#api

Claude Opus 5 API request parameters that now return a 400 error

Claude Opus 5 returns 400 on temperature. What to do

Set temperature=0.7 on Claude Opus 5 and the request fails. The API returns a 400 error, not a warning and not a silently ignored parameter. The same happens with topp, topk, and with the manual

Fri Aug 21 2026 · 6 min read · 0 views

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