Anthropic releases Claude Opus 5.5
Anthropic released Claude Opus 5.5 (claude-opus-5-5): 1M context, 128k max output, always-on adaptive thinking, at $4/$20 per MTok (Claude Opus 5 is $5/$25). It is on the Claude API, Amazon Bedrock, AWS, Google Cloud, and Microsoft Foundry.
Models: Claude Opus 5.5
Source: Claude Developer Platform release notes, checked Sep 28, 2026. Summarized from the provider’s announcement.