A dedicated index of case law, statutes, and court decisions powers a new legal specialized version of the GPT-6 Astra model to increase the accuracy of professional research. OpenAI reports a 54% correctness rate on 200 legal research questions, up from 38.7% when using web search alone. The system includes a specific gpt-6-astra-law API endpoint to separate professional legal workflows from general model interactions and searches more than 230 million U.S. legal URLs with new sources added daily.

The offering integrates 26 partner plugins from providers including Thomson Reuters, Relativity, and Clio, alongside native integrations with Harvey and Legora. Law firms Sullivan & Cromwell, Ropes & Gray, and Cooley built custom agreement analyzers and IPO preparation systems using the tool. Access is initially limited to selected firms through Trusted Access in ChatGPT and Codex, with API access for broader builder use scheduled for later.