o1 vs Claude Sonnet 4

Compare o1 by OpenAI against Claude Sonnet 4 by Anthropic, in 2 community votes, claude sonnet 4 wins 100% of head-to-head duels, context windows of 128K vs 200K, tested across 23 shared challenges. Updated February 2026.

In 2 community votes, Claude Sonnet 4 wins 100% of head-to-head duels. Based on blind community voting from the RIVAL open dataset of 2+ human preference judgments for this pair.

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