Claude Legal Plugin: Setup, Permissions, and Review

A legal plugin for Claude is a browser extension, an MCP server, or a workflow integration that gives Claude access to legal resources, databases, or document workflows. Some help with research: they connect Claude to case law databases or citation tools. Others assist with drafting or review: they bring document templates, checklists, or firm-specific guidance into a Claude session. Each one has different access requirements and different output risks.

Legal work carries high stakes for errors. Any output Claude produces through a plugin needs verification against primary sources before you rely on it in a matter. Tools like fenbs let you keep the permitted instructions and review checklists that govern how Claude works on a matter, so every assistant you connect reads the same boundaries.

What a legal plugin for Claude is

The term "plugin" covers several things. In a browser, a plugin or extension might inject Claude into a legal research interface, letting you highlight text and ask Claude a question about it. In a development environment, a plugin might be an MCP server that connects Claude to a legal database API. In a document workflow, it might be an integration platform action that passes contract text to Claude for a review checklist.

Before you install or configure anything, understand what data the plugin accesses and where it sends it. A plugin that sends matter content to an external AI service may conflict with your confidentiality obligations. Check whether the service agreement covers privileged communications and whether your firm's policies allow it.

For background on Claude Code plugins and how plugins differ from skills and sub-agents, see those guides.

Evaluate a legal plugin before you connect it

Ask these questions before you give a plugin access to your Claude environment or your client data. Where does the data go? Does the plugin send content to a third-party server, or does it process everything locally? Who controls the API keys it uses? Can you revoke access without losing your work?

Check what the plugin adds and what it cannot do. A research plugin that searches a case law database is only as good as the database it queries, and its results need the same citation check you would apply to any source. A drafting plugin that fills in template language is producing a starting point, not a finished document.

Look for a plugin that names its data sources explicitly and provides citations you can follow. If a plugin gives Claude access to legal databases, verify that the databases are current and that the plugin returns the citation path, not just a summary.

Set up permissions and scope

Grant the narrowest scope the workflow needs. If you are using a plugin for research only, do not authorize it to write to any document store or case management system. If you are using it for drafting, limit it to the document types and matters where you have decided AI assistance is appropriate.

For MCP-based plugins, the connection goes through Integrations. You authorize the server with your AI assistant, set the tools it may call, and those boundaries hold for every session that uses it. A tool the server does not expose is a tool Claude cannot call, no matter what it is asked to do.

Verify the plugin's outputs

Every legal output from a plugin needs verification. Case citations should be checked against the original decision. Statutory text should be checked against the current version of the law. Contract clauses should be reviewed by a qualified reviewer before they go into a document that will be signed.

Do not treat a confident-sounding summary as a substitute for the primary source. Language models can produce plausible-looking text that misrepresents a case's holding, conflates jurisdictions, or relies on superseded law. The plugin reduces the time to first draft; it does not replace the review.

Build the review step into your workflow before you rely on the plugin in a matter. If the plugin helps with research, your review step is reading the cited source. If it helps with drafting, your review step is attorney review of the output. Make the review explicit so it cannot be accidentally skipped when you are under time pressure.

Keep permitted instructions in one place

The most useful thing you can do alongside a legal plugin is write down the instructions that govern how Claude may help on a given matter. Which resources may it access? Which output types require attorney review before use? What citation format does the firm use? What may not be sent to external services?

When those instructions live in a shared record, every assistant you connect reads them. You do not have to re-explain the firm's approach each session, and a different assistant picking up the matter starts from the same rules. Keep the instructions general enough to apply across matters; keep matter-specific context in that matter's own project.

How to do this with fenbs

1. Create a free account and set up a project for the matter or practice area where you are using the plugin.
2. Add the permitted use instructions to Decisions and rules: which resources the plugin may access, which output types need review, and what must not be sent externally.
3. Save your standard review prompts and citation-format instructions in Skills and prompts so Claude can retrieve them at the start of each session without you retyping them.
4. Connect your AI assistant over MCP from Integrations and point it at the project so it reads the rules before it uses the plugin.
5. After each session, ask the assistant to record any open tasks — citations to verify, clauses to review, questions for a partner — in the project so Where we left off reflects what is still outstanding.

fenbs does not keep client matter content. It keeps the instructions, prompts, and tasks that govern how Claude works. For related questions, see the guide on Claude for legal and Claude for legal research.