Embed XRechnung XML into a PDF

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

No annotations are supplied, so the description carries the full behavioral burden, yet it discloses only the transformation itself. It says nothing about the response shape (base64 string vs. file/URL) despite there being no output schema, nor whether the XML is validated before embedding, nor whether the operation is synchronous. The output-schema gap is the most consequential omission.

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?

A single front-loaded sentence that states the operation, its inputs, and its output with no filler or redundancy.

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 two-parameter, fully documented transformation the core is covered, but with no annotations and no output schema the description should at least say what comes back (e.g. a base64 ZUGFeRD PDF). That single missing detail leaves the call contract slightly incomplete.

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% and both parameters are documented in the schema (invoicePdf64 = base64 PDF, xrechnungXml = XML to embed), so baseline 3 applies. The description adds only the qualifier 'existing' and the visual/PDF framing, adding little beyond the structured fields.

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 gives a precise verb (embed), both inputs (an existing XRechnung XML and a visual PDF), and the resulting artifact (a ZUGFeRD PDF). This implicitly separates it from create_zugferd_from_pdf, which starts from a PDF rather than an already-prepared XML, though no sibling is named explicitly.

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?

Usage is only implied by the word 'existing' — an agent can infer this tool is for when an XRechnung XML already exists. There is no explicit when-to-use/when-not statement and no pointer to the alternatives (create_xrechnung, create_zugferd_from_pdf, validate_xrechnung_xml) that a routing agent would need.

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