Definely vs Sonar Legal: how they compare in 2026
A lawyer working through a dense agreement will find a different center of gravity in these two Word products. Definely concentrates on understanding and maintaining the contract's structure: Read keeps definitions and references in view, Cascade traces the effects of a change, and Vault inserts precedent together with its related definitions and references. Sonar Legal combines drafting and playbook review with a whole document formatting workflow and a separate Outlook assistant. Its formatter proposes a style for every paragraph, which the user reviews before applying the chosen house style. Sonar also offers tabular extraction and knowledge hubs through its web application. Definely is the closer fit when the immediate problem is following dependencies and reusing language inside a complex transaction; Sonar brings formatting, contract revisions and email drafting into a broader office workflow.
At a glance
All 15 axes, side by side
The same grid applied to every vendor in the index, graded from public sources. Hover a grade to see what the letter means on that axis.
AI Centrality
How much of the product is actually AI. Whether the machine learning is the mechanism the buyer is paying for or a feature layered onto conventional software, and whether the vendor is specific about which is which.
Definely combines deterministic contract tools with generative analysis inside Microsoft Word. Read provides navigation through definitions and references, while Proof checks formatting and drafting errors. Vault retrieves precedent clauses from a connected repository. Enhance interprets contract language and proposes revisions, and Cascade follows the consequences of a change through related provisions. The company began with Word tools before adding modern generative AI, so navigation and proofreading retain a distinct function without models. The Claude connector extends those tools into another interface and describes its structural checks as reproducible. AI supplies content analysis and contextual drafting alongside the existing contract editor.
Sonar Legal combines AI drafting and review with everyday Word tools for definitions, error detection and formatting. Partner analyzes the open agreement, drafts clauses, prepares memoranda from attached research and responds to counterparty comments. Playbooks turn precedents or instructions into review rules, and Tables extracts selected fields across contract sets. The drafting workflow can compare a response enriched by a clause knowledge base with one generated without it. Definition navigation and parts of the document interface remain useful independently of generative output. Formatting also uses AI to suggest styles before a user applies them, so automation extends beyond writing new contract language.
Citation Accuracy and Hallucination Disclosure
Whether the vendor publishes measured accuracy on citations and assertions, grounds output to primary sources, and says plainly what its system does when it does not know. Legal has a documented public record of fabricated citations reaching filed briefs, so an untested claim of accuracy is not evidence.
Enhance links its answers to specific clauses and definitions in the contract material under review. Definely describes clause level indexing, retrieval augmented generation and several agents working together, with analysis focused on the active agreement and related files. Read separately exposes internal references and definitions so the lawyer can inspect their source. The Claude connector describes its structural checks as deterministic and returns their results through Claude. These mechanisms connect findings with contract text, but no measured legal accuracy result, test set or hallucination rate establishes how reliably the generative layer interprets that text. A review speed claim does not measure answer correctness.
Partner answers from the open agreement and attaches citations to its analysis. Playbook results show a pass or fail for each rule, a supporting contract passage and proposed replacement text. Tables links each extracted result to the exact clause or section and lets a reviewer correct it. For clause drafting, Jina embeddings identify relevant knowledge base clauses that accompany the request to the language model. The web application also returns citations for legal research across more than 100 jurisdictions, but the underlying law collections and update schedules are unspecified. There is no reproducible accuracy test covering those research answers or the contract extraction workflow.
Autonomy and Oversight Model
What the system decides on its own, what a lawyer must approve, and whether the vendor documents where the review point sits. A tool that drafts under review and a tool that files without one are different products and different risks.
The lawyer works with findings inside Word and decides how to revise the agreement. Cascade exposes its reasoning about affected clauses, while Enhance offers contextual answers and suggested text that can be inserted into the contract. Definely describes AI as supporting defined tasks while leaving legal judgment with the reviewer. Its ISO 42001 framework also includes human oversight. These features provide an inspectable review surface and an expressed division of responsibility. The circumstances that stop an agent, the exact scope of unattended decisions and the handling of an erroneous recommendation remain unspecified. A target for automating manual work does not itself define those operational limits.
Users initiate AI requests and decide when to insert or replace text in Word. Suggestions can become tracked changes or ordinary edits, with a chosen author and optional comment. Playbook creation pauses for clarification when instructions are ambiguous, and reviewers can exclude rules before running a check. Results have severity labels and individual revisions. Formatting presents a paragraph by paragraph review table before Apply changes the file. Outlook separates reading a thread from composing a reply, and insertion requires Compose Mode. These are tangible review controls, but the wider agentic task feature lacks a complete account of escalation, failure handling and actions requiring approval.
Operational and Outcome Evidence
Named, dated evidence that the product works in production at real firms or legal departments. Case studies with figures and identified customers count. Unattributed testimonials and launch announcements do not.
Definely identifies law firm and corporate users including Slaughter and May, Dentons, Shoosmiths, Shepherd and Wedderburn, Deloitte and Barclays. Its company material describes more than 150 enterprise customers and 40,000 active users in over 30 countries. The current home page includes a deployment account from Shepherd and Wedderburn's technology lead describing installation through Intune, alongside comments from legal and innovation leaders. The product also claims faster review, without connecting that figure to a dated customer study and a reproducible measurement method. Named adoption establishes use of the suite, while the contribution and error rate of each generative feature remain unmeasured.
TWL Law Group managing partner Bob Tseng describes using Sonar Legal for cross border transactions and credits its practical workflow and hands on coaching with improved efficiency. The testimonial identifies both the firm and the legal buyer, but gives no dated before and after measurement. Sonar also reports that 44 percent of users use the product more than five times daily, without a population, observation period or measurement method. Its claimed reduction of up to 80 percent in model token consumption concerns operating efficiency, not a measured improvement in legal outcomes. Other deployment examples in its startup application leave customer identities undisclosed.
Privilege and Confidentiality Posture
How client confidences are handled: attorney client privilege and work product treatment, segregation of one client matter from another, whether client data trains any model, and what the vendor commits to in writing rather than in marketing.
Definely's terms require both parties to protect confidential information with at least reasonable care and to return or destroy it on termination or written request. The privacy policy identifies Azure as a processor of user content, while the trust center offers a data processing agreement and access control material through an access request. These provisions establish a confidentiality framework, but do not explicitly prohibit training models on client content. The privacy policy permits service improvement, and feedback receives a separate broad usage license. Matter separation, attorney client privilege and work product handling remain unspecified. Detailed AI security information requires access approval.
The AI processing policy limits submitted text to the requested response and rules out training, fine tuning and future improvement by Sonar or its model providers. Requests are isolated from other users' requests. Hosted knowledge bases have row level security, with customer hosted and dedicated enterprise alternatives. The Marketplace license adds confidentiality duties for customer data and limits disclosures to representatives with a need to know. Stored playbooks, knowledge and usage information sit outside the simple transient request description. Privilege and work product receive no specific treatment, and the permission model does not explain matter walls or how connected repository restrictions carry into retrieval.
UPL and Professional Responsibility Posture
Whether the vendor is clear that it supplies a tool rather than legal advice, who its audience is, and how it addresses unauthorized practice of law, competence and supervision duties, and jurisdiction limits. ABA Formal Opinion 512 is the reference point. Where the advice line is not the duty a product raises, the axis is read through the nearest professional duty it does raise: judicial conduct rules and the reviewing duty for products sold only to courts, and the duty to bill for time actually spent for products that draft time entries.
Definely addresses lawyers at large law firms and corporate legal departments handling complex transactions. Its product position retains legal judgment with the professional while using AI for defined contract tasks. Read, Proof, Enhance and Cascade provide review tools inside Word rather than a consumer advice service. The terms nevertheless do not set out a distinct no legal advice boundary or connect product controls to competence and supervision duties under named professional rules. Jurisdiction limits for use are also unspecified. The firm's markets across multiple countries and its focus on transactional work identify the audience, without establishing a professional responsibility framework for each location.
Sonar Legal targets legal professionals, including law firms and corporate counsel, and its interface keeps drafting and revision work inside familiar office applications. Partner interprets clauses, identifies risks, prepares legal memoranda and generates replies to counterparty comments. Those functions support legal judgment, while tracked edits and source links give the practitioner a way to inspect the result. An explicit boundary between software output and legal advice is unspecified in the product policy and linked Marketplace license. The claim of support across more than 100 jurisdictions does not identify limits tied to professional admission, competence duties or supervision of nonlawyer users.
AI Governance and Bias Disclosure
Published governance over model behavior: who owns it inside the vendor, what is tested before release, and what is disclosed about disparate output across matter types, parties, or populations.
Definely holds ISO/IEC 42001:2023 certification, with Prescient Security identified as the auditor. The framework covers Enhance, Cascade and internal AI use, with a register recording each system, impact assessments, ownership and ongoing monitoring. Its stated scope includes fairness, transparency, human oversight and risk assessment across development and operation. Management reviews and internal audits support continuing governance. The description assigns ownership within the register but does not name the accountable person or role for model behavior. It also gives no measured results for differences across matter types or populations. Certification therefore establishes the management framework without exposing those evaluation outcomes.
Playbook authors can express preferred positions, acceptable fallbacks and unacceptable terms, then revise the proposed rules before sharing them. The guidance explains how vague instructions can cause the model to weaken an already favorable clause. This is useful control over an individual review, rather than an organization wide account of model governance. Sonar describes secure development practices based on Microsoft SDL and OWASP, but those practices concern software security. A person accountable for model behavior, release evaluation procedure, incident review process for incorrect legal answers and results across languages or legal systems are unspecified. The broad jurisdiction and language coverage claims therefore lack corresponding quality comparisons.
AI Safety and Data Stewardship
Retention, deletion, access control, and what happens to prompts and documents after they are processed. Whether the vendor states its subprocessors and its incident practice, or leaves the buyer to assume.
Definely's trust center covers access monitoring, backups, erasure, audit logging, incident reporting and vulnerability management. The terms require confidential information to be returned or destroyed on termination or written request. Its privacy appendix identifies Azure for user content and separate providers for analytics, licensing, payments and customer management, with advance notice before user content processors change. The general privacy retention rule follows service necessity and legal obligations, while organizational contact details can remain after a subscription ends. A specific prompt and output schedule and the retention practices of any underlying model provider remain unclear. The AI security whitepaper requires access approval.
AI requests pass through Sonar to selected model providers, with a promise that prompts and responses are discarded when the response is returned. Google Cloud hosts account services in Singapore, and Jina provides knowledge embeddings from Germany. Hosted knowledge bases, playbooks, templates and usage records have different persistence from those transient requests; application backups run hourly. The privacy policy retains information as needed without a fixed deletion schedule. Access protections include role based controls, account lockout, optional two factor authentication and remotely revocable sessions. A signed DPA is available on request. Specific backup erasure timing and a product incident notification timetable remain unspecified.
AI Liability and Recourse
What the vendor stands behind contractually when its output is wrong. Indemnities, caps, carve outs, insurance, and whether any of it is published or only reachable through a negotiated agreement.
Definely's terms cap each party's aggregate liability at fees paid or payable during the preceding 12 months. They exclude consequential, indirect and several other categories of loss. The warranty disclaimer expressly covers the accuracy, completeness and reliability of content generated with the software, alongside the software and support themselves. These are contractual limits on recourse rather than a performance warranty for an AI recommendation. No customer indemnity for third party claims arising from generated output or insurance commitment is identified. Confidentiality breaches can support equitable remedies under a separate clause, while the general liability framework remains subject to the agreement's stated cap and exclusions.
The License Agreement link on Sonar's Microsoft Marketplace listing leads to Microsoft's standard publisher contract. That contract includes a warranty of substantial conformity with the product instructions and defense against intellectual property and applicable law claims, with exclusions for customer data, other products and unauthorized modifications. Subscription liability is capped at the greater of the preceding 12 months' fees or $500,000; certain customer data breaches have a higher cap, and defense obligations have exceptions to the limits. These are Marketplace acquisition terms, whose applicability to a separately purchased subscription is unclear. A specific warranty for correct legal conclusions or generated contract language is absent.
Practice Systems Integration Depth
How deeply the product reaches into the systems legal work already lives in: document management such as iManage and NetDocuments, Word and Outlook, contract lifecycle management, matter management, e-billing, and court filing systems.
The suite operates within Word, with Read opening definitions and references, Enhance inserting suggested language and Vault bringing precedent clauses into the active agreement. Vault connects to document management repositories, including iManage and NetDocuments; the current product page also shows SharePoint. It can insert associated definitions and update references when adding a clause. A separate MCP connector exposes Definely tools in Claude, with sign in through a Definely account and enterprise enablement by IT. Installation and architecture material is available through the trust center. Detailed permission inheritance and the administrative configuration of each repository connection remain unspecified in the openly accessible product material.
Word installation works through Microsoft Marketplace or administrator deployment to selected users and groups. Partner reads the active agreement and writes accepted clauses or replacements back into it, including optional tracked changes and author names. Outlook reads a thread, prepares responses and inserts text into a compose window, with a separate feature for visible revisions. Agentic email tasks require additional tenant administrator consent, which must be revoked separately when the add in is removed. OneDrive and SharePoint supply knowledge material to the web application. Email code authentication cannot enable features requiring Microsoft 365 consent, and older volume licensed Office editions lack the required browser component.
Deployment Model and Data Residency
Where the software runs and where the data sits. Multi tenant cloud, single tenant, private deployment, on premises, and whether region of residence is a published option or an enterprise conversation.
Definely combines a Word add in with hosted services. Local architecture diagrams for Read, Proof and Vault are available through the trust center, which also identifies AWS infrastructure. The privacy policy names Azure as a processor hosting user content and lists possible personal data processing countries including Belarus, Lithuania, Sweden, the United Kingdom and the United States. Those general locations are not selectable contract data residency commitments. The product material does not identify which model runs in which region, distinguish storage from inference for every feature, or specify a tenant architecture. The available information therefore leaves the precise AI processing boundary unresolved.
Most Word processing takes place on the user's device, while explicitly initiated AI requests travel through Sonar's backend to model services. Google Cloud in Singapore hosts the manifest and authentication services, and the processor list places Jina embeddings in Germany. Hosted knowledge bases can use Google Cloud with row level security, a dedicated enterprise server or a customer's own environment. Dedicated application hosting is also an enterprise option. The locations used by Azure OpenAI, OpenAI, Anthropic, Vertex AI and optional OpenRouter routing are unspecified. The privacy policy permits transfers to Thailand and other jurisdictions, so local document editing does not mean every AI request remains local.
Security Certifications and Trust Center
Independent attestation a buyer can pull without a sales call: SOC 2, ISO 27001, penetration test summaries, a trust center with current reports and named scope rather than a badge image.
The certification disclosure is named, dated and attributed. ISO/IEC 27001:2022 was recertified in February 2026 by the British Assessment Bureau, now Amtivo, a UKAS accredited body, with the audit dated 4 February 2026 and zero major and zero minor nonconformities. SOC 2 Type 2 was recertified on 28 October 2025 under AICPA SSAE 18 standards, with Prescient Security named as auditor. ISO/IEC 42001:2023 is certified by Prescient Security, alongside Cyber Essentials and a GDPR program. A 2026 independent penetration test is summarized: it covered web applications, APIs, client side integrations and external network infrastructure, was benchmarked against the OWASP Top Ten, and found low overall risk with no critical, high or medium severity findings. The summary compares this with the prior year's results, which did include medium severity findings. A SafeBase trust center holds the SOC 2 report, penetration test report, architecture diagrams, privacy and security whitepaper and policy set behind a self serve access request rather than a sales gate.
Sonar describes encrypted transport, secure WebSocket connections, role based access, device management and regular security testing. Its internal access practices include hardware security keys, while customer sessions can use two factor authentication and are revocable. The architecture follows Microsoft SDL and OWASP guidance, which are development practices rather than independent company certifications. The processor page refers to SOC 2 Type II certified infrastructure for Jina embeddings, but does not establish an attestation covering Sonar's own application and operations. A named auditor, certificate or report period for Sonar is unspecified. Technical security explanations and the DPA request route are available without a sales demonstration.
Model Supply Chain Disclosure
Which models sit underneath, whose they are, where they run, and whether the vendor commits to telling customers when that changes. A legal buyer inherits every dependency it cannot see.
Definely describes several agents, retrieval augmented generation and clause level indexing as parts of its AI architecture. AWS appears in the trust center, and the privacy appendix identifies Azure as a host for user content. Those infrastructure names do not identify the foundation models used by Enhance or Cascade. The Claude connector is a separate integration through which Claude calls Definely's tools, rather than proof that Anthropic supplies every model inside the suite. No production model version is specified. Customer notice applies to changes in user content processors, but an equivalent promise covering every model change is not identified.
The AI provider list names Microsoft Azure OpenAI, OpenAI, Anthropic and Google Vertex AI. Customers can choose or exclude providers, and optional OpenRouter routing supplies an alternative when the primary provider is unavailable. Sonar says it disables providers that permit training and opts out of OpenRouter prompt and completion logging. Jina creates embeddings for clause retrieval before selected knowledge accompanies the drafting request. The guide describes direct and routed workflows, but does not identify model versions or map each feature to an exact model and processing region. A commitment to notify customers of every model substitution is also unspecified.
Commercial Transparency
Whether a buyer can learn what this costs without entering a sales process: published rates, the unit being charged, what sits behind an enterprise tier, and what implementation adds.
Definely sells software through individual orders and a demo led sales process. Its terms require annual payment in advance, define an initial 12 month term and provide for successive annual renewals. Orders can include software licenses, additional users and upgraded packages, with currency and fees set in the customer's account. The agreement permits limited trials or beta access at Definely's discretion without establishing a universally available free plan. No numeric rate or fixed charging unit is stated for the suite, and implementation costs are unspecified. The contractual payment structure is identifiable, while a buyer cannot calculate a subscription total from a standard rate card.
A permanent free plan includes unlimited definitions, ten monthly Error requests, ten Partner requests and five uses of Sonar playbooks. Value costs $61 per user monthly or $49 per month with annual billing, covering 100 Error and Partner requests and 50 playbook and formatting requests monthly. Premium costs $99 monthly or $79 per month with annual billing and adds unlimited Word usage plus Outlook. Those plans restrict playbooks and formatting to Sonar's supplied options. Enterprise uses a quote and adds the web application, custom playbooks, house styles and a prompt library. Implementation charges and a standard cancellation arrangement for direct subscriptions are unspecified.
Firm and Practice Coverage
Who the product is actually built for. AmLaw, midlaw, small firm and solo, in house departments, government and courts, and which practice areas are supported rather than merely claimed.
Definely targets large law firms, including Magic Circle and Am Law firms, and corporate legal departments at major enterprises. Its named settings include acquisitions, banking, insurance and complex commercial agreements. The suite focuses on an active contract and its related files, with tasks such as clause reuse, linked definition review, issues list extraction and analysis of changes across an agreement set. It is positioned for complex transactional work rather than high volume processing of routine contracts or lifecycle administration. That boundary distinguishes the product from a general legal assistant or a CLM platform, while its main working environment remains the lawyer's contract in Word.
The product serves solo practitioners, small and midsize firms and corporate legal departments, with Word and Outlook as the main working environments. Its practice examples include corporate transactions, acquisitions, commercial contracts, financing, litigation and tax. Tables handles bulk agreement review, while knowledge hubs reuse internal precedents and memoranda. Sonar claims legal research across more than 100 jurisdictions and formatting templates for over 150 languages, including bilingual layouts and Asian scripts. Specific legal source coverage and comparative performance by jurisdiction are unspecified. The installation guidance provides concrete Office version limits, and custom knowledge, playbooks and styles belong to the enterprise offering.
The 12 legal signals, side by side
Recorded rather than graded. These are the questions a practitioner has to answer before a tool touches a client matter, and the answers are taken from public material only.
Client Data in Training
Can material a lawyer puts into this product be used to train a model?
The software terms and general privacy policy do not state whether customer content may train models. Definely permits use of feedback without a confidentiality restriction, and its privacy policy allows service improvement and development of new products, without naming model training. An AI security whitepaper is available through a trust center access request, but its contents were not available for review and cannot establish a separate commitment.
Sonar's AI policy says submitted text is used only to generate the requested response, with no reuse for training, fine tuning or future improvement by Sonar or its model providers. Optional OpenRouter routing excludes providers that allow training, and prompt logging is disabled. The Marketplace license protects customer confidentiality but does not expressly prohibit model training. The separate privacy policy allows service improvement using account, usage and uploaded template information, without overriding the more specific AI request promise.
Prompt and Output Retention
How long does the product keep what a lawyer typed, and can that be set to zero?
Clause 9.4 of Definely's terms requires return or destruction of confidential information when the agreement ends or the other party makes a written request. The privacy policy separately retains personal information for service needs and legal obligations, including some organizational contacts after subscription termination. The contract supplies a customer instruction route, but no product setting defines a prompt and output window or an immediate zero retention configuration.
For AI requests, Sonar promises to discard the input and generated response immediately after returning the result, without keeping a prompt archive or cache. That fixed zero retention statement concerns the processing path. Playbooks, house styles, hosted knowledge bases and usage records can persist separately, with information kept as needed under the privacy policy and hourly application backups. Their deletion periods are unspecified. The general website claim of no metadata retention is broader than the usage logging described in the privacy policy.
Ethical Walls and Matter Segregation
Does retrieval respect the firm’s ethical walls, or can the model read across them?
Vault retrieves clauses and definitions from connected document management systems, including iManage and NetDocuments, and can insert them into a contract. Definely's trust center includes access control policies and monitoring material behind an access request. The accessible product information does not explain whether retrieval applies each user's source permissions at request time or how matter walls are enforced, so the existence of a repository connector does not resolve that boundary.
A playbook can remain private or be shared with every member of an organization; only its owner can edit a shared playbook. Standard hosted knowledge bases use row level security, and enterprise customers can have dedicated storage or host knowledge themselves. AI requests are processed separately and are not combined with another user's request. The Microsoft connection requires authorized users and tenant consent, but repository permission inheritance at retrieval time and formal matter conflict walls are unspecified.
Third Party Request and Subpoena Notice
If someone subpoenas the vendor for a firm’s data, does the firm hear about it first?
Clause 9.1 of Definely's software terms permits disclosure of confidential information only to the extent required by a subpoena, court order or governmental authority, after prompt notice to the other party of the intended disclosure. That contractual notice is distinct from the privacy policy's general permission to disclose personal data for legal reasons. No transparency report or volume of government requests accompanies the commitment.
The publisher contract linked from Sonar's Microsoft Marketplace listing requires notice before legally compelled disclosure, when notice is lawful, so the customer can seek a protective order. The same contract requires prompt notice of unauthorized use or disclosure of confidential information. Its scope is Marketplace orders. Sonar's own privacy policy separately permits disclosure required by law, regulation or court order without a corresponding notice sentence. A general request transparency report and equivalent direct subscription terms are unspecified.
Primary Law Corpus Provenance
Where does the law in this product come from, and does the vendor have the right to use it?
Vault draws precedent clauses and definitions from the customer's connected repository and clause library. Enhance uses the contract and related material to provide contextual responses, while Read links internal definitions and references. This identifies the customer supplied source collection, but does not establish a vendor supplied primary law database, a separate rights basis for foundation model training material or an update cadence for legal authorities.
The web research service claims coverage of more than 100 jurisdictions in their native languages, but does not identify the underlying court, legislation or publisher collections. Its drafting knowledge base contains more than 50,000 selected clauses, and customers can add their own agreements and memoranda. That clause library is not an identified primary law collection. Source citations help the user inspect an individual answer, while acquisition rights, refresh schedules and jurisdiction by jurisdiction completeness remain unspecified.
Good Law Verification
Does the product tell you when the authority it just cited has been overruled?
Definely checks internal references and defined terms in transactional agreements. It can map broken or circular references and expose the relevant contract text, but these functions do not determine the subsequent history of a court decision. No licensed citator or independent treatment signal is identified for external legal authority. The suite's principal context is drafting and reviewing an agreement, with the source material coming from the contract and connected precedents.
Legal research answers include citations, and the litigation offering refers to statutes, precedents and case law. Neither that description nor the research workflow identifies a commercial citator, a subsequent history calculation or an indicator that an opinion has been overruled. Contract passage links in Partner and Tables address a different question: where the answer or extracted field came from. They do not establish the continuing authority of a court decision used in a memorandum.
Refusal and Uncertainty Behavior
What does the product do when the answer is not in the corpus?
The Claude connector describes its structural tools as deterministic, with the same analysis producing identical results for the same input. That claim concerns reproducibility of the tools rather than a refusal rule for every generative response. Enhance and Cascade provide contract analysis and reasoning for review, but no defined abstention message or confidence indicator explains what occurs when the supplied material cannot support an answer.
When building a playbook from instructions or precedents, Sonar pauses and asks clarification questions if the instructions are ambiguous. The rule guidance also explains how an imprecise payment or confidentiality requirement can produce unwanted edits and shows how to preserve acceptable terms. These are concrete uncertainty controls for playbook construction. A comparable no answer path for unsupported legal research questions is unspecified.
High, medium and low labels in review results describe issue severity rather than calibrated confidence in the model's answer.
Fabricated Citation Record
Does a public court record exist addressing fabricated or hallucinated legal citations in output from this product?
No identified court order, opinion or disciplinary decision attributes fabricated citations to Definely or Defeyene Legal Solutions Limited. Damien Charlotin's AI Hallucination Cases database contains no match for either name in the tool field or wider case text as of October 15, 2026. The absence does not establish legal accuracy, and the product's principal use is transactional contract review rather than preparation of authorities for court filings.
No court record naming Sonar Legal or its former AutoDox name was identified in the AI Hallucination Cases database as of October 16, 2026. The product generates contract language and also offers research and memorandum assistance, so citations can enter legal work through several features. This result concerns identified court incidents, not a test of citation accuracy. Contract source links and the ability to inspect research citations do not establish that every answer is correct or current.
Bar Guidance Alignment
Has the vendor engaged in public with the ethics opinions its buyers are bound by?
Definely provides material about contract review risks and operates an AI management framework that includes human oversight. Those controls address product governance and the reviewer's role, but do not map the suite to a named bar opinion or professional regulator's guidance. ABA Formal Opinion 512, state bar requirements and Solicitors Regulation Authority or Law Society guidance are not identified as the governing framework for the product's use.
Sonar is built for legal professionals and provides review controls such as tracked changes, source citations and editable playbook rules. Its compliance materials discuss privacy, security practices and Microsoft deployment requirements. They do not map the workflow to named bar opinions or jurisdiction specific duties concerning competence, supervision, confidentiality or disclosure of AI use. Broad research coverage across many jurisdictions is a product coverage claim and does not establish alignment with each jurisdiction's professional conduct requirements.
Billing and Fee Posture
Does the vendor address what happens to the bill when the work takes an hour instead of six?
Definely associates its tools with faster contract review and less manual drafting work. Law firms are a principal customer group, so reduced work can affect matters performed for clients rather than only an internal department's costs. The suite's contract reports and issues lists do not form a matter billing record, and no guidance specifies how a firm should adjust fees or disclose AI assisted work to a client.
The law firm offering emphasizes faster drafting, formatting and review, with TWL Law Group describing efficiency in cross border work. Sonar's pricing and token efficiency claims address the software cost rather than how a lawyer charges a client. Usage analytics can count generated clauses, errors and active users, but no client invoice record separates machine effort from lawyer review. Guidance on passing subscription charges through, reducing time entries or describing AI assisted work on a legal bill is unspecified.
Outside Counsel Guideline Readiness
Can a firm get this vendor through a client’s AI clause without a bespoke negotiation?
Definely's privacy appendix names Azure for user content, with advance notice before those processors change. It separately identifies analytics, payments, licensing and customer management providers. The trust center offers a data processing agreement, security reports, architecture material and AI security documentation through an access request. This gives a firm named processing information and a route to diligence material, without a dedicated client consent or notification pack.
The processor register names Google Cloud in Singapore and Jina in Germany, alongside the available language model providers and optional OpenRouter routing. Technical pages explain local processing, request transmission, authentication and knowledge hosting options. A signed data processing agreement is supplied on request. These materials can inform a firm's vendor assessment, but they do not form a client specific AI disclosure package. Exact model versions, all inference regions and a template for client approval remain unspecified.
Court Disclosure Support
If a judge’s standing order requires an AI disclosure, can the product produce one?
The Claude connector can return contract review results in HTML, DOCX and table formats, including issues and reference reports. Audit logging also appears in Definely's trust center. These artifacts support retention of findings, but no combined record identifies the model, retrieved sources and human verification for a particular court filing. The workflow remains centered on transactional agreements rather than certification under a judicial AI disclosure order.
Word users can apply an AI revision as a tracked change with a chosen author and optional comment, or insert it without tracking. Playbook results include the supporting contract passage and the proposed replacement. Tables links extracted values back to their source, and Outlook has a separate feature for visible revisions. These features preserve parts of review work, but do not create an immutable record of prompts, model versions and lawyer approval. A court disclosure export or filing template is unspecified.
The questions both sides leave open
Derived from the records above rather than written, so it cannot favor either vendor. Take these into both conversations and ask each side the same question.
- Good Law Verification
- Bar Guidance Alignment
Which one fits
Choose Definely if
- A negotiated amendment may affect several definitions and linked provisions. Cascade exposes those connections and its reasoning while the reviewer remains in Word.
- Your team wants to reuse a clause without losing its supporting definitions. Vault retrieves precedent, shows a comparison and updates associated references as the language enters the agreement.
- Reviewers need a structured list of unfinished work. Proof brings placeholders, brackets, comments and highlights into a gaps list and can replace sensitive details before external sharing.
Choose Sonar Legal if
- Applying a consistent house style to an inherited agreement is a recurring task. Sonar proposes formatting across all paragraphs and lets the reviewer change individual style assignments before applying them.
- Legal email is part of the same daily workload. The Outlook add in reads a thread, prepares a response and offers a separate tracked revision feature for feedback between lawyers.
- The team wants to create review rules from a precedent or written instructions. Sonar asks clarification questions, allows rule selection and returns source passages alongside proposed changes.
In summary
Definely
Definely supports complex contract review through Read, Proof, Cascade, Enhance and Vault. For practitioners following interconnected clauses in Microsoft Word, the AI Legal Index highlights Cascade's explanation of how changes affect definitions, provisions and references. Vault retrieves language from connected repositories and inserts related definitions with the selected clause. Proof collects missing information and checks drafting consistency.
Sonar Legal
Sonar Legal's Partner works with the open agreement, while playbooks return rule results, supporting passages and replacement text. The user can apply edits with or without tracked changes. Format presents paragraph style suggestions for review, and Outlook adds thread analysis, response drafting and visible revisions. Custom house styles and playbooks belong to the quoted enterprise offering.
Questions buyers ask
Does Sonar's formatter do the same job as Definely Proof?
Sonar's formatter assigns a chosen stylesheet across an agreement, including monolingual and bilingual layouts, through a paragraph review table. Definely Proof checks consistency, missing information and formatting defects. Both can help finish a contract, but applying a house style and checking drafting problems are separate tasks. From the AI Legal Index, based on each vendor's own published materials as of October 16, 2026. No vendor pays for placement.
How does each product help when a clause change has wider consequences?
Definely Cascade identifies provisions, definitions and references affected by a change and lets the lawyer inspect its reasoning. Sonar analyzes the active agreement and applies playbook rules with citations and replacement language. Sonar's current workflow does not describe an equivalent dedicated dependency analysis feature. From the AI Legal Index, based on each vendor's own published materials as of October 16, 2026. No vendor pays for placement.
Which product extends into Outlook email drafting?
Sonar has a separate Outlook add in for thread summaries, drafting, rewriting and visible revisions. Its Read Mode cannot insert text into an email; the user must open a compose window. The Definely suite compared here centers on contract work inside Word. From the AI Legal Index, based on each vendor's own published materials as of October 16, 2026. No vendor pays for placement.
Can a lawyer inspect Sonar's playbook findings before applying them?
Each rule result carries a pass or fail, a supporting passage and proposed revision. For this specific review workflow, the AI Legal Index identifies the user's Replace action and tracked change option as concrete inspection controls. A reviewer can also remove rules from a run.
Neither vendor paid for inclusion, placement or a grade, and neither reviewed this page before it published. Everything on it comes from public material on the dates shown. How the index grades.
Sonar Legal is operated by AutoDox Co., Ltd. Custom Sonar formatting and playbooks require enterprise packaging. The comparison concerns current product workflows, not a measured accuracy contest. Neither vendor reviewed this page.