Generative AI is reshaping knowledge work, and law practices are no exception. Two of the most talked-about options are Microsoft Copilot for Microsoft 365 and Thomson Reuters CoCounsel. Both promise faster drafting, better research, and streamlined workflows—but they differ in depth of legal capability, governance, integrations, and cost. This week’s comparison breaks down where each shines, where the risks lie, and how to choose the right fit for your firm or legal department.
Table of Contents
- Overview of the Tools
- Features & Capabilities Comparison
- Compliance, Security & Risk Management
- Collaboration & Knowledge Sharing
- User Experience & Learning Curve
- Integration with Microsoft 365 and Other Legal Tools
- Pricing & Licensing Models
- Pros & Cons
- Best Fit Scenarios
- Side-by-Side Comparison Table
- Decision Framework: How to Choose
- Verdict
- Conclusion
Overview of the Tools
Microsoft Copilot for Microsoft 365 embeds generative AI directly into Word, Excel, PowerPoint, Outlook, Teams, OneNote, and more, leveraging your organization’s Microsoft Graph data (SharePoint, OneDrive, Teams messages, calendars, and emails) under your existing Microsoft 365 security and compliance controls. It is a broad productivity accelerator that helps with drafting, summarizing, analysis, and meeting support across daily workflows.
Thomson Reuters CoCounsel is a legal AI assistant purpose-built for legal work. It leverages Thomson Reuters’ legal content ecosystem (e.g., Westlaw, Practical Law) and task-specific workflows like legal research, document review, deposition preparation, drafting with citations, and contract analysis. It emphasizes legal accuracy, sources, and workflows over general productivity tasks.
Features & Capabilities Comparison
Drafting, Summarization, and Content Generation
- Copilot for Microsoft 365: Drafts and refines documents and emails using organizational content from SharePoint/OneDrive and context from Outlook and Teams. Strong for general drafting, meeting notes, and presentations.
- CoCounsel: Drafts legal documents, memos, research‑backed answers, and deposition questions with citations. Strong for legal argumentation and authority-backed outputs.
Legal Research and Citations
- Copilot for Microsoft 365: No native primary law database. Can summarize internal know-how, precedent banks, and knowledge libraries. Legal research requires integrations or linking to external systems.
- CoCounsel: Integrates with Westlaw content and legal citators. Generates answers with citations, provides supporting authorities, and assists with cite checking.
Document Review and Analysis
- Copilot for Microsoft 365: Summarizes files, compares versions, extracts bullets and action items, and assists in Excel data analysis. Useful for quick insights but not a specialized review platform.
- CoCounsel: Task flows for issue spotting, clause extraction, risk identification, and playbook-guided review; integrates with Thomson Reuters Document Intelligence for contract analysis.
Meetings and Communications
- Copilot for Microsoft 365: Robust meeting summaries, action item extraction, and follow-up drafting within Teams and Outlook.
- CoCounsel: Not primarily focused on real-time meeting workflows; geared toward legal tasks and research deliverables.
Governance and Knowledge Management
- Copilot for Microsoft 365: Inherits Microsoft 365 governance—permissions, labels, DLP, sensitivity, and eDiscovery—applied to prompts and retrieved content.
- CoCounsel: Offers legal task histories, citations, and source linking tailored for legal defensibility; governance depends on TR platform capabilities and your identity provider.
Expert insight: Think of Copilot for Microsoft 365 as an “everywhere accelerator” across your firm’s day-to-day work, and CoCounsel as a “legal specialist” that shines when you need cited answers, rigorous research, and structured legal workflows.
Compliance, Security & Risk Management
Copilot for Microsoft 365 processes data within your Microsoft tenant and respects existing access controls, sensitivity labels, DLP, retention, and audit logging. Prompts and outputs are not used to train foundation models. Copilot benefits from the broader Microsoft 365 compliance portfolio (e.g., Microsoft Purview, eDiscovery, Legal Hold, Insider Risk Management), making it attractive for firms that already rely on Microsoft certifications, regional data residency options, and contract addenda (such as HIPAA BAA where applicable with appropriate licensing).
Thomson Reuters CoCounsel provides enterprise security features like SSO via major identity providers, role-based access, logging, and commitments that customer data is not used to train public models. Thomson Reuters maintains industry-standard certifications (e.g., SOC 2/ISO family) across its platforms and emphasizes legal-grade provenance with citations. Data residency and retention options vary by product and region; review your statement of work to confirm specifics for your jurisdiction and client commitments.
Collaboration & Knowledge Sharing
- Copilot for Microsoft 365: Collaboration happens in-line where work already lives—Teams channels, SharePoint sites, and shared OneDrive libraries. Copilot can summarize conversation threads, pull context from shared documents, and respect team permissions.
- CoCounsel: Collaboration is centered on legal tasks and outputs (e.g., research memos, issue lists, deposition outlines). Firms often pair CoCounsel with TR HighQ or other matter management tools for broader sharing and workflow.
User Experience & Learning Curve
- Copilot for Microsoft 365: Minimal learning curve for users already in Word/Outlook/Teams. Prompt quality matters, but adoption is typically rapid due to familiar interfaces.
- CoCounsel: Purpose-built legal workflows reduce “prompt engineering” overhead for research and review tasks. Users learn a separate interface and task menu, which many find intuitive for legal use cases.
Integration with Microsoft 365 and Other Legal Tools
Copilot for Microsoft 365 integrates deeply with Microsoft apps and data via the Microsoft Graph. It can extend to third-party systems through connectors and approved partner integrations, enabling retrieval of content from external repositories (availability varies by connector vendor). This helps centralize knowledge access under existing Microsoft governance.
Thomson Reuters CoCounsel integrates across the TR portfolio—most notably Westlaw and Practical Law for content, and Document Intelligence for contract analysis. Roadmaps commonly include bridges into matter/collaboration platforms like HighQ and other legal tech. CoCounsel can operate alongside Microsoft 365; many firms export or link outputs back into SharePoint or Teams for matter files.
Pricing & Licensing Models
- Copilot for Microsoft 365: Licensed per user per month on top of eligible Microsoft 365 plans (e.g., Business Standard/Premium or E3/E5). Pricing is transparent and predictable at the seat level, making budgeting simpler for widespread rollout.
- CoCounsel: Typically quote-based per user or per workspace, with bundle options tied to Westlaw, Practical Law, or Document Intelligence. Cost often scales with content and feature tiers; confirm pricing, content entitlements, and usage terms in a formal proposal.
Tip: Factor internal costs such as change management, training, and governance. Copilot may be easier to deploy broadly; CoCounsel may deliver higher value per seat for research-heavy teams.
Pros & Cons
Microsoft Copilot for Microsoft 365
- Pros: Ubiquitous across daily tools; accelerates email, drafting, analysis, and meetings; inherits Microsoft 365 security/compliance; predictable licensing; quick adoption.
- Cons: Not a legal research engine; quality depends on internal content maturity and permissions hygiene; may require connectors for access to external DMS/knowledge bases.
Thomson Reuters CoCounsel
- Pros: Legal-specific workflows; citations and authority-backed outputs; leverage Westlaw/Practical Law; strong for document review and research-intensive matters.
- Cons: Separate system to learn and govern; pricing is less transparent; collaboration may rely on additional platforms; may require integration work to fit firm repositories.
Best Fit Scenarios
- Small to Mid‑Size Firms: Copilot for Microsoft 365 can uplift the whole firm’s productivity, especially where Teams/SharePoint are already in use. CoCounsel is compelling for litigation, appellate, or research-heavy practices.
- Enterprise Firms and Legal Departments: Many will deploy both—Copilot broadly for productivity and CoCounsel for high-stakes legal tasks. If you must choose, prioritize the system that addresses your primary bottleneck (email/meetings vs. research/review quality).
- Highly Regulated or Data-Sensitive Work: Copilot’s alignment with your existing Microsoft compliance stack may simplify audits and controls. CoCounsel’s citation-first outputs can support defensibility in legal work product.
Side-by-Side Comparison Table
| Aspect | Microsoft Copilot for Microsoft 365 | Thomson Reuters CoCounsel |
|---|---|---|
| Primary Focus | General productivity across Word, Outlook, Excel, PowerPoint, Teams | Legal research, drafting with citations, document review, deposition prep |
| Legal Research | No native case law; relies on your internal knowledge or integrations | Integrated with Thomson Reuters legal content (e.g., Westlaw, Practical Law) |
| Drafting Quality | Strong for general drafting and summarization based on tenant data | Strong for legal drafting with citations and authority-backed reasoning |
| Document Review | Summarize/compare documents; not a specialized review platform | Task-based review, clause extraction, risk detection; contract analysis via TR tools |
| Meetings & Email | Excellent meeting summaries and email drafting within Teams/Outlook | Not focused on live meetings; excels at legal task outputs |
| Security & Compliance | Inherits Microsoft 365 controls: labels, DLP, eDiscovery, audit, tenant boundaries | Enterprise controls, SSO, logging; legal-grade citations and provenance |
| Integrations | Deep Microsoft 365 integration; Graph connectors to many third-party systems | Tight with TR ecosystem (Westlaw, Practical Law, Document Intelligence); options for others |
| Adoption & Training | Low friction for Microsoft 365 users | Legal-task oriented; separate interface but intuitive for attorneys |
| Licensing | Transparent per-user add-on to eligible Microsoft 365 plans | Quote-based; bundles vary by content and features |
| Ideal Use | Firm-wide productivity uplift and knowledge access | Research-heavy work, cited drafting, document/intake review |
Copilot for Microsoft 365 Workflow Highlights
- Summarize Teams meeting → Generate follow-up emails → Draft motion outline in Word
- Analyze Excel damages model → Create slides in PowerPoint → Prep client update
- Search SharePoint matter site → Compile facts → Draft chronology
CoCounsel Workflow Highlights
- Pose legal question → Receive sourced answer with cases → Export memo
- Upload contract set → Run issue-spotting against playbook → Export risk report
- Generate deposition question sets → Link to authorities → Deliver outline
Decision Framework: How to Choose
Use this quick checklist to match the tool to your needs. If multiple items are true in both columns, consider a combined deployment.
- Primary Bottleneck:
- If email overload, meetings, and general drafting: favor Copilot for Microsoft 365.
- If research depth, citations, and legal review quality: favor CoCounsel.
- Content Posture:
- Robust internal knowledge base in Microsoft 365 (precedents, playbooks): Copilot gains leverage.
- Dependence on premium legal research content: CoCounsel gains leverage.
- Compliance Alignment:
- Desire to consolidate under existing Microsoft 365 controls and audits: Copilot fits cleanly.
- Need for citation-backed outputs and legal provenance: CoCounsel stands out.
- Rollout Strategy:
- Broad, firm-wide uplift with predictable seat pricing: Copilot.
- Targeted deployment to litigation/transaction teams for maximum ROI: CoCounsel.
- Integration Footprint:
- Microsoft 365-centric collaboration and matter storage: Copilot is native.
- Thomson Reuters ecosystem for research and contracts: CoCounsel is native.
- Change Management Capacity:
- Light-touch adoption in familiar apps: Copilot.
- Willingness to adopt a specialized legal tool for higher depth: CoCounsel.
Verdict
Copilot for Microsoft 365 is the best broad productivity accelerator for legal professionals living in Microsoft apps. It increases speed and consistency in everyday drafting, meetings, and analysis while inheriting mature Microsoft 365 compliance and governance. It is ideal for firm-wide rollouts and for surfacing your internal knowledge.
Thomson Reuters CoCounsel is the stronger legal specialist for research-backed answers, citation-driven drafting, and structured document review. It brings depth where legal precision matters most and aligns naturally with Westlaw, Practical Law, and TR’s contract tools.
Recommendations:
- Best for small firms seeking immediate, broad productivity lift: Copilot for Microsoft 365.
- Best for litigation and research-intensive teams: Thomson Reuters CoCounsel.
- Best for enterprise compliance and scale: Copilot as the foundation; add CoCounsel for high-value legal workflows.
Conclusion
Microsoft Copilot for Microsoft 365 and Thomson Reuters CoCounsel address different layers of legal work. Copilot accelerates everyday productivity within your existing Microsoft ecosystem, while CoCounsel delivers legal-grade depth with citations and structured workflows. Many firms will benefit from both: Copilot for breadth and CoCounsel for depth. Align the choice to your bottlenecks, content posture, and governance needs to maximize return on your AI investment.
Want expert guidance on improving your legal practice operations with modern tools and strategies? Reach out to A.I. Solutions today for tailored support and training.
