Datasette 1.0a33 was built by splitting one feature across two frontier models.

Simon Willison released 1.0a33 on June 11, extending the ?_extra= JSON API to queries and rows. The build method is the interesting part: he planned with Claude Fable 5 in Claude Code and implemented with GPT-5.5 xhigh in Codex Desktop. One feature, two models, planning split from implementation. That's a concrete loopcraft pattern in the wild. The best planner isn't always the best implementer, and treating them as separate roles is a move I'm going to steal.