Legal AI
Compare Legal AI Tools
Most "legal AI" comparisons mislead because they treat tools that do different jobs as interchangeable. They are not. Two questions decide your shortlist before any feature comparison: which research platform you already pay for, and whether your need is research or drafting. No rankings, no scores, no checkmark grids.
Start here
Two questions decide your shortlist, before any feature comparison
1 · Which research platform do you already pay for?
Research AI activates on top of an existing subscription. It is not a standalone purchase. On Westlaw → evaluate CoCounsel. On LexisNexis → evaluate Lexis+ AI. On neither → this is a publisher-relationship decision first, an AI tool second.
2 · Is your need research, or drafting?
Research tools work at the knowledge layer (grounded in a legal database). Drafting tools work at the document layer. They are not substitutes. The most common evaluation mistake is comparing one against the other.
Three roles: not one shortlist
- Research AI Publisher-dependent. CoCounsel (Westlaw), Lexis+ AI (Lexis). Mid-size & large firms.
- Enterprise AI work platform Standalone, deployment-heavy. Harvey. Large firms with legal-ops resources.
- Adjacent: contract drafting A different job (document layer). Spellbook, inside Word. Evaluate independently.
This page does not pick a winner. It narrows the field to the role that fits your job. PI firms: AI demand-letter tools (EvenUp, Supio) are a separate decision that sits on top of your case-management system. See the PI Operations Matrix. For narrative depth on the research and enterprise tools, see the in-depth guide.
| Platform | Requires | Firm size | Adoption | Where it fits | Skip if |
|---|---|---|---|---|---|
| Thomson Reuters CoCounsel Research + Drafting AI research and drafting assistant built on the Westlaw platform No commercial relationship | Active Westlaw subscription | Mid-sizeLarge | Medium Attorney adoption and workflow-change management required; onboarding support available | Mid-size or large firm with an active Westlaw subscription where legal research, contract review, or deposition prep is a real throughput constraint. Strongest when it extends a workflow the firm already runs on Westlaw, not evaluated as a standalone AI purchase. | Firms without a Westlaw subscription. Solo or small firms whose primary bottleneck is intake or billing, not research velocity. Firms evaluating CoCounsel in isolation from their Thomson Reuters relationship. |
| Lexis+ AI Research AI-augmented legal research on top of the LexisNexis platform No commercial relationship | Active LexisNexis subscription | Mid-sizeLarge | Low Activates on an existing subscription or installs as an app; minimal onboarding | Firm with an existing LexisNexis subscription evaluating AI-assisted research, particularly where LexisNexis secondary sources are relied on. For most firms comparing CoCounsel and Lexis+ AI, the decision is primarily a Thomson Reuters vs. LexisNexis publisher relationship question. | Firms without an existing Lexis subscription. Solo or small firms not doing research-intensive work. Firms mid-evaluation between Westlaw and Lexis as base platforms. Settle the research platform decision first. |
| Harvey Drafting & Analysis Standalone enterprise AI for high-volume drafting, contract analysis, and due diligence No commercial relationship | None (standalone AI platform) | Large | High Enterprise deployment; legal ops or technology staff required for implementation | Large law firm or enterprise in-house team with high-volume drafting, contract analysis, or due diligence workflows and dedicated legal operations resources. Technology-forward firms with a clear document throughput problem that CoCounsel or Lexis+ AI does not address. | Solo, small, and most mid-size firms: Harvey's pricing, deployment model, and implementation complexity reflect its large-firm positioning. Firms whose primary operational problem is PM, intake, or billing. Firms evaluating Harvey because of AI visibility rather than a specific workflow problem. |
| Spellbook Adjacent: contract work Contract Drafting AI contract review and drafting inside Microsoft Word No commercial relationship | Microsoft Word (Word add-in only) | SoloSmallMid-sizeLarge | Low Activates on an existing subscription or installs as an app; minimal onboarding | Transactional lawyer or contract-heavy practice reviewing or drafting multiple contracts per week who wants AI assistance at the point of editing (inside Word, without switching tools). Accessible at all firm sizes. Relevant to evaluate independently of the research tools above. | Firms primarily needing legal research databases or litigation support. Practices not using Microsoft Word as their drafting environment. Not a substitute for CoCounsel or Lexis+ AI for research workflows. |
How to read this matrix
Start with the Primary Job column. It is the most important filter before comparing anything else. CoCounsel and Lexis+ AI are research AI: they extend a legal research database relationship your firm already has. Harvey is an enterprise AI work platform: standalone, deployment-heavy, and sized for large firms with dedicated legal operations resources. These are not interchangeable options.
The Requires column surfaces the single most common evaluation mistake for research AI: firms evaluating CoCounsel or Lexis+ AI as standalone AI products rather than as extensions of existing Westlaw or LexisNexis relationships. If your firm does not have the relevant publisher subscription, the evaluation question is materially different.
Spellbook is included as a context row because it appears in the same buyer conversation as AI, but its primary job, contract review and drafting inside Word, is categorically different from legal research or enterprise AI work. Evaluate it independently, not as an alternative to the research tools above.
The platform selector applies these dimensions interactively for a narrowed fit assessment.
In-depth comparison
In-depth Guide
CoCounsel vs. Lexis+ AI vs. Harvey →Narrative analysis of what each tool actually is, where each fits, publisher prerequisites, and five common evaluation mistakes. The matrix above is a fast-scan surface; this guide goes deeper.
Not Sure Which AI Tool Fits Your Firm?
The free Intake Audit takes 5 minutes. We assess your firm's size, practice area, and current workflows and deliver a written platform recommendation within 48 business hours.
Takes 5 minutes. No commitment.
30 minutes. No sales pitch.