Cerebra Legal MCP Server

An enterprise-grade MCP server for legal reasoning and analysis based on the "think" tool concept from Anthropic's engineering blog.

Overview

Cerebra Legal provides three powerful tools for legal reasoning and analysis:

1. legal_think - A structured legal reasoning tool that helps analyze complex legal issues with domain-specific guidance and templates.
2. legal_ask_followup_question - A specialized tool for asking follow-up questions in legal contexts with domain-specific options.
3. legal_attempt_completion - A tool for presenting legal analysis results with proper structure and citation formatting.

The server automatically detects legal domains (ANSC contestation, consumer protection, contract analysis) and provides domain-specific guidance, templates, and feedback.

Features

• Domain Detection: Automatically identifies the legal domain of the analysis
• Domain-Specific Guidance: Provides tailored guidance for different legal domains
• Structured Templates: Offers domain-specific templates for legal analysis
• Citation Formatting: Properly formats legal citations
• Thought Quality Analysis: Provides feedback on legal reasoning quality
• Revision Support: Allows for revising previous thoughts

Installation

# Clone the repository
git clone https://github.com/yoda-digital/mcp-cerebra-legal-server.git
cd mcp-cerebra-legal-server

# Install dependencies
npm install

# Build the project
npm run build

Usage

Running the Server

npm start

Testing the Server

The repository includes a test client that demonstrates how to interact with the server:

# Make the test client executable
chmod +x test-client.js

# Run the test client
./test-client.js

The test client will:

1. Start the server
2. Send a tools/list request to get available tools
3. Send a legal_think request with a sample thought
4. Display the server's responses

Adding to Claude

To add the server to Claude, update your MCP settings file with the following configuration:

For VSCode Extension

Edit the file at ~/.config/Code/User/globalStorage/rooveterinaryinc.roo-cline/settings/cline_mcp_settings.json:

{
  "mcpServers": {
    "cerebra-legal": {
      "command": "node",
      "args": ["/path/to/mcp-cerebra-legal-server/build/index.js"],
      "disabled": false,
      "alwaysAllow": []
    }
  }
}

For Claude Desktop App

Edit the file at ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or the equivalent on your platform:

{
  "mcpServers": {
    "cerebra-legal": {
      "command": "node",
      "args": ["/path/to/mcp-cerebra-legal-server/build/index.js"],
      "disabled": false,
      "alwaysAllow": []
    }
  }
}

Using the Tools in Claude

Once the server is added to Claude, you can use the tools in your conversations:

System Prompt Integration

For optimal AI interaction with these legal tools, it's essential to include proper guidance in the system prompt. These tools follow the same AI → Human interaction model as standard Cline tools but with domain-specific enhancements.

The system prompt should include detailed documentation for each tool:

## legal_think
Description: A structured legal reasoning tool that helps analyze complex legal issues with domain-specific guidance and templates. This tool enables step-by-step legal analysis with feedback on reasoning quality.

Parameters:
- thought: (required) The current legal reasoning step
- thoughtNumber: (required) Current thought number in sequence
- totalThoughts: (required) Estimated total thoughts needed
- nextThoughtNeeded: (required) Whether another thought step is needed
- category: (optional) Legal domain category (auto-detected if not provided)
- references: (optional) Array of legal references
- isRevision: (optional) Whether this revises previous thinking
- revisesThoughtNumber: (optional) Which thought is being reconsidered
- requestGuidance: (optional) Whether to request domain-specific guidance
- requestTemplate: (optional) Whether to request a domain-specific template

Usage:

Your legal reasoning step here
Current thought number
Estimated total thoughts
true or false
Legal domain (optional)
Array of references (optional)
true or false (optional)
Thought number being revised (optional)
true or false (optional)
true or false (optional)

## legal_ask_followup_question
Description: Ask the user a legal domain-specific question to gather additional information needed to complete the task. This tool enhances the standard ask_followup_question with legal domain detection, terminology formatting, and domain-specific suggested options.

Parameters:
- question: (required) The question to ask the user. This will be automatically enhanced with appropriate legal terminology.
- options: (optional) An array of 2-5 options for the user to choose from. If not provided, domain-specific options will be automatically suggested.
- context: (optional) Additional context to help with domain detection and question formatting.

Usage:

Your question here

Array of options here (optional), e.g. ["Option 1", "Option 2", "Option 3"]

Additional context to help with domain detection (optional)

## legal_attempt_completion
Description: Present the result of your work to the user with proper legal structure and formatting. This tool enhances the standard attempt_completion with legal domain detection, document structuring, and citation formatting.

Parameters:
- result: (required) The result of the task. This will be automatically formatted with proper legal structure.
- command: (optional) A CLI command to execute to show a live demo of the result to the user.
- context: (optional) Additional context to help with domain detection and result formatting.

Usage:

Your final result description here

Command to demonstrate result (optional)
Additional context to help with domain detection (optional)

This guidance ensures the AI understands:

1. These are specialized versions of standard tools
2. They maintain the same AI → Human interaction flow
3. They have additional capabilities and parameters
4. How to properly format the tool calls

Without this guidance, the AI might not fully leverage the domain-specific capabilities built into these tools.

1. Using legal_think

The legal_think tool helps you analyze complex legal issues with structured thinking:

I need to analyze an ANSC contestation where a claimant argues that technical specifications in a tender were too restrictive.

Claude will use the legal_think tool to:

• Detect the legal domain (ANSC contestation)
• Provide domain-specific guidance
• Offer a structured template for analysis
• Give feedback on the quality of legal reasoning
• Support revision of previous thoughts

2. Using legal_ask_followup_question

When Claude needs more information to complete a legal analysis:

What specific provisions of the technical specifications are being challenged?

Claude will use the legal_ask_followup_question tool to:

• Format the question with appropriate legal terminology
• Provide domain-specific options for the user to choose from
• Detect the legal domain for context-aware questioning

3. Using legal_attempt_completion

When Claude is ready to present the final legal analysis:

Based on my analysis, the technical specifications requiring "minimum 5 years experience" appear disproportionate and likely violate Article 33(2) of Law 131/2015 on public procurement.

Claude will use the legal_attempt_completion tool to:

• Format the conclusion with proper legal structure
• Extract and format legal citations
• Organize the analysis into clear sections
• Provide a professional legal document format

Tool Input Schemas

legal_think

{
  "thought": "Analyzing ANSC contestation where claimant argues technical specifications were too restrictive.",
  "thoughtNumber": 1,
  "totalThoughts": 5,
  "nextThoughtNeeded": true,
  "category": "ansc_contestation",  // Optional, auto-detected if not provided
  "references": ["Law 131/2015", "ANSC Decision #12345"],  // Optional
  "isRevision": false,  // Optional
  "revisesThoughtNumber": null,  // Optional
  "requestGuidance": true,  // Optional
  "requestTemplate": true  // Optional
}

legal_ask_followup_question

{
  "question": "What specific provisions of the technical specifications are being challenged?",
  "options": [  // Optional, auto-generated if not provided
    "Are you challenging the experience requirements?",
    "Are you challenging the technical capacity requirements?",
    "Are you challenging the financial requirements?",
    "Are you challenging the certification requirements?"
  ],
  "context": "ANSC contestation regarding procurement of IT equipment"  // Optional
}

legal_attempt_completion

{
  "result": "Based on the analysis of ANSC contestation #12345, the technical specifications requiring 'minimum 5 years experience' appear disproportionate and likely violate Article 33(2) of Law 131/2015 on public procurement.",
  "command": null,  // Optional
  "context": "ANSC contestation analysis"  // Optional
}

Architecture

The server is built with a modular architecture:

• Domain Detector: Identifies the legal domain of the analysis
• Legal Knowledge Base: Provides domain-specific guidance and templates
• Citation Formatter: Formats legal citations properly
• Tool Implementations: Handles the logic for each tool

Development

Project Structure

mcp-cerebra-legal-server/
├── src/
│   ├── shared/           # Shared components
│   │   ├── DomainDetector.ts
│   │   ├── LegalKnowledgeBase.ts
│   │   ├── CitationFormatter.ts
│   │   └── types.ts
│   ├── tools/            # Tool implementations
│   │   ├── LegalThinkTool.ts
│   │   ├── LegalAskFollowupQuestionTool.ts
│   │   └── LegalAttemptCompletionTool.ts
│   ├── utils/            # Utilities
│   │   └── logger.ts
│   └── index.ts          # Main server entry point
├── build/                # Compiled JavaScript
├── test-client.js        # Test client
├── package.json
└── tsconfig.json

Building

npm run build

Testing

# Run the test client
./test-client.js

Repository

This project is available on GitHub at: https://github.com/yoda-digital/mcp-cerebra-legal-server

References

• The "think" tool: Enabling Claude to stop and think in complex tool use situations - Anthropic Engineering Blog

License

MIT

Shared threads will appear here, showcasing real-world applications and insights from the community. Check back soon for updates!