Simon WillisonSunday · July 5, 2026FREE

sqlite-utils 4.0rc2, mostly written by Claude Fable (for about $149.25)

Simon Willison announced sqlite-utils 4.0rc2, noting that the majority of the code was written by Anthropic's Claude Fable model for approximately $149.25. In a blog post, he described using Claude Code on his iPhone to perform a final review before shipping a stable 4.0 release. The model identified five "release blockers," the most severe being a bug in Table.delete_where() that never committed transactions, leaving the connection in an in_transaction state and causing subsequent writes to be lost. Willison reproduced the issue, confirming that after calling delete_where(), the connection's in_transaction flag remained True, and subsequent inserts and table creations were silently discarded upon closing the database. Over 37 prompts and 34 commits, Fable and Willison addressed all feedback, including improvements to transaction handling. The new RC includes comprehensive documentation on the transaction model, stating that every write method runs inside its own transaction and commits before returning. Willison also noted that db.atomic() and automatic per-method transactions are not supported with Python 3.12+'s autocommit parameter, as those connections behave differently. Finally, he had GPT-5.5 review Fable's changes, which uncovered a side effect in db.query(): it auto-commits write statements before raising a ValueError for non-row-returning SQL, contradicting its documented behavior.