> ## Documentation Index
> Fetch the complete documentation index at: https://arizeai-433a7140.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# 09.29.2025: Day 0 support for Claude Sonnet 4.5

> Available in Phoenix 12.1+

<Update label="09.29.2025">
  <Frame>
    <iframe src="https://cdn.iframe.ly/8Pt0YVT4" className="aspect-video" allowfullscreen="" allow="encrypted-media *;" />
  </Frame>

  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.

  <Card title="feat: support Claude Sonnet 4.5 by anticorrelator · Pull Request #9700 · Arize-ai/phoenixGitHub" href="https://github.com/Arize-ai/phoenix/pull/9700" icon="github" horizontal>
    Github
  </Card>
</Update>