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Anthropic · First-party API · LLM

claude-opus-4-6

Capability changeCapability change announced Jun 29, 2026
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Notice

Capability change

Capability change announced Jun 29, 2026

Anthropic documents a capability change: “June 29, 2026  We've removed fast mode for Claude Opus 4.6.”

Hosting route
First-party API
Affected scope
Not stated in the notice
Announced
Jun 29, 2026
First seen by ModelClock
Oct 5, 2026

What the provider published

platform.claude.com ↗

June 29, 2026

  • We've removed fast mode for Claude Opus 4.6. Requests to claude-opus-4-6 with speed: "fast" no longer run at fast speed or premium pricing: they run at standard speed, are billed at standard rates, and do not return an error. The response's usage.speed field reports the speed used. To continue using fast mode, migrate to Claude Opus 4.8 . Read more in Fast mode .

Read from the provider's text; the quote is the provider's exact lines.

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Same model elsewhere

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