check_vat_category_code

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

There are no annotations, so the description carries the full burden of behavioral disclosure. It clearly indicates a read-only membership check rather than a mutation or retrieval operation. It does not explain edge-case behavior such as case sensitivity or whether an invalid code returns false versus an error, but for a simple predicate with an output schema this is acceptable.

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, front-loaded sentence with no filler or redundant phrasing. It conveys the complete purpose in minimal words and earns each word's place.

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 one-parameter validation tool with an output schema, the description is mostly complete. It would be stronger if it pointed to list_vat_category_codes for obtaining valid code values, or explicitly distinguished this from the sibling check_vatex_code. As written, an agent can still invoke it correctly but without routing guidance.

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 only defines 'code' as a string, providing no semantic meaning. The description adds meaningful context by identifying it as a UNCL5305 VAT category code to be checked for recognition. It could be improved with an example or format hint, but with only one parameter this is largely sufficient.

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 uses a specific verb ('Check whether') and a specific resource ('UNCL5305 VAT category code'), making the tool's function immediately clear. It also differentiates itself from sibling tools like check_vatex_code by naming the exact code list standard.

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 usage context: use this tool when you need to verify whether a given code is a valid UNCL5305 VAT category code. However, it does not explicitly mention alternatives such as list_vat_category_codes for retrieving all valid codes, or provide any when-not-to-use guidance.

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