claude-sonnet-4-5

Upstream reference: Claude Sonnet 4.5

Publisher: Anthropic

Anthropic introduced Sonnet 4.5 for coding, computer interaction and tool-using agents. Its launch article is a provider description rather than a Sigma5C capability finding.

Publisher-described context, separate from Sigma5C observations and recorded catalog statistics.

Published upstream specifications

Announcement date

September 29, 2025 Source

Publisher-described uses

• Coding and application tool workflows described by Anthropic. Source

Reference limitations

• A launch announcement does not establish current access or availability. Source

A recorded tag and an upstream card association do not verify the deployed checkpoint, quantization, configured context or current hosted availability.

Publisher sources

• Claude Sonnet 4.5 official documentation — Anthropic. Checked 2026-11-02.

Links

Recorded references do not establish downloadable weights, licensing or current availability.

• Anthropic — official site
• Provider page
• Official model announcement / documentation

Where claude-sonnet-4-5 comes from

Named in 1 observation page

• Codex vs Claude — native audit of a 425K LOC project · V1