated a better bicycle frame and even won a secret unicycle backup test, leading Simon to conclude that his joke benchmark’s long-standing correlation with general model utility has finally broken down.

Simon Willison — Week of 2026-04-18 to 2026-05-01#

Highlight of the Week#

The alpha release of llm 0.32a0 marks a foundational architectural pivot for Simon’s ecosystem of CLI tools. By moving away from a simple text-in/text-out abstraction to one that natively models complex message sequences and typed streams, the library is now future-proofed to handle the realities of modern frontier models. This opens the door for seamless integration of server-side tool calls, multi-modal inputs, and reasoning tokens.

Simon Willison — Week of 2026-05-08 to 2026-05-15#

Highlight of the Week#

The standout development this week is Simon’s rapid adaptation to the latest frontier model capabilities, most notably releasing llm 0.32a2 to expose and visualize the new interleaved reasoning tokens of GPT-5 class models directly in the terminal. This perfectly pairs with his hands-on explorations of embedding LLM calls deeply into developer workflows, such as executing prompts via script shebangs and leveraging models to output rich HTML rather than just Markdown.

Simon Willison — 2026-04-11#

Highlight#

The standout update today centers on the release of SQLite 3.53.0, where Simon highlights highly anticipated native ALTER TABLE constraint improvements and showcases his classic rapid-prototyping workflow by using Claude Code on his phone to build a WebAssembly-powered playground for the database’s new Query Result Formatter.

Posts#

SQLite 3.53.0 · Source This is a substantial release following the withdrawal of SQLite 3.52.0, packed with accumulated user-facing and internal improvements. Simon specifically highlights that ALTER TABLE can now directly add and remove NOT NULL and CHECK constraints, a workflow he previously had to manage using his own sqlite-utils transform() method. The update also introduces json_array_insert() (alongside its jsonb equivalent) and brings significant upgrades to the CLI mode’s result formatting via a new Query Results Formatter library. True to form, Simon leveraged AI assistance—specifically Claude Code on his phone—to compile this new C library into WebAssembly to build a custom playground interface.

Simon Willison — 2026-05-01#

Highlight#

Simon demonstrates the power of mobile AI-assisted development by building a complete, multi-component tracking application entirely on his phone while camping using Claude Code for web. It’s a perfect example of chaining small, sharp tools—Python CLIs, Git scraping, and AI-generated static frontends—into a highly practical personal utility.

Posts#

[iNaturalist Sightings] · Source Simon wanted to consolidate and view his iNaturalist observations across multiple accounts, grouped by when and where they occurred. To solve this, he used Claude Code for web to write inaturalist-clumper, a Python CLI that groups sightings within a 2-hour and 5km radius. He then set up a Git scraping repository to regularly run the tool and generate a clumps.json file hosted via GitHub. Finally, he prompted an AI against his tools repository to build a static HTML frontend that fetches the CORS-friendly JSON and displays the sightings in a gallery with lazy-loaded thumbnails and full-size modal images.

Simon Willison — 2026-05-15#

Highlight#

Simon’s latest AI-assisted project is a lightweight QR code generator built entirely with the help of Claude. It perfectly highlights his ongoing exploration of “vibe-coding” to quickly spin up practical, small-scoped utilities for everyday tasks.

Posts#

[QR code generator] · Source Simon used Claude to write a custom tool for instantly generating QR codes. The utility gracefully handles standard text and URL inputs, and also features a dedicated mode for generating QR codes that connect mobile devices to WiFi networks. It serves as another practical demonstration of using generative AI to rapidly build, iterate, and ship helpful little tools.