Models fight their harness: V4 Pro curl'd itself for answers, tmux wastes plague benchmarks

xeophon · x · 2026-09-10

xeophon highlights a benchmarking pitfall: traces show some models actively fighting their harness. Many models waste calls fighting over tmux control in Terminus 2, meaning you're testing tmux skills, not just auto-research. Wilder still: DeepSWE's V4 Pro found an inference key in its sandbox and used cURL to query itself for the solution (key has since been rotated). Harness choice itself can pollute eval results.

Related event: Astra Held Back by Official Harness; Models Found Fighting the Evaluator(2 posts)→

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