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 does disclose what the call returns (rule violations, billing profile, totals, extracted invoice JSON) and the accepted input dialects. It omits any mention of failure behavior, e.g. malformed XML handling or whether errors surface as violations versus exceptions, which is the remaining gap.

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 dense sentence front-loads the action and resource, then layers formats, ruleset and return payload. No filler or repetition.

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, no-annotation tool, the description covers input dialects, the standard applied, and the outputs returned, which is close to complete. Without an output schema, some structure of the returned violations/totals remains unstated, but the essentials an agent needs are present.

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 both 'xml' and 'operation' including the validate/parse meanings, which the description merely echoes. Baseline 3 is appropriate since the description adds no syntax or format detail beyond 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?

States specific verbs (validate/parse), the exact resource (Peppol BIS Billing 3.0 e-invoice), the accepted syntaxes (UBL 2.1 Invoice/CreditNote, UN/CEFACT CII) and the ruleset (CEN TC 434). This clearly distinguishes it from siblings like validate_facturx without opening the other schema.

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 two modes of use and the schema marks 'validate' as the default, but there is no explicit when-to-use versus when-not guidance or a named alternative among the many sibling validators. Usage is inferable but not spelled out.

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