OpenRouter Routing Bug: Fails to Pass Reasoning Effort, Degrading Model Performance

PawelHuryn · x · 2026-08-07

In a 105-bug benchmark, the author found that Meta's new model scored differently depending on whether it was accessed via the official API or OpenRouter (14 vs 17).

Investigation revealed that OpenRouter fails to correctly apply the reasoningeffort parameter. A simple validation involves sending a nonsense effort value: official APIs from Meta and xAI return a 400 error, whereas OpenRouter incorrectly accepts it.

Related event: OpenRouter Caught Dropping Inference Parameters, Distorting Model Scores(2 posts)→

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