# clm_D58BE2DA9452

subject: Claude Sonnet 4.5 (/record/claude-sonnet-4-5.md)  
predicate: model_release  
value: Sonnet 4.5  
valid_from: 2025-09-29  
valid_to: null  
published: 2025-09-29  
recorded: 2026-11-08  
confidence: 0.70  
status: valid  
assertable: true  
superseded_by: null  
last_updated: 2026-11-08  
cite: AsOf. "Claude Sonnet 4.5 model release: Sonnet 4.5", as of 2025-09-29. Claim clm_D58BE2DA9452, https://asof.is/claim/clm_D58BE2DA9452, accessed 2026-11-09. Source: https://support.claude.com/en/articles/12138966-release-notes#2025-09-29.  
checked: 2026-11-08 · its source page states the value and the date  

> September 29, 2025 Claude Sonnet 4.5 launch We released our newest model, Sonnet 4.5.

What https://support.claude.com/en/articles/12138966-release-notes#2025-09-29 says, word for word.

## Sources

- https://support.claude.com/en/articles/12138966-release-notes#2025-09-29 (primary, Anthropic, published 2025-09-29)

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