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

Beyond the readOnly/non-destructive/idempotent annotations, the description discloses that documents are validated in memory and never stored or logged, and it provides a detailed response shape with verdict, findings, counts, confidence, sources, and disclaimer. The only concern is the internal tension between 'without validating' and the described validation verdict/findings.

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 first sentence front-loads the extracted fields well, but it is a dense run-on list, and the response details are lengthy despite the presence of an output schema. The information is useful but not optimally structured for quick agent parsing.

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 output schema and annotations, the description is largely complete: it covers purpose, behavior, privacy/storage, cost, and response contents. The main gap is the unexplained required xml input parameter, which leaves the calling contract underspecified.

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 has one required parameter named 'xml' with an empty description and 0% schema description coverage. The tool title implies a UBL invoice input, but the description never explains the xml parameter's expected format, encoding, size, or whether it is raw XML versus base64.

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 states a specific verb and resource: reading key fields of a UBL invoice, including seller/buyer data, dates, totals, VAT, payment means, and attachments. It also distinguishes the tool from validation by saying 'without validating', though the later mention of verdict/findings and in-memory validation creates some ambiguity.

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 phrase 'without validating. Free.' implies this is the non-validating, no-cost extraction option, which helps distinguish it from validate_invoice. However, it does not explicitly say when to use this tool versus check_trn, readiness_report, or validate_invoice, nor does it state any exclusions.

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