Release Notes
Claude Sonnet 4.5 Now Available in Harvey
Harvey now supports Claude Sonnet 4.5, Anthropic’s latest reasoning model—optimized for code, numbers, and complex legal work.
What's New
We’ve added Claude Sonnet 4.5 to Harvey, offering you access to Anthropic’s most advanced reasoning model yet. With this release you can expect:
- Improved performance in code generation, research, and numerical reasoning
- Enhanced long-context reasoning for analyzing complex legal documents (for example, Credit Agreements)
Read our blog announcement to learn how Sonnet 4.5 compares to Claude's suite of models.
Why it Matters
Sonnet 4.5 delivers measurable gains in task completion, research, and legal document analysis, making it a powerful addition for workflows like deal management and due diligence. While we continue to evaluate the model against our other offerings, we're rolling it out now as part of our commitment to ensuring you have the best-in-class reasoning tailored to the rigor of professional services.
How to Use
Open Harvey’s Model Selector, then choose Claude Sonnet 4.5 when drafting, reviewing, or analyzing documents.
Limitations
Rollout is currently limited to eligible customers in the US and EU. If you cannot view the model and believe you should have access, please submit a support ticket.