mcp-einvoicing-be 🇧🇪

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Introduction

mcp-einvoicing-be is an MCP (Model Context Protocol) server that exposes tools for Belgian electronic invoicing. It covers the full Belgian e-invoicing ecosystem: Peppol BIS Billing 3.0, UBL 2.1, and the Mercurius network for public-sector invoicing. The server is part of the mcp-einvoicing-* family of country-specific servers, all built on top of mcp-einvoicing-core, which provides the shared validation engine, UBL abstractions, and Peppol network utilities.

Installation

Requirements

• Python ≥ 3.11
• mcp-einvoicing-core (installed automatically as a dependency)

Using uv (recommended)

uv add mcp-einvoicing-be

Using pip

pip install mcp-einvoicing-be

From source

git clone https://github.com/cmendezs/mcp-einvoicing-be.git
cd mcp-einvoicing-be
uv sync --all-extras

Configuration

Environment variables

The EUSR/TSR reporting and MLS tools additionally require the [xslt2] extra (pip install "mcp-einvoicing-be[xslt2]") for Schematron validation.

Claude Desktop integration

To use this server with Claude, add this configuration to your claude_desktop_config.json file:

{
  "mcpServers": {
    "einvoicing-be": {
      "command": "uvx",
      "args": ["mcp-einvoicing-be"],
      "env": {
        "BCE_API_KEY": "your-bce-api-key",
        "PEPPOL_ENV": "production"
      }
    }
  }
}

For a local development install:

{
  "mcpServers": {
    "einvoicing-be": {
      "command": "uv",
      "args": ["run", "mcp-einvoicing-be"],
      "cwd": "/path/to/mcp-einvoicing-be"
    }
  }
}

Cursor integration

Cursor supports MCP servers via stdio. Add the configuration in:

• Global (all projects): ~/.cursor/mcp.json
• Project (this repository only): .cursor/mcp.json

{
  "mcpServers": {
    "einvoicing-be": {
      "command": "uvx",
      "args": ["mcp-einvoicing-be"],
      "env": {
        "BCE_API_KEY": "your-bce-api-key",
        "PEPPOL_ENV": "production"
      }
    }
  }
}

Reload the Cursor window (Ctrl+Shift+P then Reload Window) to apply the changes.

Kiro integration

Kiro supports MCP servers via its dedicated configuration file. Two levels are available:

• Global (all projects): ~/.kiro/settings/mcp.json
• Workspace (this repository only): .kiro/settings/mcp.json

{
  "mcpServers": {
    "einvoicing-be": {
      "command": "uvx",
      "args": ["mcp-einvoicing-be"],
      "env": {
        "BCE_API_KEY": "your-bce-api-key",
        "PEPPOL_ENV": "production"
      },
      "disabled": false,
      "autoApprove": []
    }
  }
}

The file is automatically reloaded on save. You can also open the config via the command palette (Cmd+Shift+P / Ctrl+Shift+P) then MCP.

Kiro security tip: rather than writing secrets in plain text, use the syntax "BCE_API_KEY": "${BCE_API_KEY}", Kiro resolves shell environment variables at startup.

Available tools

validate_invoice_be

Validates a UBL 2.1 XML invoice. The peppol-bis-3/pint-eu profiles run real Schematron validation against the CEN EN 16931 base rules (~50 BR-* structural/arithmetic rules, via mcp-einvoicing-core's bundled base Schematron — see CHANGELOG.md v0.8.0). This does not check the Peppol-specific overlay rules (no confirmed OpenPeppol redistribution rights); results carry an explicit en16931-base-only scope warning and should not be read as full Peppol BIS3 conformance. The mercurius profile runs the Mercurius-specific overlay (endpoint scheme, PO reference) but does not check base EN 16931/Peppol BIS 3.0 compliance.

Returns a ValidationResult with valid, errors, and warnings (each carrying the failed rule ID and a human-readable message).

generate_invoice_be

Generates a valid UBL 2.1 Belgian e-invoice XML document from structured data.

The InvoiceInput object supports:

{
  "invoice_number": "INV-2024-001",
  "issue_date": "2024-01-15",
  "due_date": "2024-02-14",
  "currency_code": "EUR",
  "supplier": { "name": "...", "vat_number": "BE0428759497", "address": {...} },
  "customer": { "name": "...", "vat_number": "BE0403170701", "address": {...} },
  "lines": [{ "description": "...", "quantity": 1, "unit_price": 100.00, "vat_rate": 21.0 }]
}

Returns a UBL 2.1 XML string.

transform_to_ubl

Converts a structured JSON invoice payload to UBL 2.1 XML without full validation. Useful as a first step before validation.

lookup_vat_be

Looks up a Belgian enterprise number (VAT number) against the BCE/KBO public database.

Returns enterprise name, registered address, legal status, and NACE activity codes.

Peppol network tools

Peppol participant lookup, service-endpoint lookup, a DNS-only diagnostic, AS4 send, Peppol Directory search, and the OpenPeppol eDEC codelist tools are provided by the shared core Peppol tool plugin (mcp_einvoicing_core.peppol.tools.register_peppol_tools), mounted in server.py with a BE-specific identifier adapter: a bare Belgian VAT number (e.g. 0428759497 or BE0428759497) is normalized to the 0208:<digits> Peppol scheme (KBO/BCE enterprise number); an already scheme-qualified identifier (e.g. 0208:0428759497) passes through unchanged.

peppol_send signs outbound messages with a real wsse:Security signature as of mcp-einvoicing-core v1.20.0 (previously computed and discarded — see CHANGELOG.md v0.10.0).

See the mcp-einvoicing-core README for full parameter documentation on these tools.

Peppol reporting and status tools

Added in v0.10.0 via three opt-in core plugins, mounted unconditionally in server.py. Each raises a clear error at call time (not at registration) if its extra or data directory is missing.