Opus 5.5, GPT-6.1 Sol and Terra: What the Published Comparisons Show

Anthropic’s Claude Opus 5.5 and OpenAI’s GPT-6.1 Sol and GPT-6.1 Terra are positioned for overlapping but distinct workloads, and their published evaluations do not establish a single overall winner. The comparison depends on the task, reasoning setting and cost measure; the available materials provide benchmark results for each model, not a common head-to-head test of all three.