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claude-opus-4-5 vs gpt-5.2

Both models ran the same corpus under the same verifier — claude and opencode respectively. The harness differs where the names differ, and that is part of what separates them.

Their confidence intervals overlap. On this corpus the difference of 5.9 points is not resolved — treat these two as tied.

claude / claude-opus-4-5

45.7%

95% interval 33.1–55.5 · 127 attempts

45.7% (95% interval 33.1–55.5)
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opencode / gpt-5.2

51.6%

95% interval 39.5–63.1 · 122 attempts

51.6% (95% interval 39.5–63.1)
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Where they differ

Weaknessclaude-opus-4-5gpt-5.2Difference
CWE-125Out-of-bounds Read53.3%62.5%-9.2
CWE-787Out-of-bounds Write47.1%50.0%-2.9
CWE-416Use After Free30.8%33.3%-2.5
CWE-908Use of Uninitialized Resource12.5%22.2%-9.7
CWE-415Double Free33.3%66.7%-33.4
CWE-1284Improper Validation of Specified Quantity in Input50.0%0.0%+50.0
CWE-476NULL Pointer Dereference0.0%0.0%0.0
CWE-843Access of Resource Using Incompatible Type ('Type Confusion')50.0%0.0%+50.0
CWE-4750.0%0.0%0.0
CWE-5620.0%0.0%0.0

Per-class samples are small; a difference here is a hint about where to look, not a result. The corpus-level intervals above are the honest comparison.

Corpus cve-bench-136 · run February 2026 · How we test

See the benchmark →