**CoCounsel wins for litigation-heavy firms

CoCounsel wins for litigation-heavy firms. Spellbook wins for contract-focused practices. That's the split, and it's clean.

CoCounsel (Thomson Reuters) plugs directly into Westlaw's case law database and runs multi-agent workflows across research, drafting, and review. Spellbook lives inside Microsoft Word and focuses entirely on contract drafting, clause suggestions, and redlining. If you're comparing them head-to-head, you're probably asking the wrong question — they solve different problems. But if budget forces you to pick one, here's exactly how to decide.

What CoCounsel Actually Does in 2026

CoCounsel is Thomson Reuters' AI assistant built on GPT-4-class models with direct access to Westlaw's legal database. It handles research memos, document review, deposition preparation, contract analysis, and timeline generation — all within a single interface.

The multi-agent architecture means it breaks complex tasks into sub-tasks automatically. Ask it to analyze a contract and it'll flag risks, compare to market terms, and draft a summary memo without you managing each step.

The Westlaw integration is the real differentiator. CoCounsel citations come from verified case law, not hallucinated references. For litigation teams, that's table stakes. For transactional teams, it's nice-to-have.

Best for: Am Law 200 firms, litigation departments, teams already paying for Westlaw.

What Spellbook Actually Does in 2026

Spellbook is a Microsoft Word add-in trained on legal contracts. It suggests clauses, flags unusual terms, generates redlines, and helps you draft contracts faster without leaving your document.

The UX is the selling point. You're not switching between tabs or platforms — Spellbook surfaces suggestions inline as you draft. It's trained on millions of legal agreements, so the clause suggestions are genuinely useful, not generic AI filler.

Spellbook added review mode in late 2025, which lets you upload a counterparty's draft and get a risk analysis with suggested edits. It's not as deep as CoCounsel's contract analysis, but it's faster and cheaper.

Best for: Solo practitioners, boutique firms, contract-heavy practices, in-house legal teams.

Head-to-Head: Research, Drafting, Review

Legal Research: CoCounsel dominates. Spellbook doesn't do legal research at all — it's not designed for it. CoCounsel generates research memos with Westlaw-backed citations in minutes.

Contract Drafting: Spellbook wins. It's purpose-built for Word-based contract work. CoCounsel can draft contracts, but the workflow is clunkier because you're working in a separate interface.

Document Review: CoCounsel handles large-scale review (hundreds of documents). Spellbook reviews individual contracts. Different scale, different use case.

Brief Writing: CoCounsel only. Spellbook doesn't touch litigation documents.

Speed to Value: Spellbook. Install the Word add-in, start drafting. CoCounsel requires onboarding, training, and Westlaw integration setup.

Pricing Reality Check

CoCounsel is bundled with Westlaw Edge subscriptions at the enterprise level. Expect $150-300/user/month on top of your existing Westlaw spend. Thomson Reuters doesn't publish exact pricing — it's negotiated per firm. If you're not already on Westlaw, the total cost jumps significantly.

Spellbook runs $99-199/user/month depending on tier. The Starter plan covers basic drafting assistance. The Pro plan adds review mode, clause libraries, and priority support. No prerequisite subscriptions.

For a 10-attorney firm: - CoCounsel: ~$2,000-3,000/month (plus Westlaw) - Spellbook: ~$1,000-2,000/month (standalone)

Spellbook is roughly 40-60% cheaper for the same headcount, but you're getting a narrower tool.

Which One Should Your Firm Pick

Pick CoCounsel if: You're already on Westlaw, your practice is litigation-heavy, you need multi-document review, and your firm has 20+ attorneys. The ROI comes from replacing paralegal research hours and speeding up discovery.

Pick Spellbook if: You're a contract-focused practice, you work primarily in Word, you want fast ROI without enterprise onboarding, and you're budget-conscious. Solo and small firm attorneys get the most value here.

Pick both if: You're a mid-to-large firm with both litigation and transactional departments. They don't overlap much. CoCounsel for the litigators, Spellbook for the transactional team.

Pick neither if: You're a solo practitioner who can get 80% of the value from Claude or ChatGPT at $20/month. Seriously — for basic drafting and research, general-purpose AI tools are remarkably capable.

The Bottom Line: CoCounsel is the enterprise litigation workhorse; Spellbook is the contract drafter's best friend — most firms with mixed practices should run both.