Get reseller by VAT ID

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

No annotations are provided, so the description carries the full behavioral burden, and it discloses nothing: not what happens when the VAT ID is unknown (error vs. empty), whether the lookup is exact-match or normalized, nor what fields a reseller record contains.

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?

It is short, but this is under-specification rather than conciseness — a four-word restatement of the name that earns no informational value and is not front-loaded with any useful context.

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 single-parameter lookup with no annotations or output schema, the description should at least describe the not-found behavior and the shape of the returned reseller. None of that is present, leaving the agent unable to predict the response.

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 the single parameter already documents "VAT / UID number" with a minLength constraint, so the schema does the work. The description adds nothing on format (country prefix, digits only) but the baseline of 3 applies when coverage is complete.

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 is essentially the tool name reworded: "GetResellerByVatId" for get_reseller_by_vat_id. It conveys no resource detail beyond the identifier and does not distinguish this tool from the closely related siblings get_reseller or get_company_by_vat_id.

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?

There is no guidance on when to use this lookup versus get_reseller (which presumably fetches by other identifiers) or get_company_by_vat_id. The agent is left to infer the selection rule entirely from the name.

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