normalizeXaiReasoningEffort() folded xhigh onto high before the request reached xAI, so anyone picking xhigh on grok-4.6 silently got high instead. xhigh is a real xAI tier (grok-4.6+); xAI already degrades it itself on unsupported models, so forwarding verbatim is safe everywhere. Closes#11816. Measured against live grok-4.6: reasoning_tokens 830 (high) vs 1052 (xhigh) — previously indistinguishable. Thanks!
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