OpenAI Unveils GPT-6 Astra Legal Model for Am Law 200 Firms
OpenAI launched Astra for Law, a GPT-6 model specialized for legal work, on September 17, 2026.
Why it matters: Legal professionals and tech vendors gain a powerful AI tool optimized for legal research and drafting to boost productivity and innovation.
- Astra for Law integrates GPT-6 Astra with a legal search index spanning over 230 million URLs.
- Index includes U.S. case law, statutes, regulations, court rules, and administrative decisions, updated daily.
- Developed with Am Law 200 firms like Sullivan & Cromwell, Ropes & Gray, and Cooley to ensure relevance.
- Passed 54% of a 200-question legal benchmark, outperforming the base GPT-6 Astra's 38.7%.
- Initially available via a Trusted Access program to select U.S. law firms, with broader API access planned.
On September 17, 2026, OpenAI unveiled Astra for Law, a version of its GPT-6 Astra large language model configured specifically for legal research and drafting tasks.
The model couples GPT-6 Astra's capabilities with a dedicated legal search index that spans over 230 million URLs, including U.S. case law, statutes, regulations, court rules, and administrative decisions. This index sources case law from the Free Law Project's CourtListener database, covering more than 99.9% of published U.S. precedential cases, with updates performed daily to maintain currency.
OpenAI collaborated closely with prominent Am Law 200 firms such as Sullivan & Cromwell, Ropes & Gray, and Cooley during development, ensuring Astra for Law aligns with the needs of leading legal practices. The company described it as "a new foundation for law firms and legal technology companies to build AI products and workflows around their expertise."
In testing against a specialized 200-question private benchmark, Astra for Law passed 54.0% of questions compared to 38.7% for the baseline GPT-6 Astra using web search alone, reflecting its enhanced legal domain performance.
The product is currently offered through a Trusted Access program to selected U.S. law firms, with OpenAI planning to extend access via an API in the future, potentially broadening availability to legal tech vendors and other organizations.
By the numbers:
- 230 million URLs — size of Astra for Law's legal search index
- 99.9% — coverage of published U.S. precedential case law by Free Law Project's CourtListener
- 54.0% vs. 38.7% — Astra for Law's vs. base GPT-6 Astra's pass rate on 200-question legal benchmark
What's next: OpenAI plans broader API access for Astra for Law, expanding availability beyond initial Trusted Access program.