einvoice-mcp
MCP-сервер для электронных счетов (E-Invoice)
MCP-сервер для электронных счетов в регионе DACH — создание, проверка и извлечение данных XRechnung. Напрямую из Claude, Cursor или любого MCP-клиента.
Что это такое?
E-Invoice MCP — это сервер Model Context Protocol для создания и проверки электронных счетов в соответствии с немецким стандартом XRechnung. Начиная с 2027 года все компании в Германии должны уметь отправлять электронные счета — с этим инструментом вы будете готовы.
Вы просто говорите Claude: «Создай счет для Beispiel GmbH на 10 часов консультаций» — и получаете валидный XRechnung в формате UBL 2.1 XML.
Related MCP server: mcp-einvoicing-de
Функции
Создание XRechnung — валидный UBL 2.1 XML из структурированных данных (EN 16931 + XRechnung 3.0.2)
Проверка электронных счетов — проверка синтаксиса, обязательных полей и немецких бизнес-правил (BR-DE)
Извлечение данных — чтение структурированных данных из UBL- или CII-XML
Информация о форматах — справочник обязательных полей, налоговых категорий, кодов единиц измерения и сроков
Автоматический расчет — нетто, брутто и суммы налогов рассчитываются автоматически
Поддержка плагинов — может работать автономно ИЛИ быть интегрирован в MCP-сервер BuchPilot
Никаких внешних сервисов — все работает локально, API-ключи не нужны
Никаких нативных зависимостей — работает на любой системе с Node.js
Законодательные сроки
Дата | Что происходит |
01.01.2025 | Все компании должны уметь принимать электронные счета |
31.12.2026 | PDF-счета разрешены только с согласия получателя |
01.01.2027 | Компании с оборотом >800 000 евро должны отправлять электронные счета |
01.01.2028 | ВСЕ компании должны отправлять электронные счета |
Ошибочные электронные счета могут привести к потере права на вычет НДС (+ 6% годовых).
Установка
Требования
Node.js >= 18
npm (глобально)
npm install -g einvoice-mcpИз исходного кода
git clone https://github.com/makririch/einvoice-mcp.git
cd einvoice-mcp
npm install
npm run buildКонфигурация
Этому MCP-серверу не требуется конфигурация. API-ключи или внешние сервисы не нужны — все работает локально.
Использование
Запуск сервера (автономно)
# Nach npm install -g:
einvoice-mcp
# Oder von Source:
npm start
# Entwicklung mit Auto-Reload:
npm run devСервер работает через stdio и ожидает MCP-сообщения.
Использование в Claude Desktop
См. Руководство по настройке Claude Desktop для получения подробных инструкций.
Краткая версия — добавьте в claude_desktop_config.json:
{
"mcpServers": {
"einvoice": {
"command": "npx",
"args": ["-y", "einvoice-mcp"]
}
}
}Примеры (естественный язык в Claude)
После настройки сервера вы можете спросить Claude, например:
«Создай XRechnung для Beispiel GmbH на 10 часов консультаций по 150 евро»
«Является ли этот XML-файл валидным XRechnung?»
«Извлеки данные счета из этого XML»
«Какие обязательные поля нужны для XRechnung?»
«Какие существуют налоговые категории и что они означают?»
«До какого срока моя компания должна уметь отправлять электронные счета?»
Быстрый старт
Пошаговое руководство «Создай свой первый XRechnung за 5 минут» можно найти в docs/quickstart.md.
Справочник инструментов
Полный справочник всех 4 инструментов с параметрами, примерами входных и выходных данных можно найти в docs/tool-reference.md.
Краткий обзор
Инструмент | Описание |
| Создание XRechnung (UBL 2.1 XML) из структурированных данных |
| Проверка XML электронного счета (синтаксис + бизнес-правила BR-DE) |
| Извлечение структурированных данных из UBL- или CII-XML |
| Справочник форматов, обязательных полей, кодов и сроков |
Интеграция с BuchPilot
E-Invoice MCP может быть интегрирован как плагин в MCP-сервер BuchPilot:
import { registerEInvoiceTools } from "einvoice-mcp";
registerEInvoiceTools(server);Комбинация: BuchPilot создает счет в Lexoffice -> извлечение данных -> создание XRechnung -> готовый электронный счет.
Поддерживаемые стандарты
Стандарт | Версия | Статус |
XRechnung | 3.0.2 | Создание + проверка |
EN 16931 | — | Основа для XRechnung |
UBL 2.1 | — | XML-синтаксис для XRechnung |
CII (Cross Industry Invoice) | — | Извлечение (чтение) |
ZUGFeRD / Factur-X | 2.3 | Извлечение (чтение), создание в планах |
FAQ / Устранение неполадок
«XML не удалось распарсить»
Является ли XML корректным (well-formed)? (Все ли теги правильно закрыты?)
Действительно ли это счет UBL или CII? (Корневой элемент должен быть
<Invoice>или<CrossIndustryInvoice>)Используется ли кодировка UTF-8?
Валидация показывает ошибку «BR-DE-13: Buyer Reference обязателен»
Ссылка на покупателя (BT-10) является обязательной в XRechnung. Для счетов государственным заказчикам это Leitweg-ID. Для B2B-счетов это может быть любая ссылка (например, номер заказа).
{
"buyerReference": "04011000-12345-67"
}Валидация показывает предупреждение «BR-DE-21: Рекомендуется номер телефона»
Это только предупреждение, а не ошибка. Счет все равно валиден. Однако для лучшей совместимости рекомендуется указать номер телефона продавца.
Какие существуют налоговые категории?
Код | Название | Описание | Налоговые ставки |
S | Стандарт | Обычная налоговая ставка | 19%, 7% |
Z | Нулевая ставка | 0% (например, внутрисоюзная с освобождением от НДС) | 0% |
E | Освобождено от налога | например, малый бизнес согласно § 19 UStG | 0% |
AE | Обратное начисление | Налоговое обязательство получателя (§ 13b UStG) | 0% |
K | Внутрисоюзная | Необлагаемая внутрисоюзная поставка | 0% |
Какие существуют коды единиц измерения?
Код | Название | Описание |
H87 | Штука | Отдельная единица (по умолчанию) |
HUR | Час | Рабочий час |
DAY | День | Рабочий день |
MON | Месяц | Календарный месяц |
KGM | Килограмм | Вес |
MTR | Метр | Длина |
LTR | Литр | Объем |
MTK | Квадратный метр | Площадь |
SET | Набор/Комплект | Комплектация |
C62 | Единица (общая) | Общая единица измерения |
Сервер запускается, но Claude не распознает инструменты
Проверьте, корректен ли файл
claude_desktop_config.jsonПерезапустите Claude Desktop после внесения изменений в конфигурацию
Проверьте логи:
~/Library/Logs/Claude/mcp.log(macOS)
Лицензия
MIT — свободно для использования, в том числе в коммерческих целях.
Автор
MaKri — GitHub
Available Tools
6 toolsconvert_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.
| Name | Required | Description | Default |
|---|---|---|---|
| direction | Yes | Konvertierungsrichtung | |
| input | Yes | Input-Daten: XML-String fuer ubl/cii, JSON-String fuer json | |
| validate_output | No | Output nach Konvertierung validieren (nur fuer XML-Output) |
TDQS
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.
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.
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.
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.
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.
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.
| Name | Required | Description | Default |
|---|---|---|---|
| invoiceNumber | Yes | Rechnungsnummer (eindeutig) | |
| issueDate | Yes | Rechnungsdatum (YYYY-MM-DD) | |
| dueDate | No | Faelligkeitsdatum (YYYY-MM-DD) | |
| paymentTerms | No | Zahlungsbedingungen (z.B. 'Zahlbar innerhalb von 30 Tagen') | |
| seller | Yes | Rechnungssteller | |
| buyer | Yes | Rechnungsempfaenger | |
| lineItems | Yes | Rechnungspositionen | |
| currency | No | Waehrung (ISO 4217) | EUR |
| paymentMeansCode | No | Zahlungsart: 30=Ueberweisung, 58=SEPA-Ueberweisung, 59=SEPA-Lastschrift | 58 |
| iban | No | IBAN fuer Zahlung | |
| bic | No | BIC | |
| bankName | No | Name der Bank | |
| buyerReference | No | Leitweg-ID oder Kaeufer-Referenz (BT-10, Pflicht in XRechnung) | |
| orderReference | No | Bestellnummer des Kaeufers (BT-13) | |
| note | No | Freitext-Bemerkung |
TDQS
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.
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.
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.
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.
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.
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.
| Name | Required | Description | Default |
|---|---|---|---|
| invoiceNumber | Yes | Rechnungsnummer (eindeutig) | |
| issueDate | Yes | Rechnungsdatum (YYYY-MM-DD) | |
| dueDate | No | Faelligkeitsdatum (YYYY-MM-DD) | |
| paymentTerms | No | Zahlungsbedingungen | |
| seller | Yes | Rechnungssteller | |
| buyer | Yes | Rechnungsempfaenger | |
| lineItems | Yes | Rechnungspositionen | |
| currency | No | Waehrung (ISO 4217) | EUR |
| iban | No | IBAN fuer Zahlung | |
| bic | No | BIC | |
| buyerReference | No | Leitweg-ID / Kaeufer-Referenz (BT-10) | |
| orderReference | No | Bestellnummer des Kaeufers (BT-13) | |
| note | No | Freitext-Bemerkung |
TDQS
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.
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.
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.
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.
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.
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.
| Name | Required | Description | Default |
|---|---|---|---|
| xml | No | E-Rechnung XML als String | |
| base64 | No | Base64-kodierte XML-Datei |
TDQS
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.
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.
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.
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.
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.
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.
| Name | Required | Description | Default |
|---|---|---|---|
| format | No | Welches Format abfragen | all |
| topic | No | overview=Formatbeschreibung, required_fields=Pflichtfelder, tax_categories=USt-Kategorien, unit_codes=Einheiten, deadlines=Fristen | overview |
TDQS
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.
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.
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.
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.
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.
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.
| Name | Required | Description | Default |
|---|---|---|---|
| xml | No | E-Rechnung XML als String | |
| base64 | No | Base64-kodierte XML-Datei | |
| level | No | Validierungstiefe: syntax=well-formed, schema=Struktur, full=inkl. BR-DE-Regeln | full |
TDQS
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.
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.
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.
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.
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.
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.
6 tool updates
v0.1.2- First observed
convert_format - First observed
create_xrechnung - First observed
create_zugferd - First observed
extract_data - First observed
get_format_info - First observed
validate_invoice
TDQS
Scored across 6 tools
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.
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.
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.
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
Related MCP Connectors
Create, validate, convert & extract compliant e-invoices (UBL, Factur-X, ZUGFeRD, XRechnung)
Validate, generate & convert EU e-invoices (UBL, CII, XRechnung, Factur-X) — EN 16931 pre-validated.
XRechnung and ZUGFeRD e-invoicing (EN 16931): create, validate, check Leitweg-IDs, German VAT.
Generate & validate EN 16931 e-invoices (Factur-X, ZUGFeRD, XRechnung); verification certificates
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