Claude and ChatGPT for lawyers: what works and what to watch

Claude and ChatGPT can draft, review contracts and research case law for lawyers, if you protect client data and check every citation.

Picks: 3; ranked

Yes, Claude is usable for legal work, and since May 2026 it is built for it: Claude for Legal adds 20+ connectors, including Thomson Reuters CoCounsel, Harvey, iManage and Free Law Project, plus practice-area plugins. ChatGPT works for drafting and research too. Two rules decide whether you can use either: ABA Formal Opinion 512, as reported by Zuva, requires informed client consent before you put client information into a self-learning AI tool, and every citation must be checked, as the $5,000 sanction in Mata v. Avianca showed.

Good for

In-house counsel triaging NDAs and vendor contracts
Litigators researching case law and building briefs
Solo and small-firm lawyers drafting letters and memos
Paralegals organising matters, dockets and documents

ChatGPT

ChatGPT is fine for first drafts and summaries. It has no legal research connector to match Claude's, so check every case it names.

Plan: A business plan for client work, after checking OpenAI's data terms with your firm.

What it can do

Draft letters, memos and clauses from your instructions
Summarise long documents you upload
Answer research questions, which you must verify against a primary source

Limits

A court order in NYT v. OpenAI made OpenAI keep ChatGPT output logs until September 26, 2025; logs saved under it and logs for accounts the New York Times flagged are still kept
Lawyers have been sanctioned for filing briefs with cases ChatGPT made up

Claude

Claude's May 2026 Claude for Legal launch added 20+ legal connectors and 12 practice-area plugins. Use a Team or Enterprise plan for client matters.

Plan: Team or Enterprise for client work: Anthropic does not train on commercial-plan data by default. The CourtListener connector is free with a CourtListener account.

What it can do

Review a contract against your playbook and draft redlines with Anthropic's legal plugin
Triage incoming NDAs as green, yellow or red
Search case law and check citations through Free Law Project's CourtListener connector
Work with CoCounsel Legal, Westlaw and Practical Law through the Thomson Reuters connector
Reach documents in iManage, NetDocuments, Box or Docusign through Claude for Legal connectors

Limits

The legal plugin says it does not give legal advice; a licensed lawyer must review its output
Its default playbook reflects US positions (Delaware, New York, California); change it for other jurisdictions
Consumer plans (Free, Pro, Max) have different training settings than Team and Enterprise

Plugs to turn on

CourtListener (Free Law Project): Free Law Project's own case-law connector with citation checks. Free with a CourtListener account.

Plugs worth turning on

Start with CourtListener for research. The Thomson Reuters, Harvey, iManage and NetDocuments connectors are in Claude's directory if your firm already pays for them.

Research case law and check citations with CourtListener

Claude

1
Add the connector
In Claude, go to Customize > Connectors > Browse Connectors, add CourtListener and grant access to your free CourtListener account.
Uses CourtListener (Free Law Project)

Ask a research question

Ask for real cases with citations and the court, so each one can be checked.

Prompt

Find Second Circuit decisions since 2015 on whether a forum selection clause in clickwrap terms binds a consumer. Give the case name, citation, date and a one-sentence holding for each.

3
Verify every citation
Ask Claude to check each citation against CourtListener, then open the opinions you will rely on and read them.
Prompt
```
Check every citation in my draft brief against CourtListener. List any you cannot find or whose holding does not match what I wrote.
```

Review a contract against your positions

1
Remove what you do not need to share
Get client consent first under ABA Opinion 512. Then strip names and deal terms that the review does not need.

Give your positions, then the contract

Paste your standard positions and attach the contract.

Prompt

Review this MSA from the customer's side against my positions below. For each clause that differs, quote it, explain the risk in one sentence, and propose replacement language. Rank issues high, medium or low.

3
Get a redline
In Claude Code, the Safe Docx plug edits the Word file directly so you get a marked-up copy back.
Uses Safe Docx

Triage an NDA with Claude's legal plugin

Claude

Install the plugin

In Claude Code, run:

claude plugin marketplace add anthropics/knowledge-work-plugins
claude plugin install legal@knowledge-work-plugins

In Cowork, add the legal plugin from the same marketplace.

2
Write your playbook
Create legal.local.md with your standard positions: term, governing law, non-solicit, residuals. In Claude Code it goes in your project's .claude/ folder; in Cowork, in a folder you share with it.
3
Run the triage
Attach the NDA and run the command. It sorts it into green (standard), yellow (counsel review) or red (significant issues).
Prompt
```
/triage-nda
```
4
Review before you sign
Read every flagged clause yourself. The plugin is a first pass, not legal advice.

Verdict

Use Claude on a Team or Enterprise plan with the CourtListener connector and Anthropic's legal plugin. Get client consent first, and verify every citation before it reaches a court.

Our pick: CourtListener (Free Law Project)

Claude is the stronger pick for legal work in 2026 because of its legal connectors and plugin. The limit is yours to manage: consent, confidentiality and checking citations.

Best for

Contract and NDA review against a playbook
Case law research with citation checks
Drafting letters and memos

Skip it if

You cannot get client consent for the data you would share
You would file anything without reading the cited cases

Questions

Can lawyers use Claude or ChatGPT?

Yes, with care. ABA Formal Opinion 512 lets lawyers use AI, but as reported by Zuva it requires informed client consent before putting client information into a self-learning tool, and you remain responsible for the output.

What is Claude for Legal?

Anthropic's May 2026 legal launch: 20+ connectors (Thomson Reuters CoCounsel, Harvey, iManage, NetDocuments, Docusign, Everlaw, Relativity, Free Law Project and others) and 12 practice-area plugins for areas like litigation, employment and privacy.

Is Claude confidential enough for client information?

On commercial plans, Anthropic does not use your inputs or outputs for training by default. That does not replace client consent under ABA Opinion 512 or your firm's own policy.

Is ChatGPT confidential?

Check the plan's data terms with your firm. A court order in NYT v. OpenAI made OpenAI keep ChatGPT output logs until September 26, 2025, and logs saved then are still kept.

Can ChatGPT or Claude make up case citations?

Yes. In Mata v. Avianca, lawyers were fined $5,000 in June 2023 for a brief with fake cases from ChatGPT. Check every citation, for example with the CourtListener connector, and read the opinions.

Is there a free legal research tool for Claude?

Yes. Free Law Project's CourtListener connector is free with a CourtListener account and searches case law, dockets and judges, with citation checks.

Can Claude connect to Westlaw or CoCounsel?

Yes, through the Thomson Reuters connector announced in May 2026, if your firm has CoCounsel Legal. It works alongside CoCounsel rather than replacing it.

Does the Claude legal plugin give legal advice?

No. Anthropic says it assists with legal workflows and its output must be reviewed by a licensed attorney.

Sources

Docs, issue trackers and discussions this page is built from.

Show all 10

Anthropic launches Claude for Legal · abajournal.com
Thomson Reuters and Anthropic expand partnership to connect Claude with CoCounsel Legal · thomsonreuters.com
ABA Formal Opinion 512 (as reported by Zuva) · zuva.ai
Phony ChatGPT Brief Leads to $5,000 Fine for NY Lawyers · news.bloomberglaw.com
OpenAI no longer has to preserve all of its ChatGPT data, with some exceptions · engadget.com
Legal plugin · github.com
CourtListener is now available inside Claude · free.law
Is my data used for model training? · privacy.claude.com
oktopeak/clio-mcp · github.com
usejunior/safe-docx · github.com