CourtListener MCP Server

A Model Context Protocol (MCP) server that provides LLM-friendly access to the CourtListener legal database and the Electronic Code of Federal Regulations (eCFR) through the official CourtListener API v4. This server enables searching and retrieving legal opinions, court cases, judges, legal documents, and federal regulations for precise legal research and citation verification.

🎯 Purpose

The CourtListener MCP Server provides comprehensive access to legal case data, court opinions, and federal regulations through the extensive CourtListener and eCFR databases. CourtListener contains millions of legal opinions from federal and state courts, while eCFR provides up-to-date federal regulations.

📋 Key Advantages

• Comprehensive Legal Database:

  • Access to millions of court opinions and legal decisions

  • Federal and state court coverage

  • Real-time updates from court systems

• Full Text Content:

  • Complete opinion text for citation verification

  • Structured legal document organization

  • Rich metadata including judges, courts, and dates

• Regulatory Research:

  • Search and retrieve current federal regulations

  • Validate regulatory citations and references

• Legal Research:

  • Search by judge, court, case name, or content

  • Verify exact legal language and precedents

  • Validate legal citations and references

🛠️ Available MCP Tools

The CourtListener MCP Server provides these production-ready tools (see app/README.md for full details and parameters):

• Opinion & Case Search:

  • search_opinions — Search legal opinions and court decisions

  • search_dockets — Search court cases and dockets

  • search_dockets_with_documents — Search dockets with nested documents

  • search_recap_documents — Search RECAP filing documents

  • search_audio — Search oral argument audio

  • search_people — Search judges and legal professionals

• Entity Retrieval:

  • get_opinion, get_docket, get_audio, get_court, get_person, get_cluster

• Citation & Regulation Tools:

  • lookup_citation, batch_lookup_citations, verify_citation_format, parse_citation_with_citeurl, extract_citations_from_text, enhanced_citation_lookup

  • list_titles, list_agencies, search_regulations, list_all_corrections, list_corrections_by_title, get_search_suggestions, get_search_summary, get_title_search_counts, get_daily_search_counts, get_ancestry, get_title_structure, get_source_xml, get_source_json

• System & Health:

  • status, get_api_status, health_check

See app/README.md for a full reference of all tools, parameters, and usage examples.

📦 Installation

Prerequisites

• Python 3.12+

• uv for dependency management

• Internet connection for CourtListener API access

Install with uv

# Clone the repository
 git clone <repository-url>
 cd CourtListener

# Install dependencies
 uv sync

# Activate the environment (optional)
 uv shell

Environment Configuration

Create a .env file in the project root:

COURTLISTENER_BASE_URL=https://www.courtlistener.com/api/rest/v4/
COURT_LISTENER_TIMEOUT=30
LOG_LEVEL=INFO
RATE_LIMIT_REQUESTS=10
RATE_LIMIT_PERIOD=60
DEBUG=false
MCP_PORT=8765
MCP_DEV_PORT=8766

Running the Server

The server now runs with streamable-http transport by default:

uv run python -m app.server

This will start the server at:

• Host: 0.0.0.0 (accessible from external connections)

• Port: 8000

• Endpoint: http://localhost:8000/mcp/

Or use the VS Code task: Run MCP Server

Connecting to the Server

When using the streamable-http transport, clients can connect to the server using:

from fastmcp import Client

async with Client("http://localhost:8000/mcp/") as client:
    result = await client.call_tool("status")
    print(result)

💡 Usage Examples

See app/README.md for detailed tool usage and examples, including search, citation, and regulatory queries.

🐳 Docker Setup

# Production
 docker-compose up -d
# Development with hot reload
 docker-compose --profile dev up --build

🧪 Testing

uv run pytest
uv run pytest --cov=app --cov-report=term-missing

See tests/README.md for test suite details, coverage, and troubleshooting.

🔧 Development

uv run ruff format .
uv run ruff check .
uv run mypy app/
uv run pip-audit

🚨 Troubleshooting

See app/README.md and tests/README.md for troubleshooting and advanced usage.

📚 Documentation

• Source Code Documentation

• Test Documentation

• Project Context

• CourtListener API Documentation

• eCFR API Documentation

• FastMCP Framework

• Model Context Protocol

Ready to use! The CourtListener MCP Server provides production-ready access to federal regulations and legal data through 20+ comprehensive MCP tools.