Fast mode for Claude Opus 5.5 leaves research preview, with no access request needed

ClaudeProduct changeConfirmed

Anthropic says fast mode is out of research preview for Claude Opus 5.5 and you no longer need to request access.

Requests no longer require the fast-mode-2026-02-01 beta header, and requests that still send it keep working.
Claude Opus 5.5 now has a default fast mode rate limit in the Start, Build, and Scale usage tiers; the limit numbers were not published in the note.
Fast mode is also available for Opus 5.5 on Claude in Microsoft Foundry for deployments hosted on Azure.

Who can use it: Claude API users on Claude Opus 5.5 in the Start, Build, and Scale usage tiers, plus Claude in Microsoft Foundry deployments hosted on Azure. Fast mode for Claude Opus 5 and Claude Opus 4.8 remains in research preview, and requests to those models must keep sending the beta header.
When: Announced October 15, 2026 in the Claude Platform release notes. Applies now.

Claude Platform release notes Announced 2026-10-15 · date only

Read the official announcement for access details. Availability can depend on your plan, region or workplace settings.

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