FacturX (Factur-X / ZUGFeRD e-invoicing)

facturx_dry_run

Read-onlyIdempotent

Check a complete ERP invoice JSON for Factur-X readiness without creating a file or using quota; returns readiness detail, request ID, and idempotency key.

Instructions

Check a complete ERP invoice JSON WITHOUT producing a file and WITHOUT using quota. Use it first, every time. Returns ready (true only when generationReadiness.status is 'ready'; success=false can still be ready), the readiness detail, request_id and idempotency_key.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "invoice": "<invoice>"
    },
    "name": "facturx_dry_run"
  }
}

Input Schema

Name	Required	Default
`output`	No	facturx_pdfa3
`invoice`	Yes
`validation_target`	No	en16931

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.2Nov 11, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds genuinely non-obvious behavior: quota is not consumed, and the crucial nuance that 'success=false can still be ready' depending on generationReadiness.status, plus the returned keys. That is real context an agent could not infer from annotations.

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?

Three short sentences, front-loaded with the mode-of-operation claim, then the usage directive, then the return semantics. No filler and every clause carries information.

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

Completeness4/5

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

An output schema exists, so return values needn't be spelled out, and the description still adds the one return nuance that matters. The notable gap is the opaque nested 'invoice' payload and the two unlabeled configuration parameters, which is the main risk for correct invocation on a read-only, non-destructive tool.

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

Parameters2/5

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

Schema description coverage is 0% across 3 parameters, and the 'invoice' parameter is a free-form nested object with additionalProperties=true, so its shape is entirely undocumented. The description only says the invoice must be 'complete' and never explains what 'output' or 'validation_target' control, so it fails to compensate for the coverage gap.

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?

States a specific verb and resource ('Check a complete ERP invoice JSON') and immediately scopes it with two behavioral differentiators: no file is produced and no quota is consumed. That is enough to tell it apart from facturx_convert (which emits a file) without opening either schema.

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 directive 'Use it first, every time' gives clear, actionable ordering guidance for when to reach for this tool. It stops short of naming an alternative or a when-not condition, but the 'without producing a file' framing implicitly covers the conversion case.

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

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