The best LLM recommends the right replacement API 37.1% of the time.

Bridge mined 381,661 Java API update instances covering 18,900 mappings across 2,557 libraries, plus 277,259 Python instances, validated at 91.6% precision and 88.7% recall for Java (arXiv 2608.30497). Evaluated on replacement recommendation, the best model reaches 37.1% for Java and 44.4% for Python, doing markedly better on frequently observed mappings than uncommon ones. That is the memorization signature, and a direct warning for agent-driven library migrations against anything less than mainstream.