Key takeaways
- Business tiers of all three can be configured for confidential legal work. Consumer accounts cannot.
- Claude is often preferred for long-document review and drafting. ChatGPT for breadth. Copilot when matters live in Outlook and SharePoint.
- Court rules on AI differ by jurisdiction. Check every court you appear in.
- General assistants never replace checking authorities. Every citation is verified by a lawyer.
Law firms were among the first to be warned about AI and among the first to benefit from it. A small or mid-sized firm now has a straightforward decision in front of it: which general assistant to roll out to fee earners and staff, and how to configure it so client confidentiality holds. This page compares the three mainstream options for legal work. It is not legal advice on your professional obligations, which you should confirm with your regulator or law society.
How they compare for legal work
| Claude Team | ChatGPT Business | Microsoft 365 Copilot | |
|---|---|---|---|
| Long contracts and bundles | Strong, widely preferred | Strong | Good within Word and SharePoint |
| Drafting tone | Measured, needs less editing | Capable, can be wordy | Capable |
| Working from your own matters | Through projects and connectors | Through projects and connectors | Native, across mailbox and files |
| Spend and connector control | Org and user spend controls, connector control | Admin console, connector control | Microsoft 365 admin, Purview |
| Standard seat, USD per month, annual | 20 | 20 | Copilot Business listed at 21, on top of Microsoft 365 |
Where each one fits
Claude: review and drafting
Firms whose day is reading and drafting long documents, such as commercial, property and disputes practices, tend to prefer Claude's handling of large files and the tone of its drafts. The option to put a few heavy users on premium seats suits firms where a handful of lawyers do most of the document-intensive work.
ChatGPT: breadth across the firm
For a firm wanting one tool for lawyers, paralegals, business development and operations, ChatGPT's familiarity and range make adoption easiest. Most staff will already know how to use it.
Copilot: matters in Microsoft 365
If your matters live in Outlook and SharePoint, paid Copilot can summarise a matter's correspondence and draft from existing documents without anything being uploaded. That is powerful, and it depends entirely on matter permissions being right. Ethical walls and matter-level access must be correct before Copilot is switched on. See fixing SharePoint permissions before Copilot.
Confidentiality settings that matter
- Business tier only. No client information in personal accounts, ever.
- No training on firm data. Confirm the setting and record it.
- Retention. Know how long conversations are kept and who can see them.
- Single sign-on and offboarding. When someone leaves, their access ends that day.
- Connectors. Decide which systems the assistant may read. Matter management and document management connectors need particular care.
Court and regulator rules
Courts and regulators have issued guidance on generative AI, and it is not uniform. Examples include the Supreme Court of New South Wales practice note restricting AI use in affidavits, witness statements and expert reports, and the American Bar Association's formal opinion on lawyers' use of generative AI. Your firm's policy should name the rules that apply in the jurisdictions where you practise, and be reviewed when they change.
The non-negotiable rule: every authority, citation and quotation produced with AI help is checked against the source by a lawyer before it goes anywhere. Courts in several countries have sanctioned lawyers for filing invented citations.
General assistant or legal-specific tool?
Legal-specific platforms built on authoritative legal databases are valuable for research where the answer must be grounded in current law. They are also considerably more expensive per seat. For most small and mid-sized firms, the right sequence is a well-governed general assistant for everyone first, then a legal research tool for the lawyers who need it, once you know how much they will use it.
For the wider picture of AI in legal practice, read AI for law firms. For the client side, see AI clauses in client contracts and insurance.
Frequently asked questions
Is ChatGPT safe for lawyers to use?
The business and enterprise tiers can be used safely with the right settings and rules: no training on firm data, controlled retention, single sign-on, and a policy on what client information may be entered. Consumer accounts should not be used for client work.
Is Claude better than ChatGPT for legal work?
Many lawyers prefer Claude for long documents, careful drafting and close reading, and ChatGPT for breadth and research. Both are capable. The firm's document workflow and admin needs matter more than small differences in output quality.
Can we use AI for court documents?
Rules vary by court and jurisdiction, and some courts restrict or require disclosure of AI use in particular documents. In New South Wales, for example, a Supreme Court practice note limits the use of generative AI in affidavits, witness statements and expert reports. Check the rules of every court you appear in.
Do law firms need a legal-specific AI tool?
Not to start. A well-configured general assistant handles much of the drafting, summarising and review work. Legal-specific tools add value when you need answers grounded in authoritative legal databases or integration with practice management, and are worth assessing once the basics are in place.
Get a straight answer for your business
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