AI article
Claude Opus 5.5 / Sonnet 5.5: 5 settings that return 400 when you only change the model name
Community description: Claude Opus 5.5 shipped on September 22, 2026 and Claude Sonnet 5.5 on September 28. If you take code...
Dev.to | Oct 15, 2026 | Pesimmoq
Automated excerpt
Sonnet 5. 5 replaces disabled with between_tools. Opus 5. 5 defaults to effort: medium (Opus 5: high). Official sources: Opus 5. 5 migration guide · Sonnet 5.
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