Claude Opus 4.6 Now Available in Harvey

Harvey has made Claude Opus 4.6, Anthropic's latest frontier model, available to its legal AI platform users. The model builds on Opus 4.5's agentic capabilities with meaningful improvements across legal workflows, particularly in research-intensive work, due diligence, and complex transactional matters.

Performance Highlights

On Harvey's BigLaw Bench evaluation suite, Opus 4.6 achieved a 90.2% score — the highest for any Claude model to date. Key performance indicators include:

• 40% of tasks received perfect scores, demonstrating strong legal reasoning across both litigation and transactional practice areas
• Deal management, risk assessment, and corporate strategy tasks were standout performers
• Superior source grounding with one complex research query generating over 120 inline citations tied to specific source passages

Key Improvements

Early access testing revealed several substantive enhancements:

• Higher substantive accuracy with improved analytical depth on complex, multi-faceted legal questions
• Cleaner output formatting — the model resolves stylistic issues from prior Claude versions, eliminating unnecessary preamble text
• Thorough source grounding — citations are meticulously tied to specific passages in source material

Availability

Opus 4.6 is live for Harvey users now, extending Harvey's existing integration with Anthropic's Claude models. The model is positioned to handle the most challenging legal workflows where precision and source accountability are critical.