CoCounsel by Thomson Reuters: What It Is and Whether It Fits Your Firm (2026)

Summary

CoCounsel reached 1 million users in February 2026. Thomson Reuters is targeting 10 million by year-end. The coverage of this milestone has been widespread — and largely unhelpful for a small law or accounting firm trying to figure out whether any of it applies to them.

Here is what it actually means for a 5–25 person firm: CoCounsel is not a new AI tool you can download and subscribe to. It is an AI research layer built into Thomson Reuters' existing platforms — Westlaw (legal research), Practical Law (drafting), and Checkpoint (tax research). If you already subscribe to one of these platforms, CoCounsel may be available to you today, bundled into your current plan. If you don't subscribe to TR, CoCounsel isn't accessible at small-firm pricing — and the 1 million user milestone is not a reason to change that.

This page covers what CoCounsel does, how it compares to Harvey and general AI tools, what it costs, and the two-question framework for whether your firm should use it.

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What CoCounsel Is (and What It Is Not)

CoCounsel is an AI research assistant built into Thomson Reuters' existing professional platforms. It is not a standalone tool you can subscribe to independently.

It lives inside three TR products:

• Westlaw — legal research, case law, statutes, secondary sources
• Practical Law — drafting templates and practice guides
• Checkpoint — tax research, IRS guidance, and regulatory analysis

If your firm already subscribes to any of these platforms, CoCounsel is part of your ecosystem today. If you don't subscribe to a TR product, CoCounsel is not accessible at small-firm pricing — there is no standalone entry point.

The 1 million user milestone Thomson Reuters announced in February 2026 reflects this model: existing TR customers getting AI features built into platforms they already pay for. It is not a new-product adoption story. It is an upgrade rollout to an established customer base.

What CoCounsel does not do:

• Draft client communications or marketing copy (ChatGPT or Claude are better tools for that)
• Function as a general AI assistant outside the TR platform
• Operate without an active Westlaw or Checkpoint subscription
• Replace attorney or accountant professional review — all outputs require judgment before use

Think of it this way: CoCounsel is to Westlaw what Copilot is to Microsoft 365. It augments a tool you already use — it doesn't transform your workflow from the outside.

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What CoCounsel Does in Westlaw

Within Westlaw, CoCounsel lets you ask legal research questions in plain English and receive cited answers grounded in TR's primary source database — real case law, statutes, and secondary sources, with direct source links.

Here is what the workflow looks like in practice: instead of building Boolean keyword queries and filtering by jurisdiction, you type "What is the standard for piercing the corporate veil in a Delaware LLC?" CoCounsel searches Westlaw's database and returns a structured response with relevant cases cited and linked. The initial retrieval work — which might normally take 45–60 minutes — can happen in minutes.

Where CoCounsel performs well:

• Finding relevant precedent on established legal questions
• Surfacing citations that might be missed in a keyword search
• Reducing the mechanical part of research for matters with clear precedent

Where it is less useful:

• Novel or unsettled legal questions where synthesis matters more than retrieval
• Practice areas with limited Westlaw database coverage
• Any task requiring original legal analysis or argument construction

On professional responsibility: ABA Formal Opinion 512 (2024) is unambiguous — attorney review of AI-assisted research is not optional. The supervising attorney remains responsible for all outputs used in client work. CoCounsel reduces research time. It does not reduce professional accountability.

For a more detailed breakdown of where CoCounsel performs and where it falls short in legal research, see our full review.

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What CoCounsel Does in Checkpoint (for Accounting Firms)

Thomson Reuters Checkpoint is the tax research platform used by accounting, advisory, and tax practices. CoCounsel on Checkpoint applies the same model as Westlaw: ask a tax question in plain English, receive a cited answer grounded in Checkpoint's source material — IRS code provisions, Treasury regulations, and TR's editorial analysis.

For accounting firms already paying for Checkpoint, this is a meaningful upgrade. Instead of manually navigating Checkpoint's database to find the right IRS publication, you ask the question and get a cited response linked to the source. The grounding in IRS primary sources makes CoCounsel substantially more reliable for tax research than using a general AI tool (ChatGPT, Claude) answering the same question from training data alone.

Checkpoint coverage notes:

• Federal tax — Strong. IRS guidance, Treasury regulations, and code provisions are Checkpoint's core. Coverage here is comprehensive and well-suited for AI-assisted retrieval.
• State tax — Variable. Checkpoint's state-level database completeness varies by jurisdiction. Firms doing heavy multi-state tax work should test CoCounsel against their most complex state research tasks before relying on it.

If your firm doesn't currently subscribe to Checkpoint, CoCounsel is not a reason to change that. A full Checkpoint subscription starts at several thousand dollars per year — that cost needs to be justified by research volume, not by AI features. The same two-question framework applies: research volume first, AI capability second.

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CoCounsel vs. Harvey AI vs. General AI Tools

The key question for a small firm owner: where does CoCounsel sit relative to the other AI tools in this space?

Tool	Best for	Price point	Small firm fit
CoCounsel (Westlaw)	Legal research, precedent analysis	Bundled with Westlaw (~$500–$1,500/mo)	Good — if already subscribed
CoCounsel (Checkpoint)	Tax research, IRS/regulatory analysis	Bundled with Checkpoint	Good — if already subscribed
Harvey AI	Complex legal drafting, enterprise legal work	Custom pricing; 20–50 seat minimum, typically $1,000+/mo	Built for BigLaw, not small firms
ChatGPT / Claude	Drafting, summarization, client communications	$20–25/user/month	High fit — requires professional supervision
Clio AI	Practice management, matter tracking, client comms	Bundled with Clio ($39–99/user/mo)	Best for non-research tasks
Perplexity for Work	Quick research with source citations	$40–60/month	Useful for secondary research

The pattern worth noting: the tools with the strongest research grounding (CoCounsel, Harvey) require either an existing enterprise subscription or enterprise pricing. The tools accessible to small firms on their own (ChatGPT, Claude, Perplexity) are not purpose-built for deep legal or tax research.

For a small firm not already subscribing to TR, the realistic starting path is: general AI tools at $20–25/month for drafting and analysis, Perplexity for quick cited research, and CoCounsel when a full Westlaw or Checkpoint subscription is justified on its own merits. That gap between "best research grounding" and "small firm accessible" is real, and it will not close in 2026.

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CoCounsel Pricing for Small Firms

Thomson Reuters does not publish CoCounsel pricing as a separate line item. Here is what is publicly known and widely reported as of 2026:

• CoCounsel is bundled into newer Westlaw subscription tiers. Westlaw Edge and recent Plus contracts typically include CoCounsel access. If you're on one of these tiers, you may already have access — check your agreement or call your TR rep.
• Westlaw for a small firm (1–5 attorneys, general practice) typically runs $500–$1,500/month, depending on firm size, practice area, and whether you're on a legacy contract.
• Checkpoint for accounting firms follows similar pricing — CoCounsel access is bundled into newer subscription tiers for existing customers.
• There is no standalone CoCounsel subscription at small-firm pricing. The product cannot be purchased independently without a full TR platform subscription.

The honest bottom line: if your firm doesn't currently subscribe to Westlaw or Checkpoint, the cost of entry is a full TR subscription — roughly $6,000–$18,000+ per year for a small firm depending on size and tier. That cost is justified by research volume, not by AI features. Don't buy a TR subscription because of CoCounsel.

If you're already a TR subscriber and haven't activated CoCounsel, call your rep today. There is a real chance it is already included in your current contract.

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Should Your Firm Use CoCounsel? (Two-Question Framework)

The decision is simpler than the coverage makes it look. Answer two questions:

Question 1: Does your firm currently subscribe to Westlaw or Checkpoint?

If yes — activate CoCounsel now. Log into your TR platform and look for the AI research interface in the research panel. Run it on three real tasks from the past month. If it saves 30–60 minutes per task, the ROI on your existing subscription just improved at no additional cost. There is no implementation risk — it is already in your platform.

If no — move to Question 2.

Question 2: Does your research volume justify a Westlaw or Checkpoint subscription on its own merits?

If yes — buy the subscription, activate CoCounsel, and use it. The AI features are a significant bonus on top of research infrastructure you needed anyway.

If no — don't let the 1 million user headline manufacture urgency for your firm. Start with ChatGPT or Claude at $20–25/month for drafting and general analysis. Add Perplexity for cited secondary research. Revisit the TR subscription question in 12 months when your research volume makes the economics clearer.

For accounting firms specifically: if you subscribe to Checkpoint, CoCounsel for tax research is a direct upgrade over using a general AI for the same task. The grounding in IRS primary sources meaningfully reduces the risk of a confidently wrong answer on a tax question. Test it against your most recent complex research question and compare to your usual method.

The firms that fall behind on AI aren't the ones who skipped CoCounsel. They're the ones who froze on all AI tools waiting for the perfect product. Start where you are. Add CoCounsel when the economics make sense — and not before.

For a full evaluation of CoCounsel including detailed workflow examples, coverage limitations, and the full competitive comparison, read the in-depth review.

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Frequently Asked Questions

What is CoCounsel by Thomson Reuters?

CoCounsel is an AI research assistant built directly into Thomson Reuters' professional platforms — Westlaw (legal research), Practical Law (drafting templates), and Checkpoint (tax research). It is not a standalone AI tool. You ask a natural language question — "What is the standard for piercing the corporate veil in Delaware?" — and CoCounsel searches TR's curated primary source database and returns a cited answer grounded in real case law, IRS code, or regulatory text. CoCounsel reached 1 million users in February 2026, with TR targeting 10 million by end of year.

How does CoCounsel compare to Harvey AI for small law firms?

CoCounsel and Harvey serve different market segments. CoCounsel is accessible to small firms through existing Westlaw or Checkpoint subscriptions (typically $500–$1,500/month for a small firm). Harvey AI is priced for Am Law 100 firms and large corporate legal departments — custom pricing that typically exceeds $1,000/month, with minimum seat requirements of 20–50. For a 5–15 attorney firm, CoCounsel is the realistic option if you already subscribe to Westlaw. Harvey is not priced for this market.

Is CoCounsel available to firms that don't subscribe to Westlaw or Checkpoint?

No. CoCounsel is not sold as a standalone product at small-firm price points. It requires an active Thomson Reuters subscription to Westlaw (for legal) or Checkpoint (for tax). If you already subscribe to either platform, CoCounsel may already be included — check your subscription tier. Westlaw Edge and newer Plus tiers typically include it. Firms not currently subscribing to TR products would need to purchase a full subscription to access CoCounsel, at $500–$1,500/month or more depending on firm size.

What does CoCounsel do in Westlaw?

Within Westlaw, CoCounsel lets you ask legal research questions in natural language and receive answers grounded in Westlaw's primary source database — real case citations, statutes, and secondary sources — rather than AI-generated text from general training data. For a matter with established precedent, CoCounsel replaces the first 45–60 minutes of traditional research: you get relevant authority surfaced and cited, with source links, without manually running multiple keyword queries. You still need an attorney to read, evaluate, and apply the results — the supervising attorney remains responsible under ABA Formal Opinion 512.

Can accounting firms use CoCounsel for tax research?

Yes. CoCounsel integrates with Thomson Reuters Checkpoint, the tax research platform used by accounting and advisory firms. Within Checkpoint, it provides AI-assisted tax research grounded in IRS guidance, Treasury regulations, code provisions, and TR's editorial analysis. For accounting firms already paying for Checkpoint, CoCounsel is a direct upgrade over using a general AI tool (ChatGPT, Claude) for the same task — the grounding in IRS source data significantly reduces the risk of a confidently wrong answer. If you don't currently subscribe to Checkpoint, the full subscription cost is not justified by CoCounsel alone.