Check Vat Category Code

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

No annotations are provided, so the description carries the behavioral burden. The verb 'check' signals a read-only, non-mutating lookup, and the reference to UNCL5305 defines the recognition standard. Returning the result is covered by the output schema, so no further behavioral detail is essential.

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 description is a single focused sentence with no filler. The key predicate and standard are stated upfront, making it easy for an agent to parse quickly.

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?

This is a low-complexity tool with one required string parameter and an output schema present. The description, combined with the schema, provides everything an agent needs to select and invoke the tool correctly.

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 input schema gives only a bare 'string' type with 0% description coverage, but the description fully explains that 'code' is the candidate UNCL5305 VAT category code to validate. This fully compensates for the schema's lack of parameter documentation.

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 ('check') and resource ('UNCL5305 VAT category code'), making the tool's purpose immediately clear. It is easily distinguished from the sibling list_vat_category_codes, which lists codes rather than validating a single one.

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 clearly implies the intended use case: validating whether a single code is a recognized VAT category code. It does not explicitly name alternatives or exclusions, but for a simple predicate tool the context is sufficiently clear.

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