No Standard Harness: Hidden SDK Wrappers in LLM Evaluations
steipete · x · 2026-07-31
Regarding the practice of using a unified standard harness to evaluate LLMs, a developer revealed the underlying inconsistencies: there is actually no such thing as a native standard harness.
The so-called unified testing is actually configured via an SDK wrapper with per-model settings. For instance, Anthropic uses adaptive thinking equivalent to the Responses API, while OpenAI is set to the traditional Chat Completions style. These differences in underlying API call logic mean that cross-provider evaluations are rarely truly fair.
Related event: Developers Question LLM Evaluation Fairness Due to API Inconsistencies(2 posts)→
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