Harvey vs CoCounsel vs Spellbook: Legal AI Compared

Harvey, Casetext CoCounsel, and Spellbook are the three most-discussed AI tools in legal practice in 2026. They overlap in some areas, differ sharply in others. For firms picking, the right choice depends on practice mix, scale, and operational maturity.

The short answer

• Harvey for AmLaw 100 and large firms with budget for enterprise AI and custom workflow needs
• Casetext CoCounsel for solo through mid-size firms wanting accessible broad legal AI
• Spellbook for transactional practices at any size, especially those on Microsoft Word

Many firms use multiple tools. The question is which combination, not just "which one."

Use case by tool

Harvey:

• General legal AI platform
• Drafting briefs, motions, memos
• Document review at scale
• Legal research and analysis
• Custom firm-specific workflows
• Multi-document analysis across thousands of files

Casetext CoCounsel:

• Legal research with case-law synthesis
• Drafting briefs, memos, and contracts
• Document review for facts
• Deposition transcript analysis
• General legal assistant

Spellbook:

• Contract drafting inside Microsoft Word
• Contract review against playbooks
• Redline suggestions for negotiation
• Clause library access
• Word-native workflow

Pricing comparison (2026)

Harvey: Enterprise-only, quoted per firm.

Casetext CoCounsel: Per-attorney pricing, with volume discounts for larger firms and custom enterprise terms.

Spellbook: Solo, team and enterprise tiers, priced per attorney.

None of the three publishes one price that fits every firm, and pricing varies significantly with contract terms and bundles. Get written quotes for your headcount before comparing.

Output quality on common tasks

Brief drafting:

• Harvey: Best (legal-specific, enterprise-grade)
• CoCounsel: Good (legal-specific, accessible)
• Spellbook: Limited (not primary use case)

Contract drafting:

• Spellbook: Best (purpose-built for contracts)
• Harvey: Good (broader platform)
• CoCounsel: Adequate (general purpose)

Legal research:

• Harvey: Good (broader)
• CoCounsel: Best (research-specific strengths, Westlaw integration)
• Spellbook: Not designed for research

Multi-document analysis at scale:

• Harvey: Best (handles thousands of documents)
• CoCounsel: Good (smaller scale)
• Spellbook: Not designed for this

Implementation timeline

Harvey: 9-15 months from decision to full deployment. Enterprise sales cycle is significant.

CoCounsel: 30-60 days to full deployment. Faster onboarding, less custom integration.

Spellbook: 30-60 days to full deployment. Word plugin install is quick, playbook training takes more time.

For firms needing fast time-to-value, CoCounsel or Spellbook beat Harvey on speed alone.

Customization depth

Harvey: Most customizable — firm-specific workflows, custom training on firm precedent, custom integrations.

CoCounsel: Moderate customization — firm-specific playbooks possible, less custom workflow flexibility than Harvey.

Spellbook: Strong customization for contracts specifically — firm playbooks, clause libraries, but contract-specific only.

When to choose each

Harvey if:

• Firm has 50+ attorneys (typically AmLaw 200 or larger)
• Practice mix includes meaningful litigation and transactional
• Budget supports enterprise AI deployment
• Operations team can support implementation
• Custom workflow needs are significant

CoCounsel if:

• Solo through mid-size firm
• Want accessible broad legal AI
• Mix of research, drafting, and document review needs
• Already on Westlaw or want Westlaw-integrated AI
• Don't need maximum customization

Spellbook if:

• Transactional practice (corporate, M&A, commercial)
• Firm is on Microsoft Word as primary document platform
• Want fast adoption without major workflow change
• Budget-conscious AI deployment
• Already have research tool, need contract-specific AI

When to use combinations

Spellbook + CoCounsel: Transactional firm wanting contract-specific AI plus broader legal AI for research and litigation work. Common at mid-size firms.

Harvey + Spellbook: Larger firm with enterprise general legal AI plus specialized contract tooling. Common at AmLaw 100.

All three: Larger firms doing everything. Cost is significant but the workflow specialization compounds.

Compliance posture

All three:

• SOC 2 Type II
• Encryption at rest and in transit
• Configurable retention
• Audit logs
• Data not used for training (enterprise tiers)

All three are appropriate for attorney use with client documents on enterprise tiers. Verify configuration matches firm policy.

Where each tool tends to fit

Harvey tends to fit larger firms with the volume and the budget to configure it, and the gains show up first in drafting, research and document review.

CoCounsel tends to fit small and mid-size firms that want research, memo drafting and deposition prep without an enterprise deployment.

Spellbook tends to fit transactional practices, where contract drafting, review and negotiation prep are the volume.

Measure each on your own matters before committing firm-wide.

What we'd watch for

Each platform is iterating quickly. Watch:

• Harvey: Pricing accessibility for mid-market, integration depth with practice management
• CoCounsel: Continued integration with broader Thomson Reuters stack
• Spellbook: Expansion beyond Microsoft Word, expansion into litigation tools

The competitive landscape will shift over 2026-2028. The choices that work today may need revisiting in 18-24 months.

Bottom line

Harvey, CoCounsel, and Spellbook each win in their lane. Most firms benefit from picking the right one for their primary practice mix and supplementing with general AI (ChatGPT Enterprise or Claude Team) for non-legal work.

Harvey is the premium pick for AmLaw scale. CoCounsel is the accessible pick for most firms below that. Spellbook is the specialized pick for transactional practices regardless of size.

The wrong move is paralysis. Pick one, deploy structurally, train staff, supervise output, and the productivity gains start immediately. The right combination can be refined over 6-12 months as the firm learns what works.