Three contract AI platforms, three different philosophies.

Three contract AI platforms, three different philosophies. Kira extracts and organizes. Luminance reviews and redlines. Spellbook drafts and suggests. They all touch contracts, but choosing between them is like choosing between a microscope, an X-ray machine, and a surgeon's tool — each does something the others can't.

This three-way comparison maps each tool to the specific contract workflow it dominates. Most firms don't need all three. But every firm doing contract work needs at least one.

Kira Systems: Extract and Organize at Scale

Kira's core capability is provision extraction. Feed it 10,000 contracts and it identifies, extracts, and organizes specific provisions across the entire set — change of control clauses, assignment restrictions, non-competes, indemnification terms. Kira recognizes 1,000+ built-in provision types and can be trained to find custom provisions unique to your practice.

Best for: M&A due diligence, portfolio analysis, lease abstraction, regulatory compliance reviews across large contract sets.

Not for: Drafting new contracts or reviewing individual agreements in real-time.

Key stats: 95%+ extraction accuracy for trained provisions. Handles PDF, Word, and scanned documents. Processes thousands of documents in hours. Acquired by Litera in 2021.

Pricing: Enterprise-only, typically $50,000-$100,000/year. Justified when your firm regularly processes large document sets (1,000+) for deals or compliance reviews.

Luminance: Review and Redline Autonomously

Luminance's core capability is intelligent contract review. Its AI reads contracts holistically — understanding context, intent, and risk — rather than just extracting specific provisions. Luminance's autopilot mode can review a 40-page contract and produce a marked-up version with identified risks, flagged deviations from standard positions, and suggested redlines in under 4 minutes.

Best for: Inbound contract review, redlining against your playbook, cross-border contracts (14+ languages), and high-volume contract processing where speed matters.

Not for: Net-new contract drafting from scratch or large-scale provision extraction across thousands of legacy documents.

Key stats: Sub-5-minute review time for standard contracts. 14+ language support without translation. Uses proprietary LLMs trained exclusively on legal documents.

Pricing: Enterprise-only, typically $2,000+/month per user. ROI is immediate for firms reviewing 20+ inbound contracts per month — the time savings on first-review alone cover the cost.

Spellbook: Draft and Suggest in Real-Time

Spellbook's core capability is contract drafting assistance. It sits inside Microsoft Word and provides real-time clause suggestions, generates first drafts based on deal parameters, and flags missing provisions as you draft. Spellbook learns from your firm's precedent library, so suggestions reflect your preferred language and style.

Best for: Drafting new contracts, building from templates, real-time clause suggestions while drafting, and transactional lawyers who live in Microsoft Word.

Not for: Reviewing large volumes of inbound contracts or extracting data from existing contract portfolios.

Key stats: Trained specifically on legal contracts, not general text. Integrates directly into Microsoft Word. Suggests clauses based on deal context and your firm's precedent.

Pricing: $500-$1,000/month per user. Accessible to mid-size firms, not just enterprise — the lowest price point of the three.

Head-to-Head: Which Tool Wins Each Use Case

Due diligence (reviewing data room documents): 1st: Kira — built for exactly this 2nd: Luminance — strong but less focused on extraction 3rd: Spellbook — not designed for bulk review

Daily contract review (inbound agreements): 1st: Luminance — autopilot review is unmatched 2nd: Spellbook — good for Word-based review 3rd: Kira — overkill for individual contracts

Contract drafting (new agreements): 1st: Spellbook — purpose-built for drafting 2nd: Luminance — has drafting features but review is the focus 3rd: Kira — doesn't draft

Portfolio analysis (reviewing existing contract sets): 1st: Kira — designed for large-scale extraction 2nd: Luminance — handles volumes but extracts less systematically 3rd: Spellbook — not designed for this

Cross-border contracts: 1st: Luminance — 14+ languages, no translation needed 2nd: Kira — some multi-language support 3rd: Spellbook — primarily English

The Decision Framework: Which One to Buy

Answer these three questions:

1. What's your primary contract workflow? - Mostly drafting new contracts → Spellbook - Mostly reviewing inbound contracts → Luminance - Mostly analyzing large document sets → Kira

2. What's your budget? - Under $1,000/month per user → Spellbook (only option at this price) - $2,000-$3,000/month per user → Luminance - Enterprise budget ($50K+/year) → Kira

3. Where do you work? - Microsoft Word → Spellbook (native integration) - Browser-based → Luminance (web platform) - Need to process uploaded documents at scale → Kira

Most firms need only one of these tools. The exception: Am Law 100 firms with both a transactional practice (Spellbook for drafting) and an M&A practice (Kira for due diligence). Adding Luminance on top of either makes sense only for firms doing heavy cross-border work or high-volume inbound contract review.

The Bottom Line: Spellbook for drafting, Luminance for review, Kira for extraction. They're three different tools for three different jobs. Most firms need exactly one — pick the one that matches how you primarily interact with contracts. And if you need a budget alternative to all three, Claude Pro at $20/month handles basic versions of all three tasks.