folio-mcp

MCP server for FOLIO, the Federated Open Legal Information Ontology.

FOLIO is an open-source legal ontology with 18,000+ concepts covering areas of law, document types, legal entities, governmental bodies, and more. This MCP server makes the full ontology available to AI agents as searchable, browsable tools.

A public REST API is already available at https://folio.openlegalstandard.org/ with interactive Swagger documentation at /docs. This MCP server wraps the same ontology for native use in AI coding assistants and agent frameworks.

License: MIT (server code) / CC-BY 4.0 (ontology data)

Backends

folio-mcp supports two interchangeable backends:

API mode (default)

The server starts instantly and delegates all queries to the public API at https://folio.openlegalstandard.org/. No local ontology loading required.

Local mode

Loads the full FOLIO ontology in-process (~18k classes). Useful for offline work or when embedded in folio-api.

# Install with local dependencies
pip install folio-mcp[local]

# Run in local mode
folio-mcp --local

# Or via environment variable
FOLIO_MCP_LOCAL=1 folio-mcp

Custom API URL

Point to a different FOLIO API instance:

folio-mcp --api-url https://my-folio-instance.example.com

Installation

Claude Code

claude mcp add folio -- uvx folio-mcp

Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "folio": {
      "command": "uvx",
      "args": ["folio-mcp"]
    }
  }
}

Cursor

Add to .cursor/mcp.json in your project:

{
  "mcpServers": {
    "folio": {
      "command": "uvx",
      "args": ["folio-mcp"]
    }
  }
}

VS Code

Add to your User Settings (JSON):

{
  "mcp": {
    "servers": {
      "folio": {
        "command": "uvx",
        "args": ["folio-mcp"]
      }
    }
  }
}

Remote (Streamable HTTP)

Connect to the hosted endpoint:

https://folio.openlegalstandard.org/mcp

Manual (pip)

pip install folio-mcp
folio-mcp

Tools (12)

Browse operations return compact summaries (iri, label, definition). Use get_concept(iri) for full details including translations (31% of concepts, 10+ languages), preferred labels, external identifiers, and cross-references.

Prompts (3)

Each prompt guides the LLM through the correct tool workflow and returns structured output (FOLIO label, IRI, definition, confidence, reasoning).

Resources (3)

Taxonomy Branches

The FOLIO ontology is organized into 24 top-level branches:

Development

# Clone and install
git clone https://github.com/alea-institute/folio-mcp.git
cd folio-mcp
uv sync

# Run tests (requires folio-python for local backend tests)
uv sync --extra local
uv run pytest tests/

# Run with MCP Inspector
uv run mcp dev folio_mcp/server.py

# Run locally for Claude Code
claude mcp add folio-dev -- uv run --directory /path/to/folio-mcp folio-mcp

Links

• FOLIO Website
• FOLIO REST API — public API for direct HTTP access
• FOLIO API Docs (Swagger) — interactive API documentation
• folio-python — Python client library
• folio-api — REST API server
• ALEA Institute