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

Adds context beyond the annotations: one metered call (cost awareness) and an account/OAuth requirement. The readOnlyHint/idempotentHint annotations are consistent with a pure transformation. It omits what the result looks like on validation failure, but the safety and cost profile is well covered.

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?

Two dense sentences, front-loaded with the conversion capability and followed by cost/account constraints. No filler and nothing repeated from the schema.

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 should say what the tool returns, yet 'validate the result' only hints at a validation outcome and never says whether the converted XML is returned inline, as a link, or alongside a report. Everything else an agent needs to call it is 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 coverage is 100%, so the baseline is 3, but the description earns more by naming the accepted source dialects, which the 'xml' schema entry does not ('The source invoice XML'). The target format names are already enumerated in the schema, so the description adds only marginal detail there.

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 (convert) with the exact source dialects (UBL, CII/Factur-X) and the four target formats, plus the extra validation step. This is clearly distinguishable from parse_invoice, validate_invoice, and generate_invoice without opening any 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?

Establishes the usage context (you already have an invoice XML and need a different profile) and states the prerequisite of an InvoiceVerify account with OAuth sign-in. It stops short of explicit exclusions, e.g. telling the agent to use validate_invoice when no conversion is wanted.

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