Claude Sonnet 5.5

Available · Language, Multimodal, Reasoning · Primary source available

Lifecycle
Milestone or variant
Related model
Source event
AI Radar coverage
Only month or year known
3 events

2026

As of 10 October 2026

Released +1Lifecycle · 28 Sep 2026

Predecessor Claude Sonnet 5Lineage · 30 Jun 2026

All events, in order

30 June 2026 Lineage Predecessor Claude Sonnet 5
28 September 2026 Lifecycle Released
28 September 2026 Source Announcement published

← The full record of Claude Sonnet 5.5, with every claim and its sources