Verdict
Claude Opus 5 leads 12–4 across 16 shared benchmarks.
Claude Opus 5 12 · Gemini 3.1 Pro 4 · higher isn't always better — check the caveats below.
Reported scores — protocols may differ. How we compare
Reasoning: Gemini 3.1 Pro leads 3–0 across 3 shared reasoning benchmarks (largest gap: SimpleQA Verified, 77.3 vs 56.7 — single evaluator).
Unknown: Claude Opus 5 leads 3–0 across 3 shared unknown benchmarks (largest gap: ProofBench, 99 vs 26 — single evaluator).
Math: Claude Opus 5 leads 2–0 across 2 shared math benchmarks (largest gap: FrontierMath-Tier-4-v2-Private, 73.17 vs 26.83 — single evaluator).
Vendor claims — compare against the measured scores above. A claim is what a developer says about its own model, not an independent measurement.
No vendor claims on file for Claude Opus 5.
Agentic / Tool Use
“Gemini 3.1 Pro was evaluated across a range of benchmarks, including reasoning, multimodal capabilities, agentic tool use, multi-lingual performance, and long-context.”
Multimodal
“a suite of highly capable, natively multimodal reasoning models”
Reasoning
“Gemini 3.1 Pro is Google's most advanced model for complex tasks.”
Claude Opus 5 leads 12–4 across 16 shared benchmarks. Claude Opus 5 leads 12 benchmarks and Gemini 3.1 Pro leads 4. Higher isn't always better — see the integrity caveats on each benchmark.
Claude Opus 5 and Gemini 3.1 Pro have 16 benchmarks in common in our data — those are the only rows where a direct, apples-to-apples comparison is drawn.
Gemini 3.1 Pro leads reasoning 3–0. Claude Opus 5 leads unknown 3–0.