Spellbook vs. Definely: Which Contract AI Platform Fits Your Workflow?

Spellbook and Definely are both legal AI products built around Microsoft Word, and both help lawyers review contracts. Definely works on the structure of the agreement. Spellbook works on the review position the lawyer takes on it.

Definely emphasizes defined terms, cross-references, proofreading, and the downstream effects of an edit.

Spellbook emphasizes review against Playbooks, redlines in Word, drafting from precedent, and how a term compares with outside market data.

Both products assist with review, work from internal precedent, and run inside Word, so the difference is in what each one is built to do there. This comparison covers what each product does and the pros and cons of each. It then sets out where Spellbook and Definely differ, what each costs to evaluate, and which team each one suits.

Key takeaways

• Pick Definely when the document is the problem: long agreements, dense defined terms and cross-references, and edits with consequences elsewhere in the file.

• Pick Spellbook when the position is the problem: first-pass review, redlining, consistent standards across reviewers, and evidence for a negotiation.

• Word integration does not separate them. Both suites are built around Word, so it is not a point of difference.

• Of these two products, only Spellbook publishes an external market dataset. Definely answers a market-standard claim from the organization's own precedent.

• Neither vendor publishes a per-seat price. Spellbook offers a seven-day free trial; Definely routes evaluation through a demo booking.

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What is Definely?

Definely is the Definely Review Suite, five legal products designed around complex contracts and Microsoft Word. All five run as Microsoft Word add-ins.

The original flagship product, Definely Draft, was renamed Definely Read in 2026 to better reflect how customers were already using it. The rename announcement was explicit that nothing about the setup changed: the same Word add-in, the same features, in the same place. Definely Draft is no longer a current product name, and the product it refers to was a reading and navigation add-in rather than a drafting tool.

What are the five Definely products?

• Defined-term and cross-reference navigation: Definely Read turns definitions and internal references into links the lawyer can open in place, and reports on defined, undefined, and unused terms.

• Legal proofreading: Definely Proof checks a document for placeholders, formatting inconsistencies, capitalization problems, and similar defects.

• Change-impact analysis: Definely Cascade traces the knock-on effects of a contractual change across related clauses, definitions, and references.

• Natural-language contract interrogation: Definely Enhance lets lawyers ask questions about a complex agreement, with answers tied back to specific provisions.

• Internal precedent retrieval: Definely Vault searches and inserts precedent clauses and definitions from connected repositories and document management systems.

Who is Definely built for?

The common theme is document understanding and control. On the published Definely Vault page, the search scope is the organization's own document repository and clause library, which is the shape of the whole suite: it works on the agreement in front of the lawyer and on the firm's own paper. Definely is therefore most relevant where the agreement itself is structurally dense and a small change can have consequences elsewhere in the document.

Pros

• Read addresses the tracing of definitions and cross-references, which is where review time goes on a long agreement.
• Cascade surfaces the related clauses, definitions, and references that a single edit may touch, which is a distinct job from flagging the edit itself.
• Proof is a dedicated proofreading pass rather than a side effect of review, covering placeholders, formatting inconsistencies, and defined-term usage.
• Vault retrieves precedent from iManage, NetDocuments, and SharePoint from inside Word, so the firm's own language stays reachable during drafting.

Cons

• The published product materials describe internal precedent and document analysis, not an external market dataset, so a counterparty's claim that a term is market has to be answered from the organization's own history.
• Definely does not currently publish pricing, and the product pages route evaluation to a demo booking, so there is no published figure to compare and no self-serve way to test first.
• Capability is split across five separately named products, so what a team actually gets depends on which modules the license covers.
• The Definely strength is concentrated on the document in front of the lawyer rather than on repeatable review standards applied across a portfolio of commercial agreements.

What is Spellbook?

Spellbook is an AI platform for commercial legal work, built around contract review, drafting, redlining, and negotiation.

Spellbook's Review feature works inside Microsoft Word, surfaces potential contract issues, and proposes redlines and comments as Track Changes attributed to the lawyer rather than to the tool. The Playbooks feature lets a legal team encode its own standards and review instructions, so the same positions get applied on every agreement instead of only the ones a senior lawyer touches. A team that has already written those positions down can carry an existing negotiation playbook into the product rather than starting from a blank rule set. The positions already exist, so the setup work is transcription rather than drafting.

The Draft feature helps generate clauses and agreements, including from the team's own precedent, which is the dividing line running through most contract drafting software: whether the first draft starts from the firm's own language or from a generic template. Starting from the firm's own language also means the output inherits whatever is already in that precedent set.

The Clause Library keeps that precedent searchable during both drafting and review. For teams that keep approved language in Word, a clause library inside the add-in removes the step of hunting through a shared drive mid-draft.

What does Compare to Market do?

Compare to Market sits alongside the Review and Draft features. It compares a provision with more than 20 million real market contracts across 270+ clause types, filtered by factors including industry, jurisdiction, and deal type. The output places the provision on a distribution of comparable terms rather than returning a verdict on it.

Who is Spellbook built for?

Spellbook suits teams handling a steady flow of third-party commercial paper, where the same review decisions recur across agreements.

For work that spans more than one agreement, Associate extends review and drafting across a whole document set rather than one open file. The practical case is a transaction: a term sheet that has to populate several agreements at once, or a target's contract set that has to be read for obligations before a deadline arrives. Due diligence exercises have the same shape, where the work is covering a set consistently rather than reading any single provision closely.

Pros

• Purpose-built for commercial contract review and redlining, with suggestions returned as native Track Changes the lawyer accepts or rejects.
• Compare to Market benchmarks a provision against real market contracts rather than against internal precedent alone, which answers a market-standard claim with comparables.
• Playbooks apply documented review positions consistently, so review outcomes vary less by reviewer.
• A seven-day free trial with no implementation project, so a lawyer can test it on real paper before a team purchase.

Cons

• There is no dedicated equivalent to Cascade. Defined terms and cross-references are handled within Review, so a team whose main problem is the internal structure of a long agreement is closer to what Definely is built for than to what Spellbook is built for.
• Pricing is quoted per team rather than published, which makes a fast side-by-side cost comparison harder.
• Spellbook is a commercial-contract specialist tool, not a legal-research platform, so case law research and citators sit with another product.

Spellbook vs. Definely at a glance

Where do Spellbook and Definely overlap?

The products overlap most around contract review and drafting. They separate once the problem becomes either structural document complexity or repeatable commercial negotiation workflow. Both sit inside the wider category of AI legal document review.

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What are the main differences between Spellbook and Definely?

1. Definely emphasizes complex-document control

The Definely products act on the structure of the agreement rather than on its commercial terms, and that changes where a lawyer's time goes on a long document. Tracing one defined term through a ninety-page facility agreement usually means scrolling away from the provision, reading the definition, and scrolling back to find the place again. Definely Read removes that round trip, which is why the suite fits banking, finance, and complex corporate work more naturally than high-volume commercial paper. On a short services agreement there is little to trace, so the time saved is smaller and the advantage over a general review tool narrows.

Cascade addresses the failure mode that follows an edit. A lawyer who narrows a definition in the first clause then has to find every later clause leaning on it, and that sweep is easy to cut short under deadline pressure. The manual habit Cascade replaces is a find-and-check pass through the whole document after each round of markup.

Proof covers placeholders left in a sent version, inconsistently capitalized defined terms, and cross-references pointing at renumbered clauses. A senior lawyer still reads the document, and Proof runs the mechanical pass separately from the substantive one. The two passes look for different things.

Enhance answers questions about a complex agreement in natural language and ties each answer back to the provision it came from, which keeps the lawyer checking the source rather than a summary of it.

2. Spellbook emphasizes review positions and negotiation

Spellbook is differentiated by where it puts the lawyer's attention: the review position, and the negotiation that follows it.

The practical difference shows up in the shape a suggestion arrives in. When a team weighs redlining tools against each other, one practical question is whether edits land as Track Changes a lawyer accepts or rejects clause by clause, or as a separate report. A separate report has to be transcribed back into the document.

The Playbooks feature moves the standard out of one lawyer's head. Without a documented standard, review outcomes vary with which lawyer is available. A defined contract review process is what stops the outcome depending on who picks the file up. A team that already keeps its positions in a document is transcribing them rather than authoring them. A team without written positions has to decide them first, which is the longer part of the setup.

A manual first pass varies with whoever runs it. AI-assisted review applies the same documented positions on every agreement.

3. Spellbook compares terms against external market data

The Compare to Market feature answers a different question again. Internal precedent tells a lawyer what the organization has accepted before. A Playbook tells the lawyer what the organization prefers. Neither answers the counterparty who says a term is market, and on a contested provision such as a limitation of liability cap that is a claim a firm's own file answers poorly. Filtering the comparison by industry, jurisdiction, and deal type is what keeps the rebuttal specific, because a cap that reads as standard in one deal type does not necessarily read that way in another.

4. Microsoft Word is not the main differentiator

Both products support substantive contract work inside Microsoft Word. The more useful distinction is what each helps the lawyer do there. Definely emphasizes navigation, document consistency, cross-references, and change impact. Spellbook emphasizes review, Playbooks, redlining, drafting, and market context.

How do Spellbook and Definely compare on pricing?

Definely does not publish standard pricing, and estimates vary by firm size, count, and deployment scope. The product pages direct prospective customers to book a demo to evaluate the suite and discuss access.

Spellbook uses customized pricing based on the number of team members on the license. The Spellbook pricing page also offers a seven-day free trial, so a lawyer can test the product on their own contracts before a team purchase. The evaluation path therefore differs even though neither vendor publishes a simple team list price. Definely is demo-led; Spellbook allows self-serve access first.

What should you compare besides seat cost?

When comparing quotes, weigh more than seat cost. Several factors change the real number:

• Which modules or capabilities the quote actually includes.

• Which document-management integrations are covered.

• What implementation, configuration, or data loading is required.

• What support looks like after the first month.

• How many lawyers realistically need a seat, as against how many would like one.

Settle two of these on the call. The first is whether the quote covers every module the evaluation actually relied on, which matters more for a five-product suite than for a single add-in, because a demo can run on a configuration the quote does not include. The second is in what format existing precedent and playbook material transfers in, not only whether it does.

It is also worth agreeing internally on who signs off before the quote arrives. Seat count is often a legal-operations or practice-management decision rather than a reviewing lawyer's.

Which should you choose: Spellbook or Definely?

Frame the decision around the documents and the tasks consuming the team's time.

Choose Definely if

• Lawyers regularly work on long, structurally complex agreements.

• Defined terms and cross-references consume much of the review time.

• Understanding the downstream impact of a contractual edit is a recurring problem.

• Legal-specific proofreading is a high priority.

• The organization holds an internal precedent repository it wants lawyers to reach directly from Word.

• That repository already sits in iManage, NetDocuments, or SharePoint, which are the systems Vault connects to.

Banking, finance, complex corporate transactions, and other practice areas built on dense, interconnected agreements are natural examples.

Choose Spellbook if

• The team handles a steady volume of commercial agreements.

• First-pass review and redlining are major bottlenecks.

• Review positions need to be applied consistently through Playbooks.

• Lawyers frequently draft or revise clauses from precedent.

• Negotiations regularly turn on whether a term is common in comparable agreements.

• Legal work needs to extend across a document set rather than a single Word file.

• More agreements arrive on the counterparty's paper than go out on the team's own templates, so the review position matters more than the first draft.

Vendor agreements, nondisclosure agreements, services agreements, sales contracts, and other recurring commercial paper are typical examples.

Is there a case for licensing both?

The two products can serve different parts of the same transactional workflow. A team handling both complex long-form agreements and high-volume commercial paper may find value in each, provided the additional capability justifies another system. Teams weighing a wider field than these two can start from the broader set of Spellbook alternatives and work inward.

Spellbook vs. Definely FAQs

Does Definely connect to document management systems?

Yes. Definely Vault connects to internal repositories and document management systems, including iManage, NetDocuments, and SharePoint, so lawyers can retrieve precedent language while working in Word.

Can Spellbook use a team's existing precedent?

Yes. Spellbook can work from preferred precedent alongside Custom Playbooks to support drafting and review. Teams can also connect existing document sources through the available Spellbook integrations.

Does Definely offer market benchmarking?

The published Definely product materials describe internal precedent, document analysis, navigation, proofreading, and change-impact analysis. Spellbook separately offers Compare to Market for comparing provisions with similar agreements outside the organization's own precedent set.

Can a firm run both Spellbook and Definely in Word?

Both are Microsoft Word add-ins, so both can be installed for the same user. Whether they sit comfortably together depends on the firm's own Word build and add-in policy, which is worth testing during the trial rather than assuming either way. IT and practice management usually own that decision, not the reviewing lawyer.

How does this compare with other Spellbook head-to-heads?

The axis changes with the competitor. Against Definely the question is document structure versus negotiation position; against a drafting-led product the question is grounding data, which is the split covered in Spellbook vs. Legora.

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Test the workflow that matters most

A practical way to choose between Spellbook and Definely is to test the type of document that represents the problem you need to solve.

What should you test first?

If the difficulty is navigating a long agreement, validating cross-references, or understanding the consequences of a change, evaluate Definely on that type of document. If the bottleneck is first-pass review, redlining, drafting, or negotiation, test that workflow instead, and see what market comparison adds on the provision your counterparties push back on most.

The more relevant product is the one that addresses the contract work your lawyers repeatedly spend time doing.