GPT-5.5 has become the first AI to achieve a perfect score on the ProgramBench binary rewriting challenge, a benchmark developed by Meta FAIR, Stanford, and Harvard. This challenge requires AI to reconstruct programs from compiled binaries without source code or hints. GPT-5.5, in high-reasoning mode, successfully recreated the cmatrix program in both C and Python, passing all tests at costs of $3.17 and $4.84, respectively. In contrast, Claude Opus 4.7 failed 19 tests despite higher costs and API calls. This achievement highlights the impact of reasoning intensity on AI performance, though full binary understanding remains a distant goal.