LLMs quietly flip constraints when they write optimization models: post-hoc repair lifts zero-shot accuracy from 44.8% to 64.9% without retraining the generator
OPT-Kraken treats an LLM's optimization model and solver code as frozen artifacts and repairs them after the fact, lifting zero-shot accuracy from 44.8% to 64.9% across six benchmarks while making only 0.6% of initially correct outputs incorrect.