AI Tools Index / Legal research / CoCounsel
Legal research · reviewed Sep 2026 · sample review

CoCounsel

Thomson Reuters

Research, summarisation and review anchored to a first-party citator — the most defensible answer in the category to the hallucinated-citation problem.

Our verdict

Tier B — the strongest evidential story of the general-purpose assistants, because verification is built into the architecture rather than promised in a policy. The trade is legacy usability and lock-in maths that the partnership, not the product team, has to accept.

What it does

Case law research, deposition and document summarisation, contract analysis and drafting grounded in primary sources.

Where it holds up

  • Citations resolve against first-party primary sources
  • Familiar procurement path for firms already on Westlaw
  • Summaries carry links a supervisor can actually check

Where it doesn't

  • Interface heritage shows; less pleasant than newer tools
  • Ecosystem lock-in is real and cumulative
  • Premium pricing layered on existing subscriptions

Data posture, as documented

What the vendor's own material and terms say — and where the answer was not published, we say so rather than guess.

locationEnterprise hosting with regional options
trainingNo customer-content training per published terms
retentionGoverned by the master agreement
subprocessorsDocumented; large vendor so diligence is straightforward

What it costs, realistically

Subscription, typically bundled with research platform renewals.

Who it suits

Good fit

Firms already inside the Thomson Reuters estate, and litigators who must verify.

Poor fit

Anyone shopping purely on interface or cost.

How we assessed it

Documentation and terms review; citation-verification spot checks planned.

Review history

DateChange
Sep 2026First entry.
Published under our method. Scores are editorial opinion at the review date, formed from vendor documentation, published terms and our own testing where stated. We take no payment from vendors and vendors do not see scores before publication. Nothing here is legal advice or a procurement recommendation for your firm's circumstances. Spotted an error? Tell us and we will correct or re-score it.