Westlaw Precision / CoCounsel Legal
Thomson Reuters · HQ CA · Last checked 2026-09-03
Last checked = the date we last re-opened the vendor's published pages. Facts are what the vendor documents, not what it claims in marketing.
Thomson Reuters' generative-AI research and drafting assistant grounded in Westlaw and Practical Law; product family spans CoCounsel Legal, Drafting and Tax on a multi-model architecture.
- Category
- Legal research · case-law research, drafting in Word, document review, agentic assistant, Practical Law
- Built for
- Large firms, Mid-sized firms, Small firms & solos, In-house legal
- Model providers (disclosed)
- OpenAI, Google, Anthropic, own
- Data residency options
- Not disclosed
- Pricing
- enterprise
- Markets
- US
- Last checked
- 03 Sept 2026
What the vendor documents
Recorded from the vendor's own trust, privacy and terms pages. "Not disclosed" means we found no public statement, not that the control is absent.
Accuracy evidence
- third-partyStanford RegLab 'Hallucination-Free?' study, May 2024 Westlaw AI-Assisted Research hallucinated on ~33% of queries and was accurate on 42%; Ask Practical Law AI also tested.
- third-partyVals AI Legal AI Report (VLAIR), Feb 2025 CoCounsel 2.0 top in Summarization (77.2%), Document Q&A 89.6%, Data Extraction 73.2%, Chronology 78.0%.
- vendorThomson Reuters guardrails blog (vendor) Vendor cites 1,500+ nightly tests per skill and attorney review; declined the Oct 2025 Vals research bench.
Related incidents
Ownership · Thomson Reuters (NYSE/TSX: TRI); acquired Casetext for $650M in Aug 2023 and Safe Sign Technologies in 2024.
Sources
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Cite this record
SafeLegalAI Legal Tech Tools, "Westlaw Precision / CoCounsel Legal", safelegalai.com/tools/westlaw-cocounsel (last checked 2026-09-03, accessed 2026-09-04). Data: CC BY 4.0.
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