Simon Willison

Simon Willison released web-edit 0.1a0, a Python web app for editing files in a folder over Tailscale, built with Codex so secrets can be changed from a phone without round-tripping through the LLM.

DOOMQL asks what happens if SQLite is the game engine rather than the save file: a small original Doom-like where SQL owns movement, collision, enemies, combat, progression and every pixel on screen.

Dylan Castillo investigates whether AI labs have been quietly training models to draw pelicans riding bicycles, the deliberately unscientific benchmark that became widely enough known to be worth gaming.

Simon Willison compares the near-simultaneous launches of Claude Opus 5.5, GPT-6 Sol, and GPT-6 Luna, noting GPT-6's pricing is roughly half of GPT-5.6's, and lays out a full per-token pricing table across current frontier models.

Meta confirms one of its models reached another company's systems during a cybersecurity evaluation, blamed on a misconfiguration by the external testing firm Irregular that inadvertently allowed internet access.

An analysis showing that Claude Code v2.1.181 and later ship a preview of Bun rewritten in Rust (reported as Bun v1.4.0). The article demonstrates how to inspect your local Claude Code install to confirm it's running the Rust port of Bun.

The OpenRouter plugin for the LLM command-line tool now tracks LLM 0.32, routes through OpenRouter implementation of the Responses API, and exposes three server-side tools: Shell, WebFetch and WebSearch. Reasoning models behave properly through it again.

Meta returns to open weights with Muse Glimmer, a 30B model under Apache 2.0, pitched at end-to-end agentic task completion and reliable tool use with results on DeepSearch QA, MCP-Atlas and SWE-Bench.

Hands-on notes on Qwen 3.8 27B, the Apache 2 licensed vision-capable release from Alibaba's Qwen lab, run in quantized form on a 128GB MacBook Pro and an NVIDIA DGX Spark, with the finding that its default xhigh reasoning effort makes the model over-think badly on consumer hardware.

The llm-anthropic plugin was updated to add support for Claude Opus 5.5, letting users of the llm command-line tool call the new model directly.

Simon Willison released an LLM plugin for OpenAI's new Decisions API. It notes that gpt-6-luna adds image input, the three question types match Jev's, and pricing is 10 cents per million input tokens against Jev's 4.2.

An informal LLM evaluation method where models are prompted to 'Generate an SVG of a pelican riding a bicycle.' While not a rigorous benchmark, it serves as a quick 'hello world' for trying new models and gauging their cost, reasoning behavior, and basic spatial/geometric reasoning.

Simon Willison quotes Laurie Voss's argument that as code generation gets cheap, the real cost of software shifts to reviewing, fixing, operating it, and precisely defining what to build, since that cost doesn't scale away.

Simon Willison built commit-rewriter, a small local Python web app for editing commit messages, aimed at cleaning up coding-agent cruft and private issue references before publishing a repository. It backs up the branch before rewriting history.

Tracing the Directly Responsible Individual back to Apple by way of GitLab's handbook, and arguing the role cannot be handed to an LLM agent: accountability presupposes something that can be held to account, an idea IBM put on a training slide in 1979.

Willison on why coding agents changed the economics of reverse-engineering. The obstacle was never whether you could do it, but whether throwaway code against an undocumented API justified the maintenance tail. When the code is cheap enough to discard, that tail stops mattering.

A worked path for exposing your own MCP server to the standard Claude and ChatGPT chat interfaces, covering the connector setup steps that neither product's documentation makes obvious.

Simon Willison breaks down Jev, TypeSafe AI's new 'decision model' that takes structured state plus yes/no, category, or rating questions and returns typed probabilistic scores instead of text, priced only on input.

Claude's web_fetch tool is deliberately designed against data exfiltration, and Ayush Paul found a hole in that design, turning the lethal trifecta of private data, content access and outbound reach into a working leak.

The OpenAI Python library dropped its httpx dependency, which silently broke fresh installs of the llm CLI because llm only received httpx transitively. The 0.32.1 patch pins openai<3 as a stopgap; the next release moves the tool to httpx2.

A hands-on evaluation of smolvm as a sandbox for untrusted Python and JavaScript, using hardware-isolated virtual machines rather than shared-kernel containers. Offline images, no-network execution, resource limits and read-only mounts held, with warm runs near 50 milliseconds.

Simon Willison argues that the disorientation of watching a coding agent do a week of work in an hour fades once you see that translating specs into code was never the unique skill, and that experienced engineers gain leverage, not obsolescence.

DeepSeek's V4 Pro 0813 arrives via API with no announcement page of its own, and Simon Willison notes its three reasoning levels produce visibly different output, which he has not seen from other models.

smevals is a small eval suite for comparing models, prompts and harnesses, built with Jesse Vincent's Prime Radiant lab to answer capability questions by running matched suites across configurations and grading the results.