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Casetext CoCounsel (legacy)

Casetext (Thomson Reuters) · HQ US · founded 2013 · acquired · Last checked 2026-09-11

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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.

First GPT-4-powered legal assistant (March 2023); acquired by Thomson Reuters in August 2023 and merged into CoCounsel Legal and Westlaw. See the Westlaw / CoCounsel record for current facts.

Category
Legal research · case-law research, document review, brief analysis
Built for
Large firms, Mid-sized firms, Small firms & solos
Model providers (disclosed)
OpenAI, Google
Data residency options
US, UK, Australia, Canada
Pricing
Not published
Markets
US
Last checked
11 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.

No training on customer data
documented yessource
SOC 2
documented yessource
ISO 27001
not disclosedsource
ISO 42001
documented yessource
Zero retention with model providers
documented yessource
DPA offered
not disclosedsource
Private deployment
not disclosedsource

What the public documentation states

Casetext CoCounsel is a legacy record for the former Casetext service now under Thomson Reuters; casetext.com redirects to Thomson Reuters CoCounsel. Thomson Reuters' CoCounsel page names OpenAI and Google as third-party partners and says they are contractually prohibited from using customer data to train their models. It also says GenAI LLM provider calls use zero-retention APIs, customer inputs and outputs are not used to train or improve CoCounsel, and region-based hosting is available in the UK, Australia and Canada. Public pages state AES-256 encryption at rest, SOC 2 and ISO 42001 certification, and a privacy statement last updated 31 July 2026. Pricing pages did not publish a CoCounsel price. The vendor says CoCounsel surfaces sources and reasoning from verified information.

In the vendor's words

“third-party partners, such as OpenAI and Google”
Thomson Reuters CoCounsel page
“contractually prohibited from using any customer data to train their models”
Thomson Reuters CoCounsel page
“All interactions with GenAI LLM providers use zero-retention API calls”
Thomson Reuters CoCounsel page
“Region-based hosting is available in the UK, Australia, and Canada”
Thomson Reuters CoCounsel page

Not disclosed on public pages

"Not disclosed" records that no public statement was found where we looked, on the date shown. It does not assert that the control, term or figure is absent.

Not published on the pages we read on 2026-09-11: DPA, sub-processor list, terms update date, free trial, list price, minimum term, seat floor, ISO 27001, private deployment and SSO/SAML. A procurement or DPIA review normally asks for these points to confirm processor obligations, model-provider data flow, access controls, client confidentiality treatment and competence/supervision procedures for cited AI research.

Questions to put to the vendor

  1. Which Thomson Reuters entity contracts for legacy Casetext customers now using CoCounsel or Westlaw?
  2. Where is US-region data hosted if a customer does not select UK, Australia or Canada region-based hosting?
  3. Can Thomson Reuters provide a sub-processor list covering OpenAI, Google and any hosting providers?
  4. Does the zero-retention API statement apply to all CoCounsel skills and uploaded documents?
  5. What benchmark results support the verified-information method and source-reasoning statements?

Accuracy evidence

No published accuracy or hallucination evaluation found as of 2026-09-11.

Related incidents

No incidents are recorded for this tool as of 2026-09-11.

Ownership · Acquired by Thomson Reuters for $650M cash, closed 17 Aug 2023.

Sources

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Cite this record

SafeLegalAI Legal Tech Tools, "Casetext CoCounsel (legacy)", safelegalai.com/tools/casetext-cocounsel (last checked 2026-09-11, accessed 2026-10-07). Data: CC BY 4.0.

Documented facts, side by side

Facts from both vendors' pages in one table; never a ranking. All comparisons.

Also in Legal research

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