OpenAI’s COBOL migration score has made a striking leap

This week, OpenAI put COBOL in the spotlight. It announced benchmark results suggesting its latest models are getting much better at migrating COBOL programs and building software in languages with less code and documentation for models to learn from. On OpenAI’s own COBOL migration test, GPT-6.1 Sol reached 86.6% accuracy at low reasoning effort, up from GPT-5.6 Sol’s 5.4%, while costing 39% less. At higher reasoning effort, the newer model reached 97.9%. But the evidence behind the two evaluations is uneven. OpenAI has not published the details of its evaluation of COBOL (“Common Business-Oriented Language”; the programming language that AI coding tools may help maintain or migrate). It has released the MultiLangBench setup and test suite on GitHub.