Fast mode research preview available for Claude Opus 5.5 on the Claude API

PreviewSep 22, 2026VerifiedAdded Sep 22, 2026

Fast mode, in research preview, can now be used with Claude Opus 5.5 on the Claude API.

LLMs Developer tools

Read Anthropic's release notes

https://platform.claude.com/docs/en/release-notes/overview#september-22-2026

Summaries of vendors' own notes. Product names and logos belong to their owners; logos via logo.dev.

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