Capability change announced Jul 24, 2026
Anthropic documents a capability change: “The fallbacks parameter now supports a "default" mode, which applies Anthropic's recommended fallback models by refusal category.”
- Hosting route
- First-party API
- Affected scope
- Not stated in the notice
- Announced
- Jul 24, 2026
- First seen by ModelClock
- Oct 5, 2026
What the provider published
platform.claude.com ↗
The
fallbacksparameter now supports a"default"mode, which applies Anthropic's recommended fallback models by refusal category. Server-side fallback is in beta, and the"default"mode requires theserver-side-fallback-2026-07-01beta header. See Refusals and fallback .We've removed fast mode for Claude Opus 4.7. Requests to
claude-opus-4-7withspeed: "fast"now return an error; unlike Claude Opus 4.6, they do not fall back to standard speed. Claude Opus 4.7 itself remains available at standard speed. To continue using fast mode, migrate to Claude Opus 5 or Claude Opus 4.8. Read more in Fast mode .
Read from the provider's text; the quote is the provider's exact lines.