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fakturai MCP server

Which servers in the official MCP registry are fakturai's own, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-26

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Whose server it is
  • Registry namede.fakturai/erechnungverified in the MCP registry

The registry name sits under fakturai.de. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-26
  • Stateanswerschecked 2026-10-26
  • Tools3
  • Server calls itselfe-rechnung
  • Server version1.27.2
  • Protocol version2025-06-18

On 2026-10-26 the server answered initialize and tools/list without a sign-in. First answer in 186 ms.

Should an agent connect itNot proven either way yet
  • Its tools do every use case we checked: Generate ZUGFeRD PDFs with embedded Factur-X XML; Validate existing e-invoices against German rules; Create test invoices before going live.
  • Checked on 1 of the 7 days it takes to judge reliability.

Once connected

  • For "Generate ZUGFeRD PDFs with embedded Factur-X XML", the likely first call is generate_einvoice.
  • For "Validate existing e-invoices against German rules", the likely first call is validate_einvoice.
  • Parameters are untyped or undescribed in 2 of 3 tools: check arguments before calling.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 1, the first on 2026-10-26
  • INITE MCP scoreafter a weeka score needs 7 daily checks: 1 so far
  • What an agent can do with it3 of 3 use cases
  • Answeredmeasuring1 of the 7 daily checks it takes to print a share
  • Median first answer530 ms
  • Space in an agent's context≈ 424 tokensthe definitions of all its tools (3), which an agent carries on every turn
  • Tool definitionsC · 72 of 100
  • Typed results3 of 3 toolsdeclared outputSchema: results come typed, read once
  • Parameters without a description: in 2 of 3
  • Not saying whether it only reads or can destroy: 3 of 3

What an agent can do with it

  • can do · Generate ZUGFeRD PDFs with embedded Factur-X XML
  • can do · Validate existing e-invoices against German rules
  • can do · Create test invoices before going live

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

None of the five warning signs in these definitions.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (30%), doing the product's job (25%), definitions (20%), context (10%) and use (15%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers3 tools · read 2026-10-26
  • generate_einvoice

    Generate a KoSIT-verified ZUGFeRD/Factur-X German e-invoice (EN 16931 / E-Rechnung). Returns pdf_b64 (base64 PDF), invoice_number, and the full validation_report. Every invoice returned has passed the official German government KoSIT…

  • validate_einvoice

    Validate an existing ZUGFeRD/Factur-X/E-Rechnung invoice. Accepts a base64-encoded PDF or raw CII XML. Runs the full three-validator check: PDF/A conformance, EN 16931 Schematron, and the official German KoSIT acceptance gate. No…

  • compliance_status

    Check the e-rechnung engine health: KoSIT + Mustang daemon status and dependency version pins vs. latest releases. Use before bulk invoice generation to confirm the compliance gate is fully operational.

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "erechnung": {
      "type": "http",
      "url": "https://fakturai.de/mcp"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http fakturai https://fakturai.de/mcp

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://fakturai.de/mcp as a custom connector in the settings.

OpenAPI spec

3 paths, read 2026-10-26. Open the spec ↗

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.