VAT report

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

The readOnlyHint annotation already indicates this is a safe read operation. The description adds only 'Defaults to JSON,' which is also present in the format parameter's schema description. It does not disclose what the report contains, how periods are filtered, or any other behavioral traits beyond the annotations.

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 sentence with no redundant words. It front-loads the core purpose immediately. While minimal, it is appropriately sized for the information it conveys, consistent with high-scoring concise examples.

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 compensate by explaining what the VAT report returns or how to interpret the output. It does not, and it also lacks guidance on parameter combinations or limitations. Given the tool's moderate complexity (6 optional parameters), this is under-specified.

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?

All six parameters have descriptions in the schema, achieving 100% coverage. The description itself does not add any parameter semantics beyond stating the default JSON format, which is already documented. Thus the baseline of 3 applies.

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 the specific verb 'Return' and identifies the resource as 'the VAT report for a document.' It is clear but does not explicitly differentiate from sibling VAT tools such as banana_vat_balance or banana_vat_projection, so it earns a 4 rather than a 5.

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 provides no guidance on when to use this tool versus alternatives. It simply states what it does without context, exclusions, or preferred scenarios. This is a significant gap given the many related VAT tools in the sibling list.

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