sqlite-utils 4.0, now with database schema migrations

Simon Willison’s 124th release of sqlite-utils, and the first major version bump since 3.0 in November 2020. The headline feature is schema migrations, a sequence of changes to apply to a database plus tracking of which ones have already run. Nested transactions via a new db.atomic() context manager built on SQLite savepoints, and compound foreign key support, come with it.

The part worth remembering is how he tested it. He set frontier models loose on the pending changes: Claude Fable 5 wrote twelve Python scripts and turned up four release blockers plus ten further issues, and GPT-5.5 wrote another five. One of the issues it surfaced had been open since October 2020. The upgrade guide and the release notes were written entirely by Fable 5, Claude Opus 4.8 and GPT-5.5.

There’s no doubt in my mind that sqlite-utils 4.0 is a significantly higher-quality release than if I had built it without the assistance of the latest frontier models.