Beliq

An MCP server for beliq, the EU e-invoicing compliance API. It lets MCP clients (Claude Desktop, Claude Code, Cursor, and others) validate, parse, generate, and convert electronic invoices (XRechnung, ZUGFeRD, Factur-X, Peppol BIS, and other UBL/CII documents) against authority-pinned, drift-checked rules, and explain exactly what fails.

beliq produces and checks the compliant document. Transmission (Peppol, PDP, KSeF, SDI), archiving, and tax-authority reporting stay with your access point.

Tools

• beliq_validate_einvoice - validate a UBL/CII XML invoice (inline or by file path) or a Factur-X/ZUGFeRD PDF (by file path). Returns the verdict, the detected format and profile, the ruleset (Schematron) version it was checked against, and every error and warning with its rule id, severity, location, and message.
• beliq_parse_einvoice - parse a UBL/CII XML invoice or a Factur-X/ZUGFeRD PDF into a structured EN 16931 invoice (number, dates, currency, seller, buyer, lines, totals). Returns the detected format and profile and the extracted invoice.
• beliq_generate_einvoice - generate a compliant document (XRechnung, ZUGFeRD, Factur-X, or Peppol BIS) from an EN 16931 invoice object. XML comes back inline; a PDF is written to the outputPath you give. Validates the result before returning by default (verify), so a non-compliant document fails rather than coming back.
• beliq_convert_einvoice - convert a document from one EN 16931 format to another (targetFormat of cii, ubl, xrechnung, peppol-bis, facturx, or zugferd). An XML target comes back inline; a PDF target is written to outputPath. Reports any elements the conversion could not carry across.
• beliq_check_account - verify the configured API key and report the plan and remaining quota. Calls GET /v1/me, which draws no quota; useful as a connection and credential smoke test.

Installation

Requires Node.js >= 20.15. Published to npm, so clients can run it with npx:

npx -y beliq-mcp

The server is configured entirely through environment variables (see below).

Configuration

Variable	Required	Default	Description
BELIQ_API_KEY	yes	-	API key from the beliq dashboard (API Keys).
BELIQ_AUTH	no	header	How the key is sent: header (X-API-Key) or bearer (Authorization: Bearer).
BELIQ_BASE_URL	no	https://api.beliq.eu	Override for a self-hosted deployment; defaults to the production API.

Client setup

Claude Code

claude mcp add beliq -e BELIQ_API_KEY=your-key -- npx -y beliq-mcp

Claude Desktop

Add to claude_desktop_config.json (Settings > Developer > Edit Config):

{
  "mcpServers": {
    "beliq": {
      "command": "npx",
      "args": ["-y", "beliq-mcp"],
      "env": {
        "BELIQ_API_KEY": "your-key"
      }
    }
  }
}

Cursor

Add to ~/.cursor/mcp.json (or a project .cursor/mcp.json) using the same mcpServers block shown for Claude Desktop.

Reading a result

beliq_validate_einvoice returns a short text verdict plus a structured result:

• valid is true only when there are no errors; warnings do not make a document invalid.
• format and profileDetected report the detected syntax and business profile.
• schematronVersion is the exact ruleset revision the check ran against.
• errors[] and warnings[] each carry ruleId, severity, location (an XPath when available), and message.

beliq_parse_einvoice returns the detected format and profileDetected plus the extracted invoice object (EN 16931 fields: number, dates, currency, seller, buyer, lines, totals, and any national extensions present).

beliq_generate_einvoice returns the output kind (xml or pdf), the contentType, and the schematronVersion the document was checked against. An XML document is also returned inline as xml; a PDF (and an XML when you set outputPath) is written to disk, and the call reports outputPath and bytesWritten. It does not overwrite an existing file: pick a path that does not exist.

beliq_convert_einvoice returns the output kind, the resolved sourceFormat and targetFormat, and lostElementsCount/lostElements for anything the conversion could not carry across. An XML target comes back inline as xml; a PDF target (facturx / zugferd) is written to outputPath. Like generate, it never overwrites an existing file.

A PDF (Factur-X / ZUGFeRD) must be passed by documentPath for validate, parse, and convert, not inlined as text.

Agent skill

skill/SKILL.md is a portable agent skill that teaches a model when to validate, how to read errors/warnings, and how to report a verdict, using the tools above. Drop it into a skills directory for an agent that should validate invoices on request.

Development

This server depends on the published @beliq/sdk, which carries the request, transport, and result-shaping logic. No lockfile is committed; @beliq/sdk is resolved fresh at install time.

• npm install
• npm run build - compile to dist/
• npm run typecheck
• npm run lint
• npm test - unit tests (result summary) and an in-memory MCP round-trip with a fake SDK client
• BELIQ_API_KEY=your-key npm run test:integration - live smoke tests against the real API
• npm run scrub:check - check for em-dashes in source and docs

Run the built server directly for a quick check:

BELIQ_API_KEY=your-key node dist/index.js

License

MIT