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einvoice-mcp

by makririch

E-Invoice MCP Server

MCP Server fuer E-Rechnungen im DACH-Raum — XRechnung erstellen, validieren und Daten extrahieren. Direkt aus Claude, Cursor oder jedem MCP-Client.

npm version License: MIT

Was ist das?

E-Invoice MCP ist ein Model Context Protocol Server fuer die Erstellung und Validierung von E-Rechnungen nach dem deutschen XRechnung-Standard. Ab 2027 muessen alle Unternehmen in Deutschland E-Rechnungen versenden koennen — mit diesem Tool bist du vorbereitet.

Du sagst Claude einfach: "Erstelle eine Rechnung an die Beispiel GmbH fuer 10 Stunden Beratung" — und erhaeltst eine valide XRechnung als UBL 2.1 XML.

Related MCP server: mcp-einvoicing-de

Features

  • XRechnung erstellen — Valides UBL 2.1 XML aus strukturierten Daten (EN 16931 + XRechnung 3.0.2)

  • E-Rechnung validieren — Syntax, Pflichtfelder und deutsche Business-Regeln (BR-DE) pruefen

  • Daten extrahieren — Strukturierte Daten aus UBL- oder CII-XML lesen

  • Format-Info — Nachschlagewerk fuer Pflichtfelder, Steuer-Kategorien, Einheiten-Codes und Fristen

  • Automatische Berechnung — Netto, Brutto, Steuerbetraege werden automatisch berechnet

  • Plugin-faehig — Kann standalone laufen ODER in den BuchPilot MCP Server integriert werden

  • Keine externen Dienste — Alles laeuft lokal, keine API-Keys noetig

  • Keine nativen Abhaengigkeiten — Laeuft auf jedem System mit Node.js

Gesetzliche Fristen

Datum

Was passiert

01.01.2025

Alle Unternehmen muessen E-Rechnungen empfangen koennen

31.12.2026

PDF-Rechnungen nur noch mit Empfaenger-Zustimmung erlaubt

01.01.2027

Unternehmen >800.000 EUR Umsatz muessen E-Rechnungen senden

01.01.2028

ALLE Unternehmen muessen E-Rechnungen senden

Fehlerhafte E-Rechnungen koennen zum Verlust des Vorsteuerabzugs fuehren (+ 6% Verzinsung).

Installation

Voraussetzungen

  • Node.js >= 18

npm (global)

npm install -g einvoice-mcp

Von Source

git clone https://github.com/makririch/einvoice-mcp.git
cd einvoice-mcp
npm install
npm run build

Konfiguration

Dieser MCP Server benoetigt keine Konfiguration. Es werden keine API-Keys oder externe Dienste benoetigt — alles laeuft lokal.

Nutzung

Server starten (standalone)

# Nach npm install -g:
einvoice-mcp

# Oder von Source:
npm start

# Entwicklung mit Auto-Reload:
npm run dev

Der Server laeuft ueber stdio und wartet auf MCP-Nachrichten.

In Claude Desktop verwenden

Siehe Claude Desktop Setup Guide fuer eine detaillierte Anleitung.

Kurzversion — fuege in claude_desktop_config.json hinzu:

{
  "mcpServers": {
    "einvoice": {
      "command": "npx",
      "args": ["-y", "einvoice-mcp"]
    }
  }
}

Beispiele (natuerliche Sprache in Claude)

Nachdem du den Server konfiguriert hast, kannst du Claude z.B. fragen:

  • "Erstelle eine XRechnung an die Beispiel GmbH fuer 10 Stunden Beratung zu 150 EUR"

  • "Ist diese XML-Datei eine gueltige XRechnung?"

  • "Extrahiere die Rechnungsdaten aus diesem XML"

  • "Welche Pflichtfelder brauche ich fuer eine XRechnung?"

  • "Welche Steuer-Kategorien gibt es und was bedeuten sie?"

  • "Bis wann muss mein Unternehmen E-Rechnungen versenden koennen?"

Quickstart

Eine Schritt-fuer-Schritt-Anleitung "Erstelle deine erste XRechnung in 5 Minuten" findest du in docs/quickstart.md.

Tool-Referenz

Eine vollstaendige Referenz aller 4 Tools mit Parametern, Beispiel-Inputs und Beispiel-Outputs findest du in docs/tool-reference.md.

Kurzuebersicht

Tool

Beschreibung

create_xrechnung

XRechnung (UBL 2.1 XML) aus strukturierten Daten erstellen

validate_invoice

E-Rechnung XML validieren (Syntax + BR-DE Business-Regeln)

extract_data

Strukturierte Daten aus UBL- oder CII-XML extrahieren

get_format_info

Nachschlagewerk fuer Formate, Pflichtfelder, Codes und Fristen

BuchPilot-Integration

E-Invoice MCP kann als Plugin in den BuchPilot MCP Server integriert werden:

import { registerEInvoiceTools } from "einvoice-mcp";
registerEInvoiceTools(server);

Kombination: BuchPilot erstellt eine Rechnung in Lexoffice -> Daten extrahieren -> XRechnung erzeugen -> fertige E-Rechnung.

Unterstuetzte Standards

Standard

Version

Status

XRechnung

3.0.2

Erstellen + Validieren

EN 16931

—

Basis fuer XRechnung

UBL 2.1

—

XML-Syntax fuer XRechnung

CII (Cross Industry Invoice)

—

Extrahieren (Lesen)

ZUGFeRD / Factur-X

2.3

Extrahieren (Lesen), Erstellen geplant

FAQ / Troubleshooting

"XML konnte nicht geparst werden"

  • Ist das XML well-formed? (Alle Tags korrekt geschlossen?)

  • Ist es tatsaechlich eine UBL- oder CII-Rechnung? (Root-Element muss <Invoice> oder <CrossIndustryInvoice> sein)

  • Ist das Encoding UTF-8?

Validierung zeigt Fehler "BR-DE-13: Buyer Reference ist Pflicht"

Die Kaeufer-Referenz (BT-10) ist in XRechnung Pflicht. Bei Rechnungen an oeffentliche Auftraggeber ist das die Leitweg-ID. Bei B2B-Rechnungen kann es eine beliebige Referenz sein (z.B. Bestellnummer).

{
  "buyerReference": "04011000-12345-67"
}

Validierung zeigt Warnung "BR-DE-21: Telefonnummer empfohlen"

Das ist nur eine Warnung, kein Fehler. Die Rechnung ist trotzdem gueltig. Fuer beste Kompatibilitaet solltest du aber eine Telefonnummer des Verkaeufers angeben.

Welche Steuer-Kategorien gibt es?

Code

Name

Beschreibung

Steuersaetze

S

Standard

Normaler Steuersatz

19%, 7%

Z

Nullsatz

0% (z.B. innergemeinschaftlich mit USt-Befreiung)

0%

E

Steuerbefreit

z.B. Kleinunternehmer nach Paragraph 19 UStG

0%

AE

Reverse Charge

Steuerschuldnerschaft des Empfaengers (Paragraph 13b UStG)

0%

K

Innergemeinschaftlich

Steuerfreie innergemeinschaftliche Lieferung

0%

Welche Einheiten-Codes gibt es?

Code

Name

Beschreibung

H87

Stueck

Einzelne Einheit (Default)

HUR

Stunde

Arbeitsstunde

DAY

Tag

Arbeitstag

MON

Monat

Kalendermonat

KGM

Kilogramm

Gewicht

MTR

Meter

Laenge

LTR

Liter

Volumen

MTK

Quadratmeter

Flaeche

SET

Set/Paket

Zusammenstellung

C62

Einheit (generisch)

Allgemeine Mengeneinheit

Server startet, aber Claude erkennt die Tools nicht

  • Pruefe ob die claude_desktop_config.json korrekt ist

  • Starte Claude Desktop neu nach Konfigurationsaenderungen

  • Pruefe die Logs: ~/Library/Logs/Claude/mcp.log (macOS)

Lizenz

MIT — Frei nutzbar, auch kommerziell.

Autor

MaKri — GitHub

Available Tools

6 tools
convert_formatA

Konvertiert E-Rechnungen zwischen UBL (XRechnung), CII (ZUGFeRD) und JSON. Converts e-invoices between formats: ubl_to_cii, cii_to_ubl, ubl_to_json, cii_to_json, json_to_ubl, json_to_cii.

ParametersJSON Schema
NameRequiredDescriptionDefault
directionYesKonvertierungsrichtung
inputYesInput-Daten: XML-String fuer ubl/cii, JSON-String fuer json
validate_outputNoOutput nach Konvertierung validieren (nur fuer XML-Output)

TDQS

A3.6/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden but provides minimal behavioral information. It mentions what formats can be converted but doesn't disclose important traits like whether this is a read-only operation, potential side effects, error handling, performance characteristics, or authentication requirements. The description doesn't contradict annotations (none exist), but fails to provide adequate behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise with zero wasted words. It's front-loaded with the core purpose in the first sentence, followed by specific conversion directions. The bilingual presentation (German/English) is efficient for clarity. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (format conversion with multiple directions), no annotations, and no output schema, the description is insufficient. It doesn't explain what the tool returns, error conditions, input format requirements beyond basic mentions, or how validation works. For a data transformation tool with 3 parameters, this leaves significant gaps in understanding.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema description coverage, the baseline is 3. The description adds some value by listing all six conversion directions, which helps understand the 'direction' parameter's enum values, but doesn't provide additional semantic context beyond what's already in the schema descriptions for 'input' and 'validate_output' parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with specific verbs ('konvertiert', 'converts') and resources ('E-Rechnungen', 'e-invoices'), and explicitly lists all six conversion directions. It distinguishes itself from sibling tools by focusing on format conversion rather than creation, extraction, validation, or information retrieval.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context about when to use this tool (converting between UBL, CII, and JSON formats), but doesn't explicitly state when NOT to use it or mention alternatives. It doesn't compare with sibling tools like 'get_format_info' or 'validate_invoice' that might be relevant in some scenarios.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

create_xrechnungC

Erstellt eine XRechnung (UBL 2.1 XML) aus strukturierten Daten. Konform zu EN 16931 + XRechnung 3.0.2. Creates a valid XRechnung XML from structured data.

ParametersJSON Schema
NameRequiredDescriptionDefault
invoiceNumberYesRechnungsnummer (eindeutig)
issueDateYesRechnungsdatum (YYYY-MM-DD)
dueDateNoFaelligkeitsdatum (YYYY-MM-DD)
paymentTermsNoZahlungsbedingungen (z.B. 'Zahlbar innerhalb von 30 Tagen')
sellerYesRechnungssteller
buyerYesRechnungsempfaenger
lineItemsYesRechnungspositionen
currencyNoWaehrung (ISO 4217)EUR
paymentMeansCodeNoZahlungsart: 30=Ueberweisung, 58=SEPA-Ueberweisung, 59=SEPA-Lastschrift58
ibanNoIBAN fuer Zahlung
bicNoBIC
bankNameNoName der Bank
buyerReferenceNoLeitweg-ID oder Kaeufer-Referenz (BT-10, Pflicht in XRechnung)
orderReferenceNoBestellnummer des Kaeufers (BT-13)
noteNoFreitext-Bemerkung

TDQS

C2.9/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It states the tool creates a valid XRechnung XML, implying a write operation, but doesn't disclose behavioral traits such as error handling, validation steps, or output format details. This is inadequate for a complex tool with 15 parameters.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise and front-loaded, stating the core purpose in one bilingual sentence. It avoids redundancy and wastes no words, though it could be slightly more structured by separating key points.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex tool with 15 parameters, nested objects, and no annotations or output schema, the description is incomplete. It lacks details on behavioral aspects, error handling, and output expectations, leaving gaps that could hinder effective tool selection and invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters thoroughly. The description adds no additional parameter semantics beyond what the schema provides, such as explaining relationships between fields or usage examples. Baseline 3 is appropriate when schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool creates an XRechnung XML from structured data, specifying the format (UBL 2.1) and standards (EN 16931 + XRechnung 3.0.2). It distinguishes from siblings like 'create_zugferd' by focusing on XRechnung, though it doesn't explicitly compare them.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit guidance on when to use this tool versus alternatives like 'create_zugferd' or 'convert_format'. The description mentions conformance to specific standards, which implies usage for XRechnung-compliant invoices, but lacks clear when/when-not scenarios or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

create_zugferdB

Erstellt ZUGFeRD 2.3 CII XML (Factur-X). Returns CII XML for embedding into PDF/A-3. Creates ZUGFeRD-compatible e-invoice XML in CII format.

ParametersJSON Schema
NameRequiredDescriptionDefault
invoiceNumberYesRechnungsnummer (eindeutig)
issueDateYesRechnungsdatum (YYYY-MM-DD)
dueDateNoFaelligkeitsdatum (YYYY-MM-DD)
paymentTermsNoZahlungsbedingungen
sellerYesRechnungssteller
buyerYesRechnungsempfaenger
lineItemsYesRechnungspositionen
currencyNoWaehrung (ISO 4217)EUR
ibanNoIBAN fuer Zahlung
bicNoBIC
buyerReferenceNoLeitweg-ID / Kaeufer-Referenz (BT-10)
orderReferenceNoBestellnummer des Kaeufers (BT-13)
noteNoFreitext-Bemerkung

TDQS

B3.1/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden for behavioral disclosure. While it states the tool creates XML for embedding into PDF/A-3, it doesn't mention whether this is a pure generation tool (no side effects), what permissions might be needed, error handling, or performance characteristics. The description is minimal and lacks important behavioral context for a creation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is efficiently structured in two sentences that convey the core functionality and output format. While it could be slightly more detailed about behavioral aspects, there's no wasted language or redundancy. The information is front-loaded with the primary purpose stated immediately.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex invoice creation tool with 13 parameters, nested objects, and no output schema or annotations, the description is insufficient. It doesn't explain what the tool returns (beyond mentioning 'CII XML'), error conditions, validation performed, or how the generated XML should be used with PDF/A-3. The agent lacks crucial context for proper tool invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, providing comprehensive parameter documentation. The description adds no parameter-specific information beyond what's in the schema. According to scoring rules, when schema coverage is high (>80%), the baseline is 3 even with no param info in the description, which applies here.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with specific verbs ('Erstellt', 'Creates') and resources ('ZUGFeRD 2.3 CII XML', 'Factur-X', 'e-invoice XML'), and distinguishes it from siblings by specifying the exact format (ZUGFeRD 2.3 CII) and use case (embedding into PDF/A-3). It explicitly mentions the output format and application context.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives like 'create_xrechnung' or 'convert_format'. It doesn't mention prerequisites, constraints, or typical scenarios for choosing ZUGFeRD over other invoice formats, leaving the agent without contextual usage information.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

extract_dataC

Extrahiert strukturierte Daten aus einer E-Rechnung (UBL-XML oder CII-XML). Extracts structured data from an e-invoice XML.

ParametersJSON Schema
NameRequiredDescriptionDefault
xmlNoE-Rechnung XML als String
base64NoBase64-kodierte XML-Datei

TDQS

C2.9/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool extracts data but doesn't describe what happens if the XML is invalid, what structured data is returned (e.g., fields like invoice number, date), or any performance or error-handling traits. This is inadequate for a tool that processes XML input without output schema details.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is brief and front-loaded, with the core purpose stated first in both German and English. The bilingual repetition is slightly redundant but doesn't significantly detract from efficiency. It avoids unnecessary elaboration, making it easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (processing XML for data extraction), lack of annotations, and no output schema, the description is incomplete. It doesn't explain what structured data is extracted, how errors are handled, or the format of the output, leaving critical gaps for the agent to understand the tool's behavior and results.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema description coverage is 100%, so the schema already documents both parameters ('xml' as a string and 'base64' as a Base64-encoded XML file). The description adds no additional meaning beyond implying these are alternative input methods for e-invoice XML, which is already clear from the schema. This meets the baseline for high schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'Extracts structured data from an e-invoice XML.' It specifies the verb ('extracts'), resource ('structured data'), and source format ('e-invoice XML'), though it doesn't explicitly differentiate from sibling tools like 'validate_invoice' or 'convert_format'. The bilingual phrasing adds clarity but doesn't enhance differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. It mentions the input formats (UBL-XML or CII-XML) but doesn't specify scenarios where extraction is needed over validation or conversion, nor does it mention prerequisites or exclusions. This leaves the agent with minimal context for tool selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_format_infoB

Gibt Informationen ueber E-Rechnungs-Formate, Pflichtfelder, Steuer-Kategorien, Einheiten-Codes und gesetzliche Fristen zurueck. Useful reference for creating valid invoices.

ParametersJSON Schema
NameRequiredDescriptionDefault
formatNoWelches Format abfragenall
topicNooverview=Formatbeschreibung, required_fields=Pflichtfelder, tax_categories=USt-Kategorien, unit_codes=Einheiten, deadlines=Fristenoverview

TDQS

B3.2/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool returns information, implying it's a read-only operation, but doesn't mention potential side effects, error handling, rate limits, or authentication needs. This is a significant gap for a tool with no annotation coverage.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise and front-loaded, with two sentences that efficiently convey the tool's purpose and utility. The first sentence lists the key information returned, and the second clarifies its use case. There's no unnecessary repetition or fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (2 parameters with enums) and lack of annotations and output schema, the description is somewhat complete but has gaps. It covers the purpose and general use case but omits behavioral details like response format, error conditions, or how the returned information is structured, which is important for a reference tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema description coverage is 100%, with clear enum descriptions for both parameters. The description adds minimal value beyond the schema by listing topics like 'required_fields' and 'tax_categories', but doesn't provide additional context on parameter interactions or usage examples. Baseline 3 is appropriate given the high schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: it returns information about e-invoicing formats, required fields, tax categories, unit codes, and legal deadlines. It specifies the resource (e-invoicing formats) and the type of information returned, though it doesn't explicitly differentiate from sibling tools like 'validate_invoice' or 'extract_data' beyond being a reference tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage as a reference for creating valid invoices, suggesting it should be used when needing format details. However, it lacks explicit guidance on when to use this tool versus alternatives like 'validate_invoice' or 'create_xrechnung', and doesn't specify prerequisites or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

validate_invoiceC

Prueft ob XML eine gueltige E-Rechnung (XRechnung/ZUGFeRD) ist. Validiert Syntax, Pflichtfelder und deutsche Business-Regeln (BR-DE). Validates e-invoice XML.

ParametersJSON Schema
NameRequiredDescriptionDefault
xmlNoE-Rechnung XML als String
base64NoBase64-kodierte XML-Datei
levelNoValidierungstiefe: syntax=well-formed, schema=Struktur, full=inkl. BR-DE-Regelnfull

TDQS

C2.9/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions validation actions but lacks details on permissions, rate limits, error handling, or output format. For a validation tool with zero annotation coverage, this is insufficient, as it doesn't describe what happens during or after validation beyond the basic purpose.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise and front-loaded, stating the core purpose in the first sentence and adding a brief English translation. Both sentences earn their place by clarifying the tool's function, though it could be slightly more structured to highlight key aspects like validation levels. No wasted words, but minor improvements in organization are possible.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (3 parameters, no output schema, no annotations), the description is minimally adequate. It covers the purpose but lacks context on usage, behavioral traits, and output expectations. With 100% schema coverage, it compensates partially, but for a validation tool without annotations or output schema, more completeness is needed to guide an AI agent effectively.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters (xml, base64, level) with descriptions and enum values. The description adds no additional parameter semantics beyond what the schema provides, such as explaining trade-offs between 'xml' and 'base64' inputs or elaborating on 'level' choices. Baseline 3 is appropriate as the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: validating e-invoice XML against XRechnung/ZUGFeRD standards with syntax, mandatory fields, and German business rules. It uses specific verbs ('prüft', 'validates') and identifies the resource (XML). However, it doesn't explicitly differentiate from sibling tools like 'get_format_info' or 'extract_data', which might also involve XML inspection.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'create_xrechnung' or 'convert_format', nor does it specify prerequisites or contexts for validation. Usage is implied but not explicitly stated, leaving gaps for an AI agent to determine appropriateness.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

  1. 6 tool updatesv0.1.2
    • First observedconvert_format
    • First observedcreate_xrechnung
    • First observedcreate_zugferd
    • First observedextract_data
    • First observedget_format_info
    • First observedvalidate_invoice

TDQS

A3.5/5.0

Scored across 6 tools

Disambiguation5/5

Each tool has a clearly distinct purpose with no overlap: convert_format handles format conversion, create_xrechnung and create_zugferd create specific invoice types, extract_data extracts data from invoices, get_format_info provides reference information, and validate_invoice validates invoices. The descriptions reinforce these distinct roles, making tool selection unambiguous.

Naming Consistency5/5

All tool names follow a consistent verb_noun pattern using snake_case: convert_format, create_xrechnung, create_zugferd, extract_data, get_format_info, and validate_invoice. This uniformity makes the tool set predictable and easy to navigate for an agent.

Tool Count5/5

With 6 tools, the server is well-scoped for e-invoice processing, covering creation, conversion, validation, data extraction, and reference information. Each tool earns its place without bloat, fitting typical expectations for a domain-specific server.

Completeness4/5

The tool set provides strong coverage for e-invoice workflows, including creation (XRechnung and ZUGFeRD), conversion between formats, validation, data extraction, and reference info. A minor gap is the lack of update or delete operations for invoices, but this is reasonable as invoices are typically immutable once created, and agents can work around this by recreating or modifying data externally.

Maintenance

ActivityInactive
ResponsivenessNo issues

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