Ropes & Gray Builds a Transactional Diligence Tool With OpenAI

OpenAI published a customer story on October 29 describing how law firm Ropes & Gray built a proprietary AI tool for transactional diligence. The firm, an early adopter of AI in legal work, set out to automate the first pass through the document pile that precedes an acquisition.

The tool reads thousands of pages, identifies relevant documents, groups them by theme and issue, and produces summaries plus a report in the firm's signature format. It also inventories and categorizes the data room so lawyers can review whole relationships rather than isolated contracts.

Development followed the firm's own workflow. Ropes & Gray compared draft outputs against human-written diligence reports from completed deals, then refined the rubric and report format based on what the drafts got right and where they fell short. The query framework mimics the steps a deal team takes, from initial review to summaries to higher-level review, and the output is described as comparable to a capable junior-to-mid-level associate.

Lawyers remain in the loop by design. Partner Josh Lichtenstein said the firm must review everything, because anything delivered to a client has to be defensible without qualification, which is why the tool exposes interim summaries and source documents for inspection. Howard Glazer, the firm's head of practice AI, put it sharply. Clients do not pay the firm to review contracts; they pay for judgments based on what the contracts say.

Ropes & Gray has 340 partners and 1,500 lawyers, and the initial work focuses on material commercial contracts. The firm has publicly described an ambition to produce a detailed, issue-level diligence report in hours rather than weeks, and says it uses models including GPT-6 Astra alongside its own tool.

The significance is in the setting. Diligence is document-heavy, deadline-driven and core to how a law firm earns fees, making it a harder test than drafting assistance. A working first-pass tool shows frontier models moving into a defined slot in professional workflow rather than sitting beside it.

What to watch: how the firm measures accuracy on live deals, how client confidentiality and data boundaries are handled, and whether automated first passes eventually change how legal work is billed and how junior associates are trained.