Definely and Spellbook are both Microsoft Word add-ins for transactional and in-house lawyers, and both cost a fraction of an enterprise platform like Harvey or Legora. That is where the resemblance ends. Spellbook generates — it writes first drafts, proposes redlines, and flags missing clauses from AI models trained on commercial contracts. Definely makes the document you already have accurate and navigable — it pulls defined terms and cross-references into a side panel, proofs for definition and reference integrity, and (via Cascade) traces the knock-on effects of a single edit. The routing question is which bottleneck you are buying down: producing markup faster, or trusting that the markup you produced is internally consistent.
Where Spellbook wins
Generation from a blank page. Spellbook writes. Point it at a contract type and it produces a draft, suggests fallback clauses, and benchmarks against 2,300+ contract types using general legal training — no firm precedent library required. Definely’s strength is the opposite end of the workflow: it assumes a document already exists and makes that document better.
Speed to first markup on novel agreements. Because Spellbook generates from general legal knowledge rather than retrieving from a corpus, it produces reasonable language on contract types your firm has never seen — an early-stage AI licensing deal, a one-off data-processing addendum. Definely’s Vault search is only as good as the precedent already sitting in your DMS.
An agent that runs multi-document work. Spellbook Associate — the browser-based agent bundled with Suite licenses — can draft, review, and negotiate across a set of documents from a single instruction. Definely shipped its own agentic layer (Enhance) in May 2026, but the company’s historical center of gravity is assistive review, not autonomous generation.
Published price anchors. Spellbook’s tiers — roughly $99/user/month solo, ~$149 team — give a small firm a working number without a sales call. Definely publishes nothing.
Where Definely wins
Accuracy and integrity, not speed. Definely’s Proof sweeps for the errors that survive a fast draft: inconsistent defined terms, broken cross-references, stray drafting notes, punctuation drift. For a team whose real risk is a wrong cross-reference in an executed agreement — not a slow first draft — this is the load-bearing capability Spellbook doesn’t center.
Navigation of dense documents. Definely’s original feature pulls any defined term or cross-reference into a side panel without scrolling away from the clause you are reading. On a 120-page credit agreement with nested definitions, that is the difference between a five-minute check and a lost afternoon. Spellbook has no equivalent navigation layer.
Cascade traces knock-on effects. Cascade, launched August 2025, flags the 1st-, 2nd-, and 3rd-order implications of a single change across clauses, definitions, and schedules — the downstream breakage a redline assistant won’t catch. Spellbook suggests the edit; it doesn’t tell you what else the edit just broke.
Adoption is the differentiator. Definely runs as a thin Word add-in over documents opened from any DMS, with minimal training. For firms where past legal-AI pilots died on adoption friction rather than output quality, that matters more than raw model capability. Named users include A&O Shearman, Slaughter and May, DLA Piper, and Dentons, plus in-house teams at BT Group and Deloitte.
Procurement posture for DACH and UK. SOC 2 Type 2, ISO 27001, ISO 42001, and GDPR clear the questions European procurement asks first. Spellbook is SOC 2 Type II but does not carry ISO 42001.
Pricing reality
Spellbook’s pricing is the more knowable of the two, though it de-published exact figures after a late-2025 increase. The bands third-party trackers report: ~$99/user/month solo (capped at 50 contracts/month), ~$149 team, and ~$199–350/user/month enterprise with a 10-seat minimum and a 6-month commitment. At 10 seats, enterprise lands roughly $24K–42K/year before discounts. Spellbook Associate is bundled into Suite licenses, not a separate line item.
Definely is fully sales-led — no public per-seat number. The one lever it gives you that Spellbook does not: it sells single-seat subscriptions to individual lawyers, so you can establish a per-lawyer baseline before negotiating the enterprise figure. Get the per-seat price, the seat minimum, and the renewal-year uplift in writing during procurement. Both tools sit well below the ~$30K/year floor where Harvey and Legora start, before change-management overhead.
Implementation effort
Both install as Word add-ins and skip the multi-month rollout of a CLM or a research platform. Spellbook’s ramp investment is uploading your playbooks so it compares against your standards rather than its defaults; a team can be live in an afternoon. Definely’s ramp is connecting the DMS (iManage, NetDocuments, SharePoint) so Vault can search your precedent — Draft and Proof work immediately, but Vault’s value scales with what you connect. Neither carries the document-ingestion tax of a precedent-retrieval engine like DraftWise, where the clause suggestions stay generic until the historical library is loaded and indexed.
Verdict
Pick Spellbook when your bottleneck is producing drafts and redlines — you need clause generation, missing-term flags, and first-pass markup, especially on contract types where you have no precedent, and you want a price you can evaluate without a procurement cycle.
Pick Definely when your bottleneck is accuracy and navigation — heavily cross-referenced agreements where a broken definition is the real risk, lawyers who live in Word and have rejected past tools on friction, or a European procurement gate that wants ISO 42001. Its agentic generation (Enhance) is newer than Spellbook’s; weigh it on your own documents rather than assuming parity with Spellbook Associate.
Pick neither if your need runs past contract drafting and review into legal research, due diligence, or litigation prep — Harvey and Legora cover that, at materially higher cost and a real rollout.
The default for a team buying one tool first: name the bottleneck. If you spend more time writing contracts, Spellbook. If you spend more time making sure the contract you already wrote holds together, Definely. Most transactional teams have both problems — start with the one that is currently costing you a deal or a late night, and add the second once the first is handled.
Definely and Spellbook are both Microsoft Word add-ins for transactional and in-house lawyers, and both cost a fraction of an enterprise platform like Harvey or Legora. That is where the resemblance ends. Spellbook generates — it writes first drafts, proposes redlines, and flags missing clauses from AI models trained on commercial contracts. Definely makes the document you already have accurate and navigable — it pulls defined terms and cross-references into a side panel, proofs for definition and reference integrity, and (via Cascade) traces the knock-on effects of a single edit. The routing question is which bottleneck you are buying down: producing markup faster, or trusting that the markup you produced is internally consistent.
Where Spellbook wins
Generation from a blank page. Spellbook writes. Point it at a contract type and it produces a draft, suggests fallback clauses, and benchmarks against 2,300+ contract types using general legal training — no firm precedent library required. Definely’s strength is the opposite end of the workflow: it assumes a document already exists and makes that document better.
Speed to first markup on novel agreements. Because Spellbook generates from general legal knowledge rather than retrieving from a corpus, it produces reasonable language on contract types your firm has never seen — an early-stage AI licensing deal, a one-off data-processing addendum. Definely’s Vault search is only as good as the precedent already sitting in your DMS.
An agent that runs multi-document work. Spellbook Associate — the browser-based agent bundled with Suite licenses — can draft, review, and negotiate across a set of documents from a single instruction. Definely shipped its own agentic layer (Enhance) in May 2026, but the company’s historical center of gravity is assistive review, not autonomous generation.
Published price anchors. Spellbook’s tiers — roughly $99/user/month solo, ~$149 team — give a small firm a working number without a sales call. Definely publishes nothing.
Where Definely wins
Accuracy and integrity, not speed. Definely’s Proof sweeps for the errors that survive a fast draft: inconsistent defined terms, broken cross-references, stray drafting notes, punctuation drift. For a team whose real risk is a wrong cross-reference in an executed agreement — not a slow first draft — this is the load-bearing capability Spellbook doesn’t center.
Navigation of dense documents. Definely’s original feature pulls any defined term or cross-reference into a side panel without scrolling away from the clause you are reading. On a 120-page credit agreement with nested definitions, that is the difference between a five-minute check and a lost afternoon. Spellbook has no equivalent navigation layer.
Cascade traces knock-on effects. Cascade, launched August 2025, flags the 1st-, 2nd-, and 3rd-order implications of a single change across clauses, definitions, and schedules — the downstream breakage a redline assistant won’t catch. Spellbook suggests the edit; it doesn’t tell you what else the edit just broke.
Adoption is the differentiator. Definely runs as a thin Word add-in over documents opened from any DMS, with minimal training. For firms where past legal-AI pilots died on adoption friction rather than output quality, that matters more than raw model capability. Named users include A&O Shearman, Slaughter and May, DLA Piper, and Dentons, plus in-house teams at BT Group and Deloitte.
Procurement posture for DACH and UK. SOC 2 Type 2, ISO 27001, ISO 42001, and GDPR clear the questions European procurement asks first. Spellbook is SOC 2 Type II but does not carry ISO 42001.
Pricing reality
Spellbook’s pricing is the more knowable of the two, though it de-published exact figures after a late-2025 increase. The bands third-party trackers report: ~$99/user/month solo (capped at 50 contracts/month), ~$149 team, and ~$199–350/user/month enterprise with a 10-seat minimum and a 6-month commitment. At 10 seats, enterprise lands roughly $24K–42K/year before discounts. Spellbook Associate is bundled into Suite licenses, not a separate line item.
Definely is fully sales-led — no public per-seat number. The one lever it gives you that Spellbook does not: it sells single-seat subscriptions to individual lawyers, so you can establish a per-lawyer baseline before negotiating the enterprise figure. Get the per-seat price, the seat minimum, and the renewal-year uplift in writing during procurement. Both tools sit well below the ~$30K/year floor where Harvey and Legora start, before change-management overhead.
Implementation effort
Both install as Word add-ins and skip the multi-month rollout of a CLM or a research platform. Spellbook’s ramp investment is uploading your playbooks so it compares against your standards rather than its defaults; a team can be live in an afternoon. Definely’s ramp is connecting the DMS (iManage, NetDocuments, SharePoint) so Vault can search your precedent — Draft and Proof work immediately, but Vault’s value scales with what you connect. Neither carries the document-ingestion tax of a precedent-retrieval engine like DraftWise, where the clause suggestions stay generic until the historical library is loaded and indexed.
Verdict
Pick Spellbook when your bottleneck is producing drafts and redlines — you need clause generation, missing-term flags, and first-pass markup, especially on contract types where you have no precedent, and you want a price you can evaluate without a procurement cycle.
Pick Definely when your bottleneck is accuracy and navigation — heavily cross-referenced agreements where a broken definition is the real risk, lawyers who live in Word and have rejected past tools on friction, or a European procurement gate that wants ISO 42001. Its agentic generation (Enhance) is newer than Spellbook’s; weigh it on your own documents rather than assuming parity with Spellbook Associate.
Pick neither if your need runs past contract drafting and review into legal research, due diligence, or litigation prep — Harvey and Legora cover that, at materially higher cost and a real rollout.
The default for a team buying one tool first: name the bottleneck. If you spend more time writing contracts, Spellbook. If you spend more time making sure the contract you already wrote holds together, Definely. Most transactional teams have both problems — start with the one that is currently costing you a deal or a late night, and add the second once the first is handled.