GPT-5.4 Now Available in Harvey

OpenAI's latest frontier model, GPT-5.4, is now live in Harvey, an AI platform purpose-built for legal teams. The integration brings meaningful improvements in substantive accuracy, drafting precision, and organizational clarity compared to the prior GPT-5.2 model.

Performance Improvements

Early access evaluations demonstrate tangible gains across legal workflows:

• Overall accuracy: 91.0% on Harvey's BigLaw Bench evaluation suite, up from GPT-5.2's 89.8%
• Perfect scores: Risk assessment and compliance tasks
• Standout areas: Deal management, drafting work, and litigation filing analysis
• Notable behavior: The model avoids preamble and filler text, diving directly into legal questions

Key Strengths for Legal Work

Harvey's Applied Legal Research team highlighted several practical advantages:

• Drafting-intensive work: Excels where attention to contractual detail is critical
• Speed and comprehensiveness: Fast analysis with strong underlying substance
• Organizational structure: Intuitive layout with appropriate levels of detail for legal documents
• Readability: Straightforward output that practitioners can quickly act on

Rollout Timeline

GPT-5.4 will be available in Harvey's model selector for eligible clients in phases:

• US and EU: Rolling out in the coming days
• Australia: Availability will be announced as regional capacity becomes available

Legal teams using Harvey can expect to leverage these improvements immediately for transactional work, contract analysis, and complex multi-step legal tasks requiring careful attention to detail.