Lawyers have been burned by chatbots that invent case citations. OpenAI’s answer, launched on September 17, is a version of its GPT-6 Astra model that has been pointed at a legal library and told to behave like a researcher.
It is called Astra for Law. OpenAI describes it as GPT-6 Astra combined with legal-specific settings, tools, context and a legal search index, and it is offered to law firms and to the software companies that build for them. The model itself, released on September 3, is not new. The search layer is what changes what a lawyer gets back.
What it searches
The index is built to find US case law, statutes, regulations, court rules and administrative decisions. “The index covers more than 230 million URLs, with sources added daily,” OpenAI said. A partnership with the Free Law Project gives the system a case-law collection covering more than 99.9 per cent of published US precedential case law.
The company also says it is set up for analysis and writing. It can work from client facts, develop arguments or deal terms, and flag weak spots and uncertainty. In one example OpenAI gave, it can separate a court’s actual holding from the judge’s other remarks and spot cases that undercut an argument.
The numbers, and who ran them
OpenAI tested the product on 200 questions from the private validation set of Vals AI’s Legal Research Bench. At the highest reasoning setting, Astra for Law passed the overall correctness check on 54% of them. GPT-6 Astra with web search alone managed 38.7%. On case-law questions it turned up 24% more reference cases, and on an audited set of target passages it pulled up to 54% more of the relevant text from the right opinions.
These are OpenAI’s own results. The Cryptonomist noted that nobody outside the company has verified them yet.
Who gets it, and when
Access starts small. Selected firms get it through a Trusted Access program, with privacy controls that include zero data retention. An API version comes later. Harvey and Legora, both legal technology companies, are named as API customers who will build on it. Twenty-six plugins launched alongside, linking ChatGPT to tools law firms already use, among them Relativity and Clio. Others in the list include iManage, DeepJudge and Thomson Reuters.
OpenAI is aiming at the AmLaw 200, the 200 largest American law firms. Jason Boehmig, who leads legal product at the company, told a press briefing that “lawyers like longer responses,” and that Astra for Law’s answers run about twice as long as typical Astra replies. Sherwin Wu, a member of technical staff, said grounding the model in “actual case law” meant fewer hallucinations.
The launch landed in a crowded week. Thomson Reuters said earlier in September that it is developing its own legal and compliance language model, already used in the Tabular Analysis feature of CoCounsel Legal. Anthropic, which had pushed into legal AI in May, was reported by Reuters to be weighing a new model of its own. What the API version costs, and when it ships, has not been announced.
Sources
- OpenAI's Astra for Law: What its AI push for legal sector means for rivals | World News – Business Standard
- OpenAI Legal AI Launches Astra for Law in US Market
