Claude Enters the Legal Market

Last week, I wrote about how open standards are reducing reliance on expensive legal AI platforms. That shift is happening even faster than expected. This week, Claude launched official plugins for knowledge workers, including a comprehensive Legal Plugin.

It was only a matter of time. Lawyers were already using Claude, just without dedicated legal functionality. Now is has that too. The Legal Plugin bundles skills that align with how legal professionals work.

First, what is Cowork?

The Legal Plugin runs within Claude Cowork, a new environment launched earlier this month. It works fundamentally differently from a standard chat interface.

In a normal conversation, you ask questions and get answers. Each interaction stands alone. With Cowork, you can assign Claude tasks to complete independently. You might say: analyse this contract against our playbook. Claude makes a plan, executes it, and presents the results. You can step away, make a cup of tea, and come back when it’s done (though it usually only takes a few minutes).

Cowork can access files on your computer, create and edit documents, and work for as long as needed. For more complex tasks, this is a significant step forward.

What are plugins?

Plugins are extensions that help Claude specialise in specific tasks.

Claude has launched eleven of them, covering functions like sales, finance, marketing, customer service and legal. They’re open source (available on GitHub) and can be installed in a few clicks.

The idea is that you don’t have to explain how you work every time. The Legal Plugin already knows what market practice looks like for a limitation of liability clause and how to screen an NDA.

What can you do with the Legal Plugin?

The plugin contains five commands, each representing a specific action you can trigger.

/review-contract analyses a contract against your playbook. Upload a document, provide context, and receive a clause-by-clause analysis with concrete redline suggestions.

/triage-nda screens NDAs. The plugin classifies them as green (standard, can proceed), yellow (specific issues to address) or red (full review required) based on its standard playbook, which you can customise.

/vendor-check shows the status of existing agreements with a supplier: which contracts are in place, when they expire, and what the key terms are.

/brief generates a briefing, whether that’s a daily summary of legally relevant items or a research briefing on a specific topic.

/respond generates a response based on your templates, useful for recurring questions like data requests, vendor enquiries or NDA requests.

How contract review works: the playbook concept

The contract review function deserves a closer look, as it illustrates how the plugin works.

The starting point is your playbook: a description of how your organisation approaches contracts. How do you handle liability? What range is acceptable? When should a lawyer review it?

Take limitation of liability as an example. Your playbook might specify a standard position of a mutual cap at twelve months’ fees, an acceptable range of six to twenty-four months, and an escalation trigger for unlimited liability or consequential damages without exception.

Claude analyses each relevant clause in the contract and classifies it as green, yellow or red.

Green means the clause aligns with your standard or better. No action required, perhaps just an informational note.

Yellow means the clause falls outside your standard but is negotiable. Claude provides concrete redline suggestions, an explanation you can share with the counterparty, and a fallback position if your initial request is rejected.

Red means escalate. Claude explains the risk, provides market-standard alternative language, and advises who should be involved.

The result is a structured analysis you can use directly in your negotiations. Not a summary you still have to work through, but a working document with clear priorities and concrete next steps.

Getting started

The Legal Plugin is available to anyone with a paid Claude subscription. Here’s how to install it: get a Claude Pro or Max subscription, download the Claude desktop app, open the app and go to the Cowork tab, then install the Legal Plugin via this link.

After installation, the commands are immediately available. Type /review-contract and upload a document to get started.

Customise it for your organisation

The plugin as delivered is a starting point. Its real power comes from tailoring it to your organisation.

Each plugin contains a configuration file where you can define your own playbooks. There you specify your standard positions for each clause type, the ranges within which you can negotiate independently, and the triggers that require escalation. The examples I gave above are exactly the kind of parameters you’d fill in there.

You can also add your own templates and connect the plugin to your existing tools (such as Microsoft 365).

If you want to go further, you can build your own plugins. Claude offers a dedicated tool for this: the Plugin Customiser, which guides you through the process step by step. You describe what you want, Claude asks questions about how you work, and generates a plugin that fits your workflow. Technically, you don’t need any coding knowledge for this (though it helps).

What this means

The Legal Plugin fits the picture I sketched last week. The barrier to specialised legal AI is lowering. What previously required in-house development or expensive platforms is becoming increasingly accessible.

For legal research, where you need up-to-date and reliable sources, specialised tools still add value (for now). But for contract review, NDA screening and compliance checks, the combination of general-purpose AI with the right plugin is becoming a serious alternative.

The bar for what you need to offer as a vendor to justify your price has just been raised considerably.

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