CoCounsel vs Westlaw AI: Which Thomson Reuters AI Tool?

CoCounsel and Westlaw AI are both Thomson Reuters products, which makes this comparison confusing for buyers. The short version: Westlaw AI enhances your research inside the Westlaw interface. CoCounsel is a standalone AI assistant that handles research plus document review, contract analysis, deposition prep, and timeline creation.

Think of it this way: Westlaw AI is a smarter search engine for case law. CoCounsel is a legal assistant that can do research AND other tasks. If you only need better research, Westlaw AI is sufficient. If you need AI across multiple legal workflows, CoCounsel is the broader tool.

Feature Comparison

CoCounsel offers legal research with Westlaw citations, document review, contract analysis, deposition preparation, and timeline creation from documents. It was built from Casetext (acquired for $650M) and operates as a multi-task legal AI platform.

Westlaw AI-Assisted Research focuses specifically on AI-powered legal research, natural language queries with Westlaw citations, brief analysis, document comparison, and research trail audit logging. It is an AI enhancement layer on top of the existing Westlaw research interface.

CoCounsel does everything Westlaw AI does for research, plus additional tasks. Westlaw AI does research within the familiar Westlaw interface. The research quality is comparable — both pull from the same Westlaw database.

Pricing and Cost

CoCounsel is estimated at $100-200/seat/month on top of existing Westlaw fees, or available as a standalone subscription with seat-based annual contracts.

Westlaw AI is included in Westlaw Precision subscriptions or available as an add-on for legacy Westlaw plans. It is not sold separately from Westlaw.

If you are already on Westlaw Precision, you may already have Westlaw AI included. CoCounsel is the premium upsell that adds multi-task capability. Thomson Reuters' pricing strategy is to bundle — contact your rep to understand what your current contract includes before purchasing additional features.

Data Privacy and Compliance

Both tools operate under Thomson Reuters enterprise data agreements. Neither trains on user queries. Both process data through Thomson Reuters infrastructure.

The data handling is essentially identical because both come from the same company. The only difference is scope — CoCounsel processes more types of documents (contracts, deposition transcripts, timelines) while Westlaw AI primarily handles research queries.

If you trust Thomson Reuters with one, you can trust them with both.

Best For

Choose Westlaw AI if your primary need is better, faster legal research within the Westlaw interface you already know. It is the right choice for firms that want AI enhancement without learning a new platform or adding significant cost.

Choose CoCounsel if you need AI assistance beyond research — document review, contract analysis, deposition preparation, timeline creation. It is the right choice for firms ready to invest in a multi-task legal AI platform.

Key insight: If you are already on Westlaw Precision, check whether Westlaw AI features are already in your contract. Many firms are paying for AI features they have not activated.

The Verdict

For most Westlaw subscribers, start with Westlaw AI — it may already be included in your plan, and it delivers the highest-value capability (citation-verified research) with zero learning curve. Upgrade to CoCounsel only when you have specific needs for document review, deposition prep, or contract analysis that justify the additional seat-based cost. Thomson Reuters wants you to buy both. Make sure you actually need both before signing.

The Bottom Line: Westlaw AI is research-only and may already be in your contract; CoCounsel adds multi-task AI at a premium — check your existing plan before buying.