Long-Context Showdown: GPT-5.5 (74.0%) vs Claude Opus 4.7 (32.2%) on MRCR v2 8-Needle 512K-1M
Both models advertise 1M-token context. On the OpenAI MRCR v2 8-needle 512K-1M test, GPT-5.5 retrieves 74.0% vs Opus 4.7's 32.2%. Why context size and retrieval quality are different problems.