Code assistants write calls their users' Python version no longer has; a release-level record of 1,872 libraries lifts four models to 68.5%–69.9% repair success
Code assistants often emit Python calls that belong to an older release and no longer exist in the version a user has installed. PyPI API Drift statically extracts, without importing, the public APIs of 55,565 releases across the 1,872 most-downloaded libraries, recording signatures and release-to-release changes while separating true removals from names that merely left the documented API. In a preregistered code-repair experiment, four models from one family raised API-compatible, intent-preserving migrations to 68.5%–69.9% with this API history, against 7.0%–56.6% unaided.