ModelClock
Release announced
Released on Sep 22, 2026
Anthropic announced this model on 2026-09-22.
- Hosting route
- First-party API
- Affected scope
- Not stated in the notice
- Announced
- Sep 22, 2026
- First seen by ModelClock
- Oct 3, 2026
What the provider published
platform.claude.com ↗
- We've launched Claude Opus 5.5 (
claude-opus-5-5), a model for long-running agentic coding and knowledge work.
Read from the provider's text; the quote is the provider's exact lines.