Counsel Stack "Top Performer" in Nation's Leading Independent Legal AI Research Study

Counsel Stack, the Pittsburgh-born startup and Brown and White Ventures portfolio company, outperformed every other legal AI startup to enter the nation's foremost independent legal research survey.

Those results were reported in the Vals Legal AI Report (VLAIR), which extended its original survey and evaluated how AI products perform on legal research tasks. It measured performance with respect to a lawyer control group, known as the Lawyer Baseline.

Counsel Stack joined early industry leaders Alexi, Midpage, ChatGPT and one other significant, unnamed company in the survey.

Vals reported: "Counsel Stack demonstrated strong performance across all evaluated criteria, achieving the highest scores among all participants with 81% accuracy, 77% authoritativeness, and 71% appropriateness, resulting in a 78% aggregate weighted score."

The Vals assessment measured the participants’ ability to respond to 200 U.S. legal research questions, distributed across a range of question types typically encountered in private practice.

The study established a scoring rubric taking into account prior studies and industry feedback. In the end, Vals evaluated responses using three weighted criteria.

· Accuracy: whether the response is substantively correct with no incorrect elements (50% of average weighted score)

· Authoritativeness: whether the response is supported by citations to relevant and valid primary and/or secondary law sources (40% of average weighted score)

· Appropriateness: whether the response is easy to understand and could be immediately shareable with colleagues or clients (10% of average weighted score

VLAIR reported that, based on evaluation results from its survey, Counsel Stack demonstrated several notable capabilities:

Highest overall performance: Achieved the top score across all three evaluation criteria (accuracy, authoritativeness, and appropriateness) among all participants in the study, including other legal AI products, generalist AI, and the lawyer baseline.

Superior accuracy: At 81% accuracy, Counsel Stack tied for the highest accuracy score, demonstrating strong capability in providing substantively correct responses with minimal misinterpretations or factual errors.

Strong source citation: Scored 77% on authoritativeness, leading all participants in identifying and citing relevant and valid primary law sources, an essential differentiator for legal AI products over generalist alternatives.

Comprehensive legal coverage: Successfully provided responses to 196 of 200 questions, with only 4 technical timeout issues, demonstrating broad coverage of U.S. legal research questions across federal and state jurisdictions.

Specialized LLM architecture: Built with multiple specialized LLMs specifically designed for legal research, enabling the product to handle the unique requirements of legal source identification and citation.

Consistent quality: Outperformed the lawyer baseline by 9 percentage points overall (78% vs 69%), demonstrating the ability to augment and enhance legal research capabilities for practicing attorneys.

Superior to generalist AI on sources: Achieved significantly higher authoritativeness scores compared to generalist AI products, reflecting the value of access to proprietary legal databases and specialized training on legal sources.

Founded in 2023, Counsel Stack offers multiple specialized LLMs for legal research, document review and client communications. In the VLAIR legal research study, their research product achieved the highest performance across all evaluation criteria, ranking first among all participants including legal AI products, generalist AI, and the lawyer baseline.

Brown and White Ventures made a $200,000 investment in Counsel Stack in 2025.