When Claude Code Wrote a Full Database Engine Overnight: What ‘Ultracode’ Mode Actually Did
Reading Time: 5 minutesSimon Willison used Claude Code’s Ultracode mode — which coordinates parallel AI subagents for complex tasks — to produce a full SPARQL 1.1 SQLite extension in Rust overnight from a single typo-filled prompt. His account honestly surfaces the core tradeoff: agentic AI can now build at extraordinary speed, but the gap between ‘looks finished’ and ‘is trustworthy’ still demands expert review.