blogmodel-release
Claude Opus 5.5 fast mode: GA without waitlist
Anthropic took Opus 5.5 fast mode out of research preview: set `speed: "fast"` (no beta header) for up to 2.5× OTPS at $8/$40 per MTok; separate rate limits; Claude Code `/fast` for interactive loops.
Claude Opus 5.5Claude APIClaude Code+1