The Legal AI Data War From Fastcase That Redraws Licence Risk
Ben Thomson, LawFuel contributor
Clio-owned Fastcase has sued Canadian AI research platform Alexi in Washington, D.C., accusing it of turning a restricted data licence into a springboard for a rival AI legal research tool.
The complaint alleges Alexi used Fastcase’s licensed case law not just for internal research, but to train commercial generative AI models, display full‑text decisions to users, and even surface “View this document on Fastcase” buttons in its interface, implying an affiliation that never existed.
Fastcase claims breach of contract, trademark infringement and trade secret misappropriation, and seeks an injunction, destruction of trained models and disgorgement of profits. Alexi denies wrongdoing and says the licence was always intended to permit AI training.
What’s really at stake
There are some significant issues for law firms to be aware of with this case. Here are some of them –
AI training rights are not implied: The case underscores that “research” or “internal use” language will not safely cover training large‑scale commercial AI, especially where outputs re‑expose licensed content.
Your vendor can become your competitor: Fastcase’s claim that Alexi pivoted from memo drafting to a full-stack research rival illustrates how quickly data partners can transform into direct adversaries.
Model weights are now litigation targets: The request to destroy datasets and AI model weights shows courts will be asked to treat trained models as derivative works and potential trade secret repositories.
Lessons for legal tech
Law firms should demand precise AI clauses in vendor contracts, including training rights, output ownership, scope of “internal use”, audit rights and model‑deletion remedies.
Legal tech founders must assume that using third‑party legal databases for training without explicit, written consent is now a litigation‑grade risk, not a grey area.
Brand use is a separate liability lane and UI references to a data partner’s marks, even as navigation aids, can be framed as trademark use and implied endorsement.
The risks for legal tech and law firms identified in the Fasttrack case is something that lawyers and legal tech experts need to know – quickly. They can come at you fast, so be prepared.
