Every frontier model in 2026 advertises a context window of at least a million tokens, but almost none of them are actually great at making use of all of that information. On MRCR v2, the multi-reference retrieval benchmark labs report, the best model is GPT-5.5, which scores 74.0%. Others like Claude Opus 4.7 at 32.2% are far behind. At this point, a million tokens seems to be the maximum for the context window that the major frontier labs are offering. One major reason for the million-token ma...