CoCounsel
Agentic legal assistant (Thomson Reuters) for research, document review, and drafting, grounded in Westlaw and Practical Law. 1M+ users.
CoCounsel (Thomson Reuters, originally Casetext) is an agentic legal assistant grounded in Westlaw and Practical Law, with 1M+ users across 107 countries. Its next-generation 'CoCounsel Legal,' rebuilt on the Claude Agent SDK, handles conversational multi-step execution across research, document review, deposition prep, and contract analysis. Pricing runs roughly $225–500/user/month, often bundled with Westlaw.
Vendor details
Canonical URL
https://legal.thomsonreuters.com/en/products/cocounsel-legal
Category
Enterprise operations agent
Subcategory
Legal — research/drafting agent (Westlaw-grounded)
Use cases & customers
Primary use cases
Target customers
Deployment options
In practice
Your research is only as trustworthy as its sources. CoCounsel is grounded in Westlaw and Practical Law, so its answers rest on authoritative legal content rather than the open web.
A matter needs research, then document review, then deposition prep, and switching tools each time kills momentum. CoCounsel Legal handles the multi-step work conversationally in one flow.
You want to brief the assistant like a junior associate, not write a query. CoCounsel Legal, rebuilt on the Claude Agent SDK, takes a plain-language ask and executes across research and contract analysis.
Agentic Index coverage score
7.0 / 14 capabilities · 50%
| Integrations & Tool CallingCoCounsel Legal works across Westlaw, Practical Law, Microsoft 365, and document management systems within a single unified experience, retrieving from both Thomson Reuters content and the customer's own systems, Thomson Reuters CoCounsel Legal product page 2026-06-09 | Full |
|---|---|
| Workflow OrchestrationDeep Research plans multi step research, builds, executes, and iteratively improves a research plan, and the next generation experience takes a matter described in plain language, creates a plan, reasons through the legal issues, retrieves from precedents and Westlaw, then drafts with citations, Thomson Reuters CoCounsel Legal launch 2025-08-05 and June 2026 releases 2026-07-22 | Full |
| Knowledge Grounding & RAGDeep Research is grounded in Westlaw and Practical Law authoritative content combined with the firm's own precedents, with International Legal Research extending grounding across jurisdictions, and Thomson Reuters positions the content estate as the reason its agentic AI is reliable, Thomson Reuters CoCounsel Legal launch 2025-08-05 and June 2026 releases 2026-07-22 | Full |
| Human Oversight & GuardrailsDeep Research Verify is designed to move lawyers from AI generated insight to well grounded legal judgment by surfacing what to check, but the workflow is verification after output rather than an approval gate before action, and bounded autonomy controls were not documented, Thomson Reuters CoCounsel Legal June 2026 releases 2026-07-22 | Partial |
| Security, Identity & GovernanceNo security attestations, identity controls, or agent permission model was retrieved in this pass, Thomson Reuters CoCounsel product pages 2026-07-22 | Unable to verify |
| Observability & AuditabilityDeep Research Verify automatically checks whether cited authority supports the assertions made, validates cited Westlaw and Practical Law sources, highlights relevant supporting passages, and flags potential misattributions or mischaracterisations, giving traceable authority behind every claim, Thomson Reuters CoCounsel Legal June 2026 releases 2026-07-22 | Full |
| Memory & State PersistenceThe next generation experience retrieves from the customer's own precedent library so firm knowledge persists across matters, but agent session memory or cross task state was not documented, Thomson Reuters CoCounsel Legal June 2026 releases 2026-07-22 | Partial |
| Deployment & Data ResidencyCoCounsel Legal runs as jurisdiction specific offerings across the US and UK with Deep Research variants on local content sets and international research added in 2026, but customer selectable regions or residency guarantees were not documented, Thomson Reuters UK expansion 2026-01-26 | Partial |
| Prebuilt Agents, Templates & PacksCoCounsel Legal ships agentic guided workflows and expert created prompts out of the box alongside Deep Research, Tabular Analysis for document review, and a clause library, built by thousands of Thomson Reuters domain experts, Thomson Reuters CoCounsel Legal launch 2025-08-05 and UK expansion 2026-01-26 | Full |
| Triggers & Channel CoverageAgentic workflows are reachable inside Westlaw, Practical Law, Microsoft 365, the CoCounsel app, and document management systems, but event or schedule based trigger configuration was not documented, Thomson Reuters CoCounsel Legal product page 2026-06-09 | Partial |
| Model Flexibility & RoutingThomson Reuters cites advanced reasoning models behind the product but exposes no customer facing model choice or routing, Thomson Reuters CoCounsel product pages 2026-07-22 | Unable to verify |
| APIs, SDKs & MCP ExtensibilityNo API, SDK, MCP surface, or customer agent builder was retrieved in this pass, Thomson Reuters CoCounsel product pages 2026-07-22 | Unable to verify |
| Testing, Debugging & OptimizationDeep Research iteratively improves its plan at runtime, but agent testing, simulation, or versioning tooling was not documented, Thomson Reuters CoCounsel product pages 2026-07-22 | Unable to verify |
| Browser & Computer UseNo browser or computer use capability was documented, Thomson Reuters CoCounsel product pages 2026-07-22 | Unable to verify |
The Agentic Index coverage score grades every vendor Full, Partial or Unable to verify against the same 14 buyer facing capabilities, from public evidence only. Each capability links to how all vendors in the index score on it. How this evidence is graded
Recent platform changes
Thomson Reuters announced the general availability of the next generation of CoCounsel Legal. The updated platform introduces advanced agentic AI workflows and Deep Research capabilities, allowing the assistant to autonomously plan, select tools, and retrieve authoritative content from sources like Westlaw and Practical Law to execute complex, multi-step legal tasks.
Bears on: Agent capability
View sourceThomson Reuters introduced its proprietary large language model, Thomson, designed specifically for legal, tax, and compliance use cases. The model is integrated into CoCounsel Legal to power features like Tabular Analysis and is benchmarked to perform competitively with leading frontier models like Claude Opus 4.8.
Bears on: Agent capability
View sourceThomson Reuters rebuilt CoCounsel Legal on agentic infrastructure, moving it off discrete prompt-driven tasks. Users describe a legal matter in plain language and the agent plans the workflow, pulls authoritative content from Practical Law and Westlaw, and runs multi-step research and drafting in one continuous conversation.
Bears on: Agent capability
View sourcePricing
From $225/user/mo
seats
Included quota
CoCounsel Essentials (entry, ~$104+/user/mo): agentic AI for document review, drafting, summaries, timelines, comparisons, and contract work — but no Westlaw case-law research.
What is public
Thomson Reuters sells CoCounsel via an online configurator (no fixed list) for firms up to 10 attorneys; 10+ attorneys are quoted by sales. Four tiers: CoCounsel Essentials (AI-only, lowest), Westlaw Advantage + Essentials, Practical Law + Essentials, and CoCounsel Legal (full stack). Configurator anchor: Westlaw Advantage + Essentials for a solo with All-States & Federal is ~$639/user/mo (1-yr), ~$519/mo effective on a 3-yr term.
Billing mechanics
Per-seat subscription priced by tier, jurisdiction scope (circuits selected; 'All States & Federal' is most expensive), and contract term (12% off 2-yr, 18% off 3-yr). The AI (Essentials) is the floor; primary-law case research requires the Westlaw Advantage bundle; Practical Law guidance is a separate bundle, and getting both means the top CoCounsel Legal tier. Online pricing is for new customers only.
Cost watchouts
Case-law research requires the pricier Westlaw bundle, jurisdiction scope inflates price ('All States & Federal' is top), multi-year term lock-in for the best rate, Practical Law is a separate bundle, 10+ attorneys lose self-serve pricing
Variable cost rationale
Flat per-seat subscription with no usage metering; cost variance comes from configuration (jurisdiction/term/bundle), not consumption — so low ongoing variable exposure
Additional watchouts
Real cost is driven by the Westlaw bundle and jurisdiction scope, not the AI tier; deep Thomson Reuters ecosystem lock-in
Overage / add-ons
No usage metering disclosed; cost scales by tier, jurisdiction scope, seat count, and content bundles — not by consumption.
Sales call required
Mixed (some tiers require a call)
Lowest paid plan
~$225-500/user/mo (CoCounsel + Westlaw bundle ~$3K/seat/yr)
Commercial notes
12% off 2-yr, 18% off 3-yr terms; some firms get CoCounsel bundled into Westlaw renewals at little/no extra cost; CoCounsel Legal (Deep Research, agentic) launched Aug 2025; built on OpenAI models + Westlaw/Practical Law content
Key ambiguities
No fixed price list — the per-seat figure depends on configurator inputs (tier, jurisdiction, term); the AI-only Essentials floor price isn't prominently published
Cancellation / refund
1-, 2-, or 3-year terms (longer = bigger discount; the lowest effective rate needs a 3-yr commitment); new features included mid-term without re-buying; refund/exit terms deal-specific
Support SLA / resale
Standard support across tiers (chat/phone weekdays); enterprise/large-firm support via sales; integrations with Microsoft 365, DMS, and HighQ
Missing data
Thomson Reuters publishes no fixed price sheet; figures come from its online configurator and analyst reports. Exact per-seat price depends on tier, jurisdiction, and term; 10+ attorney pricing is sales-quoted only
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Alternatives to CoCounsel
The closest documented capability profiles to CoCounsel among enterprise operations agents tracked by Agentic Index, ordered by similarity on the same 14 point evidence the rankings use. No vendor pays for placement.
- Firmbase6.5 / 14Adds documented Testing, Debugging & Optimization
- Smart Bricks5.5 / 14A lighter documented profile than CoCounsel
- Arkestro8.0 / 14Adds documented Security, Identity & Governance and APIs, SDKs & MCP Extensibility, among others
- Balerion AI7.0 / 14Adds documented Security, Identity & Governance
- Cambio7.0 / 14Adds documented Security, Identity & Governance
- Clio6.0 / 14Fuller documented coverage on Human Oversight & GuardrailsCoCounsel vs Clio →
Similarity is computed from each vendor's Agentic Index coverage score evidence, axis by axis, not from the totals. How this evidence is graded