09.29.2025-day-0-support-for-claude-sonnet-4.5.md•579 B
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description: Available in Phoenix 12.1+
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# 09.29.2025: Day 0 support for Claude Sonnet 4.5 ⚡
{% embed url="https://storage.googleapis.com/arize-phoenix-assets/assets/images/claudesonnet45day0.mp4" %}
Phoenix now offers **day-0 support for Anthropic’s Claude Sonnet 4.5 model**. You can try it directly in the Playground UI, run experiments through the SDK, and evaluate with it using Phoenix evals. This ensures users can seamlessly adopt the latest Claude model without delays across all workflows.
{% embed url="https://github.com/Arize-ai/phoenix/pull/9700" %}