OpenAI launches Astra for Law, a GPT-6 Astra foundation for legal work

OpenAI introduced Astra for Law on September 17, describing it as a foundation for law firms and legal technology companies that want to build AI products and workflows around their own expertise. The offering combines GPT-6 Astra, the company's most powerful model, with settings, tools and context tailored to professional legal work.

Existing API customers including Harvey and Legora will be able to build on the configuration, OpenAI said. Firms can adapt it with 26 new ecosystem plugins that connect ChatGPT to specialist tools they already use, such as Relativity and Clio, and the company is expanding its work on privacy and governance to give law firms controls for confidential client work.

From facts to a supported answer

The centrepiece is a legal search index that Astra for Law can use as a tool. OpenAI says the index covers US case law, statutes, regulations, court rules and administrative decisions across a corpus of more than 230 million URLs, with sources added daily. Work with the Free Law Project, the nonprofit behind CourtListener, brings a case-law collection covering more than 99.9% of published US precedential case law into the research experience.

To measure the effect, OpenAI tested the complete setup on 200 US legal research questions from the private validation set of Vals AI's Legal Research Bench. At the highest reasoning effort for both systems, Astra for Law passed the evaluation's overall correctness check on 54.0% of questions against 38.7% for GPT-6 Astra using web search alone — a 40% relative improvement. On case-law-focused questions it found 24% more reference cases, and on the audited set of target passages it retrieved up to 54% more relevant passages from the correct court opinions.

Analysis, drafting and controls

OpenAI also supplies instructions for legal analysis and writing, which guide the model in applying research to a client's facts, developing arguments or deal terms, and identifying weaknesses and uncertainty. Asked to find good law with similar fact patterns, the company said Astra for Law returned two closely matching precedents, while a competing model cited a holding that had been reversed on appeal.

For confidentiality, eligible firms enter through a Trusted Access programme that includes zero data retention on the API, with ChatGPT Enterprise usage excluded from human review by default. OpenAI said it is working with Latham & Watkins on information permissions, ethical walls, client instructions and firm oversight. Three firms have built internal systems: Sullivan & Cromwell an agreement analyzer, Ropes & Gray a deal diligence system and Cooley a capital markets application.

Availability

Astra for Law will initially be offered to selected law firms through Trusted Access in ChatGPT and Codex and will come to the API, where it appears as gpt-6-astra-law and in the model picker as GPT-6 Astra Law. The launch also includes 26 partner-built plugins, nine community plugins carrying 47 custom skills, and the general availability of ChatGPT for Word.