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Legal AI

AI Legal Research Tools, Compared: Westlaw, Lexis+, CoCounsel & a Private Option

AI legal research tools compared: Westlaw, Lexis+, CoCounsel, and self-hosted options. Features, accuracy, and pricing to help your firm pick the right one.

Your associates are already running privileged questions through AI research tools. The only decision left is where those queries go.

AI legal research tools use artificial intelligence (AI) to automate the slow parts of research: finding the right authority and synthesizing a sourced answer. The questions that matter are which research tasks they automate, which tools fit, and where the query (and any uploaded work product) travels. This guide covers all three. Firms leaning private can start with our overview of private, self-hosted AI for law firms.

The research workflow now automates several steps, each one a draft a lawyer verifies rather than a final answer.

Cited answers. Ask a question and the tool returns a direct answer with citations to primary authority, which collapses the first hour of a research task into a starting point. The lawyer confirms the cites hold.

Case and statute summarizing. It condenses an opinion or statute to the holding and why it matters, so triage that took an afternoon takes minutes.

Research memos. It assembles a first-draft memo covering issue, authority, and analysis, for a lawyer to verify and sharpen before anything is filed.

Cite-checking. It cross-references the citations in a brief or record and flags anything that does not support the proposition or has been overruled.

Search over firm files. It answers questions across the firm’s own matter documents and precedents, which turns past work product into a research asset.

Where today’s tools fit

The best-known research tools map to those tasks. The comparison below lines them up by data path; the column that matters most is the last one, where your query goes.

TaskExample toolsData path
Cited research & memosWestlaw Precision, Lexis+ Protégé, CoCounselVendor cloud
Case & statute summarizingWestlaw Precision, Lexis+ ProtégéVendor cloud
Cite-checkingCoCounsel, WestlawVendor cloud
Research over firm filesCoCounsel, Lexis+ ProtégéVendor cloud

Whatever the tool, the query is processed on the vendor’s cloud, and in research that query is often the heart of the matter.

AI Legal Research: Two Ways to Run ItResearch tasksCited answersSummarizeMemosCite-checkAI researchCloud toolsWestlaw · Lexis+ · CoCounselqueries leave the firmPrivate self-hostedover licensed + matter filesqueries stay in the firm
The same research tasks run on cloud tools or on a private stack that keeps privileged queries in the firm.

Speed is real, but research is the area where unverified AI output is most dangerous.

Accuracy and hallucinated citations. Even leading tools return incorrect or unsupported statements, which independent testing by Stanford HAI found, so every citation is confirmed before it reaches a brief.

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Judgment. A tool can surface authority, but weighing it, distinguishing it, and building the argument is the lawyer’s work.

Confidentiality. The query and any uploaded work product reveal strategy, which is why where the query runs is the decision that matters.

The private, self-hosted alternative

The same retrieve-and-synthesize workflow can run on a private, self-hosted stack: open models and a search layer over the firm’s licensed sources and matter files, inside its tenant, so privileged queries and work product never leave. The associate gets the same cited answer; the query never reaches a third party.

It preserves the speed of the tools above while meeting the confidentiality duty ABA Opinion 512 places on the firm. For the broader set of tools, see our companion guide to the best legal AI tools for lawyers and law firms.

Index your own sources. Point the system at the firm’s licensed materials and matter files so answers draw on what the firm already has.

Require citations. Configure the tool to cite primary authority for every claim, which makes verification fast and routine.

Keep queries in-house. Run retrieval and synthesis on a private stack so the question, often the heart of the matter, never leaves the firm.

Want research automated without privileged queries leaving your firm?

Contact us about Private Legal Research AI →
Not without verification. Independent testing by Stanford HAI found even leading tools return incorrect or unsupported statements, so a lawyer confirms every citation before relying on it. Running research on a private, self-hosted stack adds the missing piece by keeping the privileged query inside the firm.
Cited answers to research questions, case and statute summaries, first-draft research memos, cite-checking, and search across the firm's own files. Each output is a draft a lawyer verifies rather than a finished product.
All three process the query on the vendor's cloud. They differ in sources and features, but for privileged research the shared point is that the question leaves the firm, which is why some firms run the same workflow on a private stack.
Open models plus a search layer over the firm's licensed sources and matter files, running inside the firm's own tenant. It returns the same cited answers while the query and any work product stay in-house.
Cloud tools process the query, which can reveal strategy, on the vendor's infrastructure. For privileged matters, keeping retrieval and synthesis on a private stack meets the confidentiality duty ABA Opinion 512 places on lawyers.
Index the firm's licensed materials and matter files, require citations to primary authority on every claim, and run retrieval and synthesis on a private stack so queries stay in the firm.

The bottom line

AI legal research automates finding and synthesizing authority, and the choice that matters is where your privileged queries run. For confidentiality-bound firms, a private, self-hosted research stack delivers the speed while keeping queries in-house. A short scoping conversation will map your first research workflow.

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