Simon Willison — Independent developer and writer documenting practical experiments, tools, and deep analysis around large language models, generative AI, web development, security, and emerging programming workflows through detailed posts and daily TILs.
145 articles from this blog
A humorous anecdote about an AI-generated image of a horse riding an astronaut on a pelican on a bicycle, with a self-added sign.
A quote from Romain Huet confirming OpenAI won't release a separate GPT-5.5-Codex model, as coding capabilities are unified.
A guide on prompting GPT-5.5, including tips for multi-step tasks, migration advice, and starting fresh with new prompts.
Release notes for llm 0.31, a command-line tool for accessing large language models, featuring GPT-5.5 support and new options.
Analysis of why AI and automation are unpopular with the general public despite rising usage numbers.
DeepSeek releases V4 Pro and Flash AI models, offering frontier-level performance at significantly lower costs.
A tool to convert milliseconds to seconds and minutes, created by Simon Willison for LLM report durations.
Simon Willison's newsletter summary featuring tech posts on DeepSeek V4, LiteParse, and Agentic Engineering patterns.
Honker is a Rust SQLite extension implementing Postgres NOTIFY/LISTEN semantics for queues and streams.
Anthropic's postmortem on Claude Code quality issues reveals three bugs affecting user sessions, including a memory-clearing bug causing forgetfulness.
How a single Go process on a gaming PC powers Bluesky's For You feed for 72,000 users using SQLite and Tailscale.
A developer builds a browser-based version of LiteParse, an open-source PDF text extraction tool, using PDF.js and Tesseract.js.
GPT-5.5 is released via Codex; a new LLM plugin uses the semi-official backdoor API to access it through OpenAI subscriptions.
Release of llm-openai-via-codex 0.1a0, a plugin to access OpenAI models via Codex CLI credentials.
Qwen3.6-27B is a new open-weight model delivering flagship coding performance in a compact 27B dense model, outperforming larger predecessors.
Firefox CTO discusses using Claude Mythos Preview to fix 271 vulnerabilities in Firefox 150, highlighting security improvements.
GitHub Copilot Individual plans are changing with tighter usage limits, paused signups, and new pricing tiers due to increased compute demands from agentic workflows.
Analysis of Anthropic's confusing pricing test for Claude Code, moving it from $20 to $100/month plans.
Testing OpenAI's ChatGPT Images 2.0 with a Where's Waldo-style raccoon and ham radio prompt, comparing results across models.
A critique of AI agents being too human-like, lacking stringency and focus, arguing for less human-like behavior.
