Using Claude Code: The Unreasonable Effectiveness of HTML
A member of the Claude Code team argues that requesting output in HTML from AI is more effective than Markdown, leveraging its rich interactivity and visualization capabilities to significantly enhance clarity and user experience.
Simon Willison · May 9, 2026
GPT-5.5 prompting guide
OpenAI's official prompting guide for GPT-5.5 emphasizes it is not a drop-in replacement for GPT-5.2/5.4, requiring a fresh start in prompt engineering for optimal results.
Simon Willison · Apr 25, 2026
Adding a new content type to my blog-to-newsletter tool
Simon Willison demonstrates an efficient prompt that enabled an AI coding assistant to complete a complex feature extension in one shot, revealing the core Agentic engineering pattern of 'explaining requirements with code'.
Simon Willison · Apr 18, 2026
Gemini 3.1 Flash TTS
Google's Gemini 3.1 Flash TTS is revolutionary because it uses detailed, screenplay-like prompts to precisely control emotion, accent, pace, and scene in speech synthesis, marking a shift from a 'tool' to a 'creative partner'.
Simon Willison · Apr 16, 2026