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

Goes beyond the annotations by disclosing two behaviors an agent cannot infer from structured fields: the call may consume credits, and 'nothing is sent to anyone' (data-handling/privacy). It also enumerates the response contents (detected type, valid yes/no, summary, broken rules with XPath) even though no output schema exists.

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?

Front-loaded with the action and standards, followed by compact sentences on returns, privacy, cost, and endpoint. Slightly dense in the first clause (long parenthetical and acronym list), but nothing is wasted.

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?

With no output schema, the description helpfully covers return values, cost, and privacy, which is most of what a caller needs. It does not state that at least one of xml or data_base64 must be supplied, nor any size/error constraints, which is a real gap given zero required parameters.

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 each of the three parameters is already documented in the schema. The description adds only the accepted input forms (XML or hybrid PDF) without clarifying mutual exclusivity of xml vs data_base64 or the auto-detection behavior of einvoice_type.

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?

States a specific verb (validate) plus resource (e-invoice) and scopes it to named standards (EN 16931, XRechnung, Peppol BIS) over XML or hybrid PDF. This clearly separates it from siblings like dochorizon_convert_einvoice and dochorizon_capture_einvoice.

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 the use case (checking an invoice against its standard) but never states when to choose this over convert_einvoice or when validation is not appropriate. The alternative for overriding detection, dochorizon_list_einvoice_types, is referenced only in the schema, not the description.

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