Same model scores 24% vs 59% across harnesses, Chamath declares leaderboards worthless

eliano · x · 2026-10-13

Chamath argues model benchmarks are largely worthless: the same model can score 24% or 59% on the same 113 coding tasks depending on the harness wrapping it. He had 8090 Labs evaluate 7 models across 5 harnesses on real bug fixes and features from open-source projects, measuring the model-plus-harness pair.

Surprising results include Claude Fable 5.1 scoring 41% inside Claude Code but 61% inside OpenAI's Codex, with a median of 28 tool calls. He says he increasingly ignores leaderboard results since ranking gains don't show up in real work.

The post also quotes Palantir CTO Shyam Sankar: benchmarks measure something real, but not the tasks enterprise customers actually need solved.

Related event: Same Model, Different Harness: Benchmark Scores Swing by 35 Points, Chamath Says Leaderboards Are Meaningless(2 posts)→

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