Harvey, CoCounsel, and Spellbook are the three credible legal AI agents in 2026 — and they target meaningfully different parts of the legal workflow. Treating them as direct competitors misses the point. Here's the honest comparison and how to pick.
The 30-second take
Harvey AI — General-purpose legal AI agent backed by OpenAI + Sequoia. Best for greenfield enterprise deployments where you want the most capable + most polished tool. Most expensive.
CoCounsel — Thomson Reuters' legal AI integrated into Westlaw. Best for firms already paying for Westlaw who want AI as an add-on rather than a new vendor. Materially cheaper for Westlaw shops.
Spellbook — Contract-drafting agent that lives inside Word. Best for transactional teams + in-house counsel + solo lawyers focused on contract work specifically. Cheapest entry point, narrowest scope.
Side-by-side
| Dimension | Harvey | CoCounsel | Spellbook |
|---|---|---|---|
| Primary scope | All legal work | Research + drafting | Contracts only |
| Primary surface | Web app | Westlaw integration | Word add-in |
| Backed by | OpenAI + Sequoia | Thomson Reuters | Spellbook standalone |
| Pricing transparency | Enterprise sales | Westlaw add-on | Public ($69-159/seat) |
| Target firm size | Am Law + mid-market | Existing Westlaw shops | Solo + small firms + in-house |
| Westlaw integration | Some | Native | Limited |
| Practical Law integration | No | Yes | No |
| Innovation pace | Fast | Slow | Medium |
| Procurement difficulty | High | Low (if Westlaw) | Very low |
When Harvey wins
Harvey is the right pick when:
- You're greenfielding your legal-AI stack (no existing Westlaw lock-in)
- You're an Am Law firm or large mid-market firm
- You need broad coverage (research + drafting + discovery + litigation)
- You value innovation pace + modern UX
- Procurement is willing to absorb a 4-6 week sales cycle
- Budget supports $50K-1M+/year
Harvey is the highest-capability + most-polished option. The price reflects it.
When CoCounsel wins
CoCounsel is the right pick when:
- Your firm is already a Westlaw subscriber (most US firms are)
- You want AI as an add-on, not a new vendor introduction
- Citation provenance + KeyCite accuracy matter to your practice
- Procurement comfort + lower-risk migration matter
- Budget is constrained vs Harvey's enterprise pricing
- Practical Law integration is useful for transactional work
The Westlaw integration depth + bundled pricing is the moat.
When Spellbook wins
Spellbook is the right pick when:
- Your work is mostly contracts (transactional, in-house, contract management)
- You + your team already work in Word
- You're solo, small firm, or budget-constrained
- You don't need broader legal AI scope (litigation, research, discovery)
- You want public pricing + fast onboarding
Spellbook intentionally went narrow to win the contract-drafting workflow. It's excellent at what it does.
The honest "run multiple" reality
Most Am Law firms with serious AI investment run all three:
- Harvey for litigation work, complex research, novel matters, deposition prep
- CoCounsel for Westlaw-anchored case law research where citation provenance matters
- Spellbook for transactional contract drafting + review (inside Word where the work already happens)
Combined cost for a 50-200 lawyer firm: roughly $300K-1.5M/year. The productivity gains across an 8-15× ROI range justify the spend at firm scale.
The honest "pick one" reality
Solo + small firm with mostly contract work: Spellbook alone. $69-159/seat/month. Done.
Solo + small firm with mixed practice: CoCounsel (if you're already on Westlaw) or Harvey (greenfield). Pick one — the second tool isn't justified at this scale.
Mid-market firm (10-50 lawyers): CoCounsel if you're a Westlaw shop, Harvey if you're greenfield. Add Spellbook if your contract volume justifies the marginal $69-159/seat/month.
Am Law 200 firm: Harvey as primary, CoCounsel if you're heavily invested in Westlaw, Spellbook for transactional teams. Run two or three — the cost is rounding error at this scale.
Bottom line
The "Harvey vs CoCounsel vs Spellbook" framing is misleading — they're not direct competitors. They target different scopes (all-legal vs research+drafting vs contracts-only), different firm scales (Am Law vs mid-market vs solo), and different procurement profiles (greenfield vs Westlaw-shop vs budget-constrained). Pick the one that matches your scope + scale + budget. Many firms end up running multiple.
Best AI for law firms → · Harvey review → · CoCounsel review → · Spellbook review →