Lavern

Lavern is an open source multi agent legal system that runs on the user's own machine. A user types a request in plain language, such as reviewing a two year non compete across twelve states from the buy side, and a team of specialist agents picks up the work: reviewing, drafting, redlining, summarizing and restructuring documents. The system ships with 67 specialist agents, each with a defined skill set and persona, for example an M&A partner, an adversarial associate or a jurisdiction specialist, and users can build their own. Agents debate: every finding cites evidence and every challenge cites counter evidence, and an orchestrator weighs both and resolves the point, leaving an audit trail. Users can write a firm personality that is injected into every engagement so output follows house style. A knowledge layer indexes a dropped folder of precedents, contracts and memos and includes five public legal datasets, including CUAD, MAUD and LEDGAR. Each deliverable goes through a ten pass verification loop of critique and revision. It can run entirely on device, so documents stay on the laptop, or against frontier models. Lavern is released under the Apache 2.0 license and installs with a single shell command. Local mode costs $0, and the site notes that cost per engagement with hosted models depends on team size and document length. The project states that it is built in Helsinki, is not a real law firm, does not provide legal advice and is used at the user's own risk.