GLEIF MCP Server

A Model Context Protocol (MCP) server for accessing the Global Legal Entity Identifier (LEI) database via GLEIF's public API.

What this does: Gives your AI assistant the ability to look up company identities, verify legal entities, and explore corporate ownership structures using the official GLEIF database. Works with Claude Desktop, Claude Code, Cursor, VS Code, Windsurf, and other MCP-compatible tools. Ask questions in plain English; get structured answers instantly.

Use Cases

• KYC & Onboarding: Verify counterparty identities before signing contracts
• Compliance Checks: Validate LEIs for MiFID II, EMIR, or DORA reporting
• Due Diligence: Research corporate ownership chains and ultimate parents
• Financial Analysis: Cross-reference securities (ISIN) and banks (BIC/SWIFT) with their legal entities
• Data Enrichment: Batch-process company lists to add LEI data

What is LEI?

The Legal Entity Identifier (LEI) is a 20-character alphanumeric code that uniquely identifies legal entities participating in financial transactions worldwide. It's mandated by 200+ regulations including MiFID II, EMIR, Dodd-Frank, and DORA.

LEI Format (ISO 17442):

• Characters 1-4: LOU (Local Operating Unit) prefix
• Characters 5-18: Entity-specific identifier
• Characters 19-20: Check digits (mod 97 validation)

Example: HWUPKR0MPOU8FGXBT394 (Apple Inc.)

Features

Core Capabilities

• LEI Lookup: Get full entity details by LEI code
• Batch Lookup: Look up multiple LEIs in a single request (up to 100)
• Entity Search: Find companies by name with fuzzy matching and pagination
• LEI Validation: Verify format, check digits (ISO 17442), and registration status

Financial Identifiers

• BIC/SWIFT Lookup: Find bank LEIs from BIC codes
• ISIN Lookup: Find security issuer LEIs from ISIN codes
• Country Browse: List entities by jurisdiction

Relationships & Compliance

• Corporate Ownership: Parent companies, subsidiaries, ultimate parents
• Fund Relationships: Fund managers, umbrella funds, sub-funds
• Reporting Exceptions: Level 2 data exceptions with reasons
• LEI Issuers: List and details of all Local Operating Units (LOUs)

Performance & Reliability

• Fast Responses: Results are cached locally, so repeat queries return instantly
• No API Key Needed: Works out of the box with GLEIF's public API
• Handles Errors Gracefully: Automatic retries on timeouts or temporary failures
• Stays Within Limits: Built-in rate limiting prevents hitting GLEIF's quotas

Installation

Download Binary

Pre-built binaries for all platforms on the releases page:

# macOS/Linux - download and make executable
chmod +x gleif-mcp-server-darwin-arm64

Build from Source

Requires Go 1.25+:

git clone https://github.com/olgasafonova/gleif-mcp-server.git
cd gleif-mcp-server
go build -o gleif-mcp-server .

Install via Go

go install github.com/olgasafonova/gleif-mcp-server@latest

AI Agent Setup

Quickest start: Using Claude Desktop? Just add the config below and restart. Using an IDE like Cursor? Same idea, different config file. Pick your tool below.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "gleif": {
      "command": "/path/to/gleif-mcp-server"
    }
  }
}

Restart Claude Desktop after editing the config.

Claude Code (CLI)

# Add the server
claude mcp add gleif /path/to/gleif-mcp-server

# Or with scope for all projects
claude mcp add --scope user gleif /path/to/gleif-mcp-server

Cursor IDE

Add to .cursor/mcp.json in your project or ~/.cursor/mcp.json for global config:

{
  "mcpServers": {
    "gleif": {
      "command": "/path/to/gleif-mcp-server"
    }
  }
}

VS Code with Continue Extension

Add to .continue/config.json:

{
  "experimental": {
    "modelContextProtocolServers": [
      {
        "name": "gleif",
        "transport": {
          "type": "stdio",
          "command": "/path/to/gleif-mcp-server"
        }
      }
    ]
  }
}

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "gleif": {
      "command": "/path/to/gleif-mcp-server"
    }
  }
}

Cline (VS Code Extension)

Add via Cline's MCP settings or in .vscode/cline_mcp_settings.json:

{
  "mcpServers": {
    "gleif": {
      "command": "/path/to/gleif-mcp-server",
      "args": []
    }
  }
}

Tools Reference

Core Lookup Tools

Search Tools

Relationship Tools

LEI Issuer Tools

Compliance Tools

Usage Examples

Basic LEI Lookup

Prompt: "Look up LEI HWUPKR0MPOU8FGXBT394"

Returns: Full entity details for Apple Inc. including legal name, headquarters address, jurisdiction (US-CA), entity status, registration status, managing LOU, and next renewal date.

Company Search with Pagination

Prompt: "Search for Deutsche Bank, show page 2"

Tool call:

{
  "name": "search_entity",
  "arguments": {
    "query": "Deutsche Bank",
    "limit": 20,
    "page": 2,
    "fuzzy": true
  }
}

Returns: List of matching entities with pagination info (total results, current page, has more).

Batch LEI Lookup

Prompt: "Look up these LEIs: HWUPKR0MPOU8FGXBT394, 5493006MHB84DD0ZWV18, 549300GKFG0RYRRQ1414"

Returns: Summary of all three entities with LEI, legal name, country, city, and status.

Find Bank by BIC

Prompt: "Find the LEI for BIC DEUTDEFF"

Returns: Deutsche Bank AG's LEI record with full details.

Find Security Issuer

Prompt: "Who issued ISIN US0378331005?"

Returns: Apple Inc. (the issuer of AAPL stock).

Corporate Structure

Prompt: "Who is the ultimate parent of this subsidiary?"

Tool call:

{
  "name": "get_relationships",
  "arguments": {
    "lei": "549300GKFG0RYRRQ1414",
    "type": "ultimate-parent"
  }
}

LEI Validation

Prompt: "Is LEI HWUPKR0MPOU8FGXBT394 valid?"

Returns:

{
  "lei": "HWUPKR0MPOU8FGXBT394",
  "valid": true,
  "status": "ISSUED",
  "entityStatus": "ACTIVE",
  "nextRenewal": "2025-08-15"
}

Check Reporting Exceptions

Prompt: "Why is parent info missing for this company?"

Tool call:

{
  "name": "get_reporting_exceptions",
  "arguments": {
    "lei": "5493006MHB84DD0ZWV18"
  }
}

Returns: Exception categories and reasons (e.g., NON_CONSOLIDATING, NATURAL_PERSONS).

List All LEI Issuers

Prompt: "Show me all LEI issuers"

Returns: Complete list of LOUs (Local Operating Units) with name, country, status, and number of sponsored LEIs.

Response Format

All tools return JSON with relevant fields. Example entity record:

{
  "lei": "HWUPKR0MPOU8FGXBT394",
  "legalName": "Apple Inc.",
  "country": "US",
  "city": "Cupertino",
  "status": "ACTIVE",
  "regStatus": "ISSUED"
}

Search results include pagination:

{
  "count": 20,
  "results": [...],
  "pagination": {
    "currentPage": 1,
    "perPage": 20,
    "total": 156,
    "lastPage": 8
  },
  "hasMore": true
}

Error Handling

The server returns structured errors:

Example error response:

{
  "code": "not_found",
  "message": "LEI not found in GLEIF database",
  "statusCode": 404,
  "retryable": false
}

Architecture

gleif-mcp-server/
├── main.go                 # Entry point, MCP server setup
├── internal/gleif/
│   ├── client.go          # GLEIF API client with caching & rate limiting
│   ├── client_test.go     # Client and validation tests
│   ├── cache.go           # LRU cache with TTL
│   ├── types.go           # Data structures for API responses
│   └── errors.go          # Structured error types
└── tools/
    ├── definitions.go     # Tool metadata and parameter specs
    ├── handlers.go        # MCP tool implementations
    └── handlers_test.go   # Handler tests with mock server

Technical Details

For developers who want the specifics:

API Reference

This server wraps the public GLEIF API:

• Base URL: https://api.gleif.org/api/v1
• Authentication: None required
• Rate Limit: 60 requests/minute
• Documentation: https://www.gleif.org/en/lei-data/gleif-api

Troubleshooting

Server won't start

• Check the binary has execute permissions: chmod +x gleif-mcp-server
• Verify the path in your MCP config is absolute, not relative

"Rate limit exceeded" errors

• The server automatically handles rate limiting with retries
• If persistent, reduce concurrent requests or wait a few minutes

"LEI not found" for valid LEI

• The GLEIF database updates daily; recently issued LEIs may not appear immediately
• Verify the LEI format (exactly 20 alphanumeric characters)

Slow responses

• First requests may be slower (cache warming)
• GLEIF API occasionally has latency spikes; retries handle this automatically

Claude Desktop doesn't show the server

• Restart Claude Desktop after editing config
• Check JSON syntax in config file
• Verify the binary path exists and is executable

Development

# Run tests
go test ./...

# Run tests with coverage
go test -coverprofile=coverage.out ./...
go tool cover -html=coverage.out

# Run tests with race detector
go test -race ./...

# Build
go build -o gleif-mcp-server .

Contributing

Contributions welcome. Please open an issue first to discuss proposed changes.

License

MIT License - see LICENSE for details.

More MCP Servers

Check out my other MCP servers:

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productplan-mcp-server	Talk to your ProductPlan roadmaps. Query OKRs, ideas, launches.

Acknowledgments

• GLEIF for the public LEI API
• Model Context Protocol for the MCP specification