sqlite-utils 4.0rc2 was mostly written by Claude Fable — which caught a data-loss bug for $149.25
Simon Willison ran Claude Fable through 37 prompts and 34 commits to prep sqlite-utils 4.0 for a stable release, and the agent flagged a release-blocking bug he had missed: delete_where() never commits, poisoning the connection so later writes silently vanish on close. Willison paired it with GPT-5.5 as a cross-model reviewer that surfaced two more transaction-handling defects, at an estimated unsubsidized cost of $149.25 for 1,321 lines added across 30 files. The pattern that lands: one frontier model auditing another's diff now catches concrete correctness bugs, not just style, making cross-model review a practical guardrail for anyone shipping libraries with agents.
Source: simonwillison.net ↗
The connection is left in_transaction=True, so every subsequent atomic() call takes the savepoint branch and never commits either.
Why this matters
- → AI agents caught data-loss bug humans missed before stable release.
- → Cross-model review (Claude + GPT-5.5) surfaces transaction-handling defects reliably.
- → Practical guardrail for shipping production libraries with agent assistance.