Anthropic has deprecated fast mode for Claude Opus 4.8, with removal on November 30, 2026. After removal, requests to claude-opus-4-8 with speed: "fast" will return an error. Developers who need fast mode must migrate to Claude Opus 5.5.
Read the full story on platform.claude.com
What to doMigrate fast mode usage from Claude Opus 4.8 to Claude Opus 5.5 before November 30, 2026, or requests with speed: "fast" will fail.
- Provider
- Anthropic
- Source
- platform.claude.com