Claude Opus 4.8 fast mode will be removed on November 30, 2026
Anthropic's October 30, 2026 release notes deprecate fast mode for Claude Opus 4.8. It will be removed on November 30. After that date, requests to claude-opus-4-8 with speed: "fast" return an error. Anthropic says to move to Claude Opus 5.5 to keep using fast mode.
SessionWatcher editorial · Published · Updated · Source announcement: 2026-10-30
Related guide: How to check your Claude Code usage
What changed
Anthropic's release notes entry dated October 30, 2026 says fast mode for Claude Opus 4.8 is deprecated and will be removed on November 30, 2026.
After that date, requests to the claude-opus-4-8 model that set speed: "fast" will return an error instead of running. Anthropic says to migrate to Claude Opus 5.5 to keep using fast mode, and links to its Fast mode model availability page for details.
Sources: Anthropic release notes: 2026-10-30
What it means for your usage
Until November 30, fast mode requests to Claude Opus 4.8 work as before. From that date, any workflow that still asks Opus 4.8 for fast mode will get errors, so the work it was meant to do will not run. Switching those requests to Claude Opus 5.5 is the path the release notes give.
The entry covers only fast mode for Opus 4.8. It does not say that standard-speed Opus 4.8 is changing, and it gives no prices for fast mode on Claude Opus 5.5. It also does not say whether Claude Code or claude.ai plans are affected beyond API requests that set the speed parameter.
Sources: Anthropic release notes: 2026-10-30
AI assisted reporting, checked against the linked official sources. Source pages checked 2026-11-09. Editorial process and corrections.