Claude Legal Plugin
Your AI Contract Reviewer
Most founders handle contracts one of two ways. They pay a lawyer $300 an hour and wait a week. Or they skim it, hope nothing is buried in clause 14, and sign. Anthropic released the Claude Cowork Legal Plugin on January 30, still in early access, and Wall Street immediately understood why both of those options are now optional. Thomson Reuters fell 18% in a single day, the largest intraday drop in its history. Over $300.6 billion in software market value was wiped across State Street SPDR ETFs tracking software services in 48 hours (Wall Street Journal). This is the exact setup. Five workflows you can run on real contracts tonight. Four minutes per review. Free on any paid Claude plan.
I used to send every NDA to a lawyer and wait three to five days.
Not because the NDAs were complicated. Most were standard. The lawyer would come back, charge somewhere between $300 and $600, and say it looked fine with maybe one or two small suggested edits. I paid for the certainty. Not the expertise. The certainty that I had not missed anything.
Most founders I know do one of two things with contracts. They send it to a lawyer and wait. Or they skim it and sign and quietly hope there is nothing weird in clause 14. Both options are bad. One costs money and time you do not have. The other is just gambling.
Last month I stopped doing either.
What happened in January
Anthropic released the Claude Cowork Legal Plugin on January 30. They buried it inside a broader product update. The legal tech industry noticed almost immediately.
Thomson Reuters lost 18% of its stock value in a single day, the largest intraday drop in the company's history. RELX, which owns LexisNexis, fell 14 to 15%. Over $300.6 billion in software market value was wiped across State Street SPDR ETFs tracking software services in 48 hours, according to the Wall Street Journal.
Wall Street understood what the plugin did before most founders did. It automated the part of legal work that was never really legal expertise. The contract admin. The clause scanning. The routine NDA that a junior associate was billing $300 an hour to read.
Something like 25 to 40% of a lawyer's working day goes to that work. Not strategy. Not courtrooms. Formatting documents, routing contracts, running compliance checks. That is what the market was pricing in.
What you will need
A paid Claude plan. Pro is $20 a month and that is all you need. The free tier does not support plugins or the Cowork desktop app.
Claude Cowork installed on your desktop. Download at claude.ai/download. The plugin runs inside Cowork, not inside the browser version of Claude. Web Claude does not have plugins.
Contracts to test. PDF or Word format both work. Start with something routine, an NDA or a supplier agreement. Not a live transaction with real money on the line.
That is it. No additional setup required.
The 4-step setup
Step 1. Download and install Claude Cowork
Go to claude.ai/download. Install like any other desktop app. Sign in with the same account as your Claude subscription. Cowork is a separate mode from the browser version. Once you open it you will see a sidebar with tabs. Plugins live there.
Step 2. Enable the Legal Plugin
Open Cowork. In the left sidebar, go to Plugins. Find Legal and click Enable. If you do not see it, check that Cowork is updated to the latest version. The plugin shipped January 30, 2026. Anything older will not show it.
That is the whole setup. Two steps.
Step 3. Upload your contract
In Cowork, start a new conversation. Drag your contract file in. PDF and Word both work. You have two ways to run a review: the plugin's native slash commands (faster, purpose-built) or natural language prompts (works for anyone on a paid Claude plan, with or without Cowork). Both are below.
Step 4. Read the output
Claude returns a clause-by-clause breakdown with three flags. Green means standard language, nothing unusual. Yellow means worth reading yourself before you sign. Red means a real lawyer should look at this specific clause before you proceed.
The rest of this playbook is below.
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After the flags, you get plain English redline suggestions on anything yellow or red. The whole thing takes about four minutes on a standard NDA.
The five workflows
Two paths. If you have the plugin installed in Cowork, use the slash commands. They are purpose-built for the legal review workflow. If you are on any paid Claude plan without Cowork, paste the natural language prompts directly into a chat with your contract attached. Both produce the same output.
NDA review
Plugin slash command (Cowork):
/triage-ndaNatural language prompt (any paid Claude plan):
Review this NDA clause by clause. Flag each clause as green (standard, no issues), yellow (worth reading, potential concern), or red (unusual, potentially one-sided, recommend legal review before signing). After the scan, give me a plain English summary of anything flagged yellow or red and suggest specific redline changes.Supplier agreement
Plugin slash command (Cowork):
/vendor-checkNatural language prompt (any paid Claude plan):
Review this supplier agreement. I am the buyer. Flag any clauses that are unusually broad, that limit my ability to exit the contract early, that impose unusual liability on me, or that give the supplier rights over my data or IP. Flag each clause green, yellow, or red and suggest redlines on anything flagged.SaaS terms of service
Plugin slash command (Cowork):
/review-contractNatural language prompt (any paid Claude plan):
Review these terms of service. I am a business customer. Flag anything unusual about data ownership, termination rights, price change clauses, liability caps, or auto-renewal terms. Green, yellow, red for each clause. Plain English summary of the yellow and red flags.Employment contract
Plugin slash command (Cowork):
/review-contractNatural language prompt (any paid Claude plan):
Review this employment contract from the employee's perspective. Flag any non-compete clauses, IP assignment terms that seem broader than standard, unusual termination provisions, or anything that limits what the employee can do after leaving. Green, yellow, red per clause with suggested redlines.Quick summary before signing
Plugin slash command (Cowork):
/briefNatural language prompt (any paid Claude plan):
Give me a plain English summary of this contract in under 200 words. Then list the three things I most need to understand before signing. Then flag anything that should go to a real lawyer before I proceed.How to read the output
Green. Standard language you would find in most contracts of this type. You can move through the clause without stopping.
Yellow. Pause and read it yourself. Not necessarily a problem, but specific or unusual language you should understand before signing. The redline suggestion tells you what a more balanced version would look like.
Red. Do not sign this clause without talking to a lawyer. Unusual liability terms, non-standard IP assignments, restrictive non-competes, or termination clauses that could cost you money. The plugin tells you what the risk is. Your lawyer reviews the red flags only, not the whole document. That is where the time and cost saving comes from.
What this replaces
| Task | Before | With the plugin |
|---|---|---|
| NDA review | Send to lawyer, wait 3 to 5 days, pay $300 to $600 | 4 minutes, free on your Claude plan |
| Clause-by-clause scan | Lawyer reviews manually, hourly billing | Automated, colour coded, instant |
| Redline suggestions | Lawyer drafts, you review, you pay | Generated automatically, you approve |
| Supplier agreement | Read yourself or pay someone | Upload, slash command, review only the flags |
| SaaS terms | Sign without reading or pay for a legal opinion | Quick review, flag the unusual clauses |
| Employment contracts | Expensive, slow, often skipped entirely | Run it yourself, take the red flags to a lawyer |
Honest limits
This is early access. Anthropic still labels the plugin as a research preview. The feature set will evolve, and Anthropic explicitly advises against using it for regulated workloads. Treat it as a powerful first pass, not a finished legal product.
This is not legal advice. Claude is not a lawyer. If something serious surfaces in the red flags, take those specific clauses to a real lawyer. The plugin surfaces the issue. A lawyer advises on it.
Do not use this for high-stakes transactions. Complex M&A, active litigation, employment disputes with real money on the line, regulatory filings. Those still need a real lawyer for the whole document, not just the red flags.
Do not sign based on the output alone. This is the analytical layer between you and the decision. The decision is still yours.
What it replaces is the $300 an hour you were paying someone to read a standard NDA and tell you it looked fine. When you get a red flag, now you know exactly which clause to send your lawyer. Instead of "please review this whole contract," you send them "clause 9.3 flagged red, is this as unusual as it looks?" That is a 20-minute call, not a five-day engagement.
How I actually run this now
Before I sign anything, it goes through the plugin first. That is the rule. Does not matter how routine it looks. Standard NDA from a big company, supplier onboarding agreement, SaaS terms for a new tool we are paying for. Everything.
All green. Sign the same day. No further review needed.
Yellow flags. Read those specific clauses myself before deciding. Usually takes 10 minutes.
Red flags. Send the specific clause to a lawyer for a 20-minute call. Not the whole document.
My lawyer bill has dropped significantly since January. Not because I am using lawyers less on the things that need them. Because I am not paying them to read the things that do not.
What just got bigger
On May 12, 2026, Anthropic expanded the legal offering significantly. What launched in January as a single plugin is now a full practice area suite.
| What shipped May 12 | What it means |
|---|---|
| 12 practice area plugins | Specific tooling for M&A, employment, IP, compliance, real estate, and more. Not just general contract review. |
| 80+ legal agents | Purpose-built agents for tasks like due diligence, regulatory research, and contract negotiation prep. |
| 20+ MCP connectors | Direct integrations with legal databases, matter management systems, and document repositories. |
| Microsoft 365 integration | Claude runs natively inside Word, Excel, and Outlook. Draft contracts in Word, review them in the same window without switching apps. |
The five workflows in this guide cover the everyday founder use case. The May 12 suite is where this goes for teams doing real legal work at scale. Worth knowing it exists. Worth starting with the basics first.
What this changes
The legal industry has always had two tiers. People who could afford a lawyer on retainer for every contract, and people who signed things and hoped. The tier you were in was mostly a function of how much cash your business had.
That split is closing. Not because lawyers are going away. Because the clerical layer underneath legal work is now automated. And that clerical layer was always where most of the cost was.
You were never paying $300 an hour for legal expertise on a standard NDA. You were paying it for the absence of something you could not see. The confidence that you had not missed anything.
That is what the plugin gives you back. For free. In four minutes.
The founders who figure this out are going to run a tighter operation than the ones who do not. Not because they stopped using lawyers. Because they stopped using them for the wrong work.
